Some standard content:
Military Standard of the Electronic Industry of the People's Republic of China FL5860
SJ20762—1999
Measurementmethods for
parameters of gas laser lasers
1999-11-10 Issued
1999-12-01 Implementation
Approved by the Ministry of Information Industry of the People's Republic of China 1 Scope
2 Referenced documents
3 Definitions
4 General requirements
5 Detailed requirements
Method 101
Method 102
Method 103
Method 104
Method 105
Method 106
Method 107
Method 108
Method 109
Method 110
Method 111
Method 112
Method 113
Test of ignition voltage
Test of optimum operating current
Test of working voltage [tube voltage drop]
Test of output power
Test of output power (suitable for high power)Test of output power instability
Test of light direction deviationFour-quadrant detector methodTest of light beam direction deviationPhotographic method
Test of transverse modePinhole scanning method
Test of transverse modeSwept frequency interferometer method (arbitration method)Test of transverse modePhotographic method (suitable for high power)Single-mode light Beam diameter and divergence angle test Pinhole scanning method. Beam attenuation and divergence angle test Circular hole method Method 114
Beam diameter and divergence angle test Long focal length circular hole method Method 115
Method 116
Method 201
Method 202
Method 203
Beam diameter and divergence angle test Double circular hole method Polarization degree test
Optimum working voltage test
Pulse width test
Pulse repetition frequency test
Pulse energy test
Method 204
Method 205||t t||Method 206
Test of output pulse energy instability
Test of pulse peak power
Test of average value of repeated pulse peak power·…Method 207
Method 301
Method 302
Test of laser wavelength
Test of laser efficiency
Method 303
Test of laser warm-up time
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1 Scope
Military standard of electronics industry of the People's Republic of China Test methods for gas laser parameters
Measurement methods for parameters of gas Iasers1.1 Subject content
This standard specifies the test methods for optoelectronic parameters of gas lasers. 1.2 Scope of application
SJ 20762-1999
This standard is applicable to the test of the optoelectronic parameters of various types of gas lasers. The test of the optical parameters of other types of lasers can also be used as a reference.
1.3 Application Guide
1.3.1 This standard provides a systematic test method for the optoelectronic parameters of various types of gas lasers (hereinafter referred to as lasers) to determine the actual working ability of the laser under certain conditions. Sometimes more than two test methods are proposed for one parameter in the standard, which can be selected according to the specific situation. 1.3.2 This standard is the basis for the test of the optoelectronic parameters of lasers specified in the general specification or product detailed specification (hereinafter referred to as detailed specification) or other technical documents. 2 Referenced documents
GB7247--1995 Radiation safety, equipment classification, requirements and user guide for laser products 3 Definitions
3.1 Laserlaser
A generator of electromagnetic radiation in the optical range based on controlled stimulated emission. 3.2 Gas laser
Laser whose working substance is gaseous.
3.3 Continuous wave laser [Cw laser] Laser whose laser output is continuous rather than pulsed. A laser with a continuous output period of less than 0.25 s is called a continuous wave laser.
3.4 Pulsed laser
Laser that releases energy in the form of a single pulse or a pulse train, and the pulse duration is less than 0.25 s. A pulse train is approximately equivalent to a single pulse.
3.5 Repetitively pulsed laser A laser that can produce a series of multiple pulses of radiated energy with equal time intervals. 3.6 Operating currents The Ministry of Information Industry of the People's Republic of China issued on November 10, 1999 and implemented on December 1, 1999
SJ20762—1999
When the laser is working, the operating current of the laser power supply. 3.7 Laser power supply laserpowersupply A specially made power supply used to excite the laser working material. Power supplies such as mains power supplies or batteries cannot be considered as laser power supplies.
3.81 Operating conditions The operating conditions of the laser refer to the operating mode, operating wavelength and required cooling conditions of the laser. 3.9 Transverse mode transverse mode
The intrinsic distribution state of the beam energy (power) density on the cross section perpendicular to the propagation direction of the electromagnetic wave in the optical resonator of the laser. If the distribution state is a Gaussian function of the distance from the beam axis, it is called the fundamental transverse mode (the lowest order transverse mode), commonly known as single mode, and represented by TEMo; in addition, they are all called high-order transverse modes, commonly known as multi-modes. 3.10 Beam (Gaussian beam) diameter beam (Gaussion beam) diametera, on any cross section of the beam, the diameter of the circle formed by all points where the power or energy density drops to 1/e of the central peak.
b, on any cross section of a Gaussian beam, the diameter of the circle containing 86% of the total beam energy (or power). 3. 11 Beam waist beam waist
The minimum diameter on the cross section of the laser beam. The beam waist diameter is determined by the distance between the two mirrors of the resonant cavity and its radius of curvature and the laser wavelength: the beam waist position is determined by the radius of curvature P, P, of the two mirrors of the resonant cavity, and the cavity length 1. For example: the waist position of the plane concave cavity is at the plane mirror: the waist position of the double concave cavity, when p=P, at the midpoint of the cavity length (1), when p±p, then the distance from the waist position to the concave mirror 1 is:
P+p-21
Where: Pi, P2, 1 are all in mra. 3.12 Efficiency The efficiency of a laser is the photoelectric conversion efficiency, that is, the ratio of the laser power (or laser energy) output by the laser to the electrical power (or energy) input by the laser power supply. 3.13 Laser warm-up time The time interval required for the laser to reach the parameter index specified in the detailed specification at a given working current from the moment of ignition is called the laser warm-up time. 4 General requirements 4.1 Test conditions 4.1.1 Test environment 4.1.1.1 Unless otherwise specified, the test shall be carried out under the following normal atmospheric conditions. a, temperature: 15~35℃; b, relative humidity: 45%~75%; c, air pressure: 86~106 kPa. 4.1.1.2 The entire test system shall be in an environment without obvious vibration, airflow, smoke and stray radiation, and shall not be subject to interference that affects the test results.
4.1.2 Test instruments and equipment
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SJ20762—1999
Test instruments and equipment should be stable and reliable and should work according to their specifications. 4. 1.2. 1
4.1.2.2 The laser power meter and energy meter used in the test should be above level 5, and other pointer instruments should not be lower than level 1.5. 4.1.2.3 The instruments and meters used in the test should be calibrated regularly by the metrology department and used within the validity period. 4.1.2.4 In order to protect the instrument from unauthorized sudden overload, it is allowed to use protective devices on the test equipment, but it should not affect the test accuracy.
4.1.3 Safety protection
Safety protection when testing laser parameters should comply with the relevant provisions in the User Guide, Chapter 3 of GB7247. 4.2 Laser under test
Unless otherwise specified, the laser under test shall be operated under the working procedures and working conditions specified in the detailed group specifications and this standard, and the relevant parameters shall be measured after stable operation. 5 Detailed requirements
5.1 See Section 4.1 for laser parameter test conditions. 5.2 The laser under test shall comply with the requirements of Section 4.2. 5.3 Lasers—General parameters Test methods are numbered in the 100 series. 5.4 The laser pulse parameter test method is numbered in the 200 series. 5.5 The test methods for other laser parameters are numbered in the 300 series. 3
1 Purpose
SJ 20762—1999
Method 101 Test of ignition voltage When the discharge tube of the laser ignites, measure the voltage applied between the two electrodes. 2 Test system diagram
The test system diagram is shown in Figure 101.
1-Laser power supply with continuously adjustable voltage: 2-DC ammeter: 3-High voltage voltmeter: 4-Laser discharge tube Figure 101
Note: It is allowed to add a ballast resistor at the anode end of the discharge tube during measurement. 3 Test procedure
3.1 Turn on the power supply and slowly increase the voltage between the two electrodes of the discharge tube from 0V until the discharge tube ignites. The voltage value at the moment of ignition is read from the voltmeter, which is the ignition voltage. 3.2 Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Differences in the initial state of the gas in the laser tube before ignition. 4.2 Adjust the speed of the power supply voltage.
4.3 Accuracy and reading error of voltmeter.
niKAoNrkAca
1 Purpose
SJ20762-—1999
Method 102 Test of optimal operating current
Measure the current value of the laser when it outputs maximum rate. 2 Test system diagram
The test system diagram is shown in Figure 102.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter; 3—Laser power meter; 4—Laser Figure 102
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 Adjust the working current to maximize the output power of the laser. At this time, the current value read from the ammeter is the optimal working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Accuracy of ammeter and reading error.
4.2 Instability of laser output power.
4.3 Errors caused by slow response speed of laser power meter -s-
SJ20762--1999
Method 103 Test of working voltage [tube voltage drop] Under a given working current, the laser measures the potential difference between the two electrodes of the discharge tube 2 Test system diagram
Test system diagram Figure 103.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter: 3—High voltage voltmeter: 4—Laser: 5—Laser power meter Figure 103
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 At a given operating current, read the voltage value from the voltmeter. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Measurement error of working current.
4.2 Accuracy and reading error of voltmeter.
niKAoNrkAca
1 Purpose
SJ 20762—1999
Method 104 Output power test
Under specified working conditions, measure the laser power output at the output end of the laser at a given working current. 2 Test block diagram
The test block diagram is shown in Figure 104.
1 - Laser power supply; 2 - Laser; 3 - Laser power meter Figure 104
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 The distance between the receiver of the laser power meter and the laser output end shall not be less than 10cm: and it should be ensured that the entire laser beam enters the receiver.
3.3 Confirm that the laser is working in the specified mode, adjust the current to the given working current, and use a power meter to measure the output power of the laser. Measure once every certain period of time (greater than the detector zero return time), measure 5 times in total, and take the average value. 4 Main sources of error
4.1 Accuracy of the power meter and errors in its readings. 4.2 Effects of non-laser radiation.
1
SJ 20762-1999
Method 105 Output power test (suitable for high power) Under specified working conditions, measure the laser power output at the output end of the laser at a given working current. 2 Test block diagram
The test block diagram is shown in Figure 105.
1—Laser regulated current power supply, 2—Laser: 3—Optical shutter: 4—Attenuator (when necessary): 5—Narrowband filter (when necessary): 6 Laser power meter Figure 105
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 Aim the laser power meter probe at the output beam of the laser and allow it to be fully received. 3.3 Turn on the power of the laser power meter, select the appropriate range, and calibrate its signature point. 3.4 Read the power meter reading once at a certain interval (such as 3 minutes) (before each measurement, make sure the instrument returns to the initial state), and measure n (n>10) times in total. The output power is calculated according to the following formula: Pa
fsfz hsi
Where: Pout output power, W;
,- attenuator transmittance, %;
z narrowband filter transmittance, %;
n measurement number
Pauti the output power value measured for the ith time, W. 4 Main sources of error
4.1 Improper use of laser power meter.
4.2 Instrument reading error.
4.3 Errors caused by attenuators and narrow-band filters, 5 Special requirements
Should be specified in the detailed specifications:
a Accuracy of laser power meter:wwW.bzxz.Net
b. Allowable error of attenuators and narrowband filters; c. other.
HKAONrKAca
(105—1)
1Purpose
SJ 20762—1999
Method 106 Test of output power instability Within a specified time range, the characteristics of the spot laser output power fluctuation over time (less than 1Hz) are measured. 2 Test block diagram
The test block diagram is shown in Figure 106.
1-Laser regulated current power supply: 2-Laser: 3-Attenuator: 4-Photodetector: 5-Impedance transformation linear amplifier; 6-Recording instrument Figure 106
3 Test procedure
3.1 Preheat the laser as specified in the detailed specifications. 3.2 Aim the photodetector at the laser beam and turn on the recording instrument. Adjust the recording instrument to the appropriate sensitivity and sampling rate.
3.3 Turn on the entire test system and take samples [record] within the specified time range (not less than 1 hour). Take n (n≥5) values at equal time intervals on the sampling [record 1 curve and calculate the average value. pa
Where: P - the i-th reading on the recording curve, W. 3.4 On the sampling [record 1 curve, find the maximum value P. and the minimum value P.AP = Prmax - Pmin
3.5 Use any of the following formulas to calculate the instability of the light shielding device's output power within the specified time range: s
Z(RP)
Wherein, S, — standard deviation of output power instability, %: P, P—see formula (106--1).
Where: S, —output power instability, %p-
—see formula (106-1).
4p — See formula (106—2).
Note, when indicating that the output power is unstable, the time range must be given, (106--1)
(106—2)
(106—3)
(106—-4)
4Main sources of error
SJ 20762—1999
4.1 Slow response speed of photodetector, temperature drift, etc. 4.2 The optical attenuator is unstable.
4.3 Sampling of recording instruments [Recording error. 4.4 The mechanical device of the test system is improperly set up. 4.5 Influences of ambient temperature fluctuations, airflow and stray light. 5 Special requirements
5.1 The photodetector must have high sensitivity and sufficiently fast time response to the light of the received wavelength and be used under the specified power density without saturation. 5.2 The test system must be linear within the measured power range. 5.3 Ensure sufficient accuracy of the recording instrument.
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iKAoNrKAca-3 Ensure sufficient accuracy of the recording instrument.
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iKAoNrKAca-3 Ensure sufficient accuracy of the recording instrument.
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iKAoNrKAca-1 The test conditions of laser parameters are shown in 4.1. 5.2 The laser under test shall comply with the provisions of 4.2. 5.3 Laser - General parameter test methods are numbered as 100 series. 5.4 Laser pulse parameter test methods are numbered as 200 series. 5.5 Laser other parameter test methods are numbered as 300 series. 3
1 Purpose
SJ 20762—1999
Method 101 Test of ignition voltage When the laser discharge tube ignites, measure the voltage applied between the two electrodes. 2 Test system diagram
The test system diagram is shown in Figure 101.
1-Laser power supply with continuously adjustable voltage: 2-DC ammeter: 3-High voltage voltmeter: 4-Laser discharge tube Figure 101
Note: It is allowed to add a ballast resistor at the anode end of the discharge tube during measurement. 3 Test procedure
3.1 Turn on the power supply, and slowly increase the voltage between the two electrodes of the discharge tube from 0V until the discharge tube ignites. Read the voltage value at the moment of ignition from the voltmeter, which is the ignition voltage. 3.2 Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Differences in the initial state of the gas in the laser tube before ignition. 4.2 Adjust the speed of the power supply voltage.
4.3 Accuracy of the voltmeter and reading error.
niKAoNrkAca
1 Purpose
SJ20762-—1999
Method 102 Test of the optimal working current
Measure the current value of the laser at the maximum output rate. 2 Test system diagram
See Figure 102 for the test system diagram.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter; 3—Laser power meter; 4—Laser Figure 102
3 Test procedure
3.1 Preheat the laser according to the detailed specifications. 3.2 Adjust the working current to maximize the output power of the laser. The current value read from the ammeter at this time is the optimal working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Accuracy of the ammeter and reading error.
4.2 Instability of the laser output power.
4.3 Error caused by the slow response speed of the laser power meter-s-
SJ20762--1999
Method 103 Test of working voltage [tube voltage drop] The potential difference between the two electrodes of the discharge tube is measured at a given working current of the laser. 2 Test system diagram
Test system diagram Figure 103.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter: 3—High voltage voltmeter: 4—Laser: 5—Laser power meter Figure 103
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 Read the voltage value from the voltmeter at a given working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Measurement error of working current.
4.2 Accuracy of voltmeter and reading error.
niKAoNrkAca
1 Purpose
SJ 20762—1999
Method 104 Output power test
Measure the laser power output at the output end of the laser at a given working current under specified working conditions. 2 Test block diagram
See Figure 104 for the test block diagram.
1-Laser power supply; 2-Laser; 3-Laser power meter Figure 104
3 Test procedure
3.1 Preheat the laser according to the detailed specification. 3.2 The distance between the receiver of the laser power meter and the laser output terminal shall not be less than 10cm: and it should be ensured that the laser beam is completely emitted into the receiver.
3.3 Confirm that the laser is working in the specified mode, adjust the current to the given working current, and measure the output power of the laser with a power meter. Measure it once every certain time (greater than the detector zero return time), measure it 5 times in total, and take the average value. 4 Main sources of error
4.1 Accuracy of the power meter and its reading error. 4.2 Influence of non-laser radiation.
1 Self
SJ 20762-1999
Method 105 Output power test (suitable for high power) Under the specified working conditions, measure the laser power output at the output end of the laser at a given working current. 2 Test block diagram
The test block diagram is shown in Figure 105.
1—Laser regulated current power supply, 2—Laser: 3—Optical shutter: 4—Attenuator (when necessary): 5—Narrowband filter (when necessary): 6 Laser power meter Figure 105
3 Test procedure
3.1 Preheat the laser according to the detailed specifications. 3.2 Aim the laser power meter probe at the output beam of the laser and make it receive all of it. 3.3 Turn on the laser power meter power supply, select the appropriate range, and calibrate its signature point. 3.4 Read the power meter reading once at a certain interval (such as 3 minutes) (before each measurement, it must be confirmed that the instrument has returned to the initial state), and measure n (n>10) times in total. The output power is calculated as follows: Pa
fsfz h
Where: Pout output power, W;
,- attenuator transmittance, %;
z narrowband filter transmittance, %;
n number of measurements
Pauti output power value measured for the ith time, W. 4 Main sources of error
4.1 Improper use of laser power meter.
4.2 Instrument reading error.
4.3 Error caused by attenuator and narrowband filter, 5 Special requirements
Should be specified in the detailed specifications:
a Accuracy of laser power meter:
b. Allowable error of attenuator and narrowband filter; c. Others.
HKAONrKAca
(105—1)
1 Purpose
SJ 20762—1999
Method 106 Test of output power instability The characteristics of the spot laser output power fluctuation over time (less than 1Hz) within the specified time range. 2 Test block diagram
The test block diagram is shown in Figure 106.
1-Laser current stabilizer: 2-Laser: 3-Attenuator: 4-Photodetector: 5-Impedance conversion linear amplifier; 6-Recording instrument Figure 106
3 Test procedure
3.1 Preheat the laser according to the provisions of the detailed specification. 3.2 Aim the photodetector at the laser beam and turn on the recording instrument. Adjust the recording instrument to the appropriate sensitivity and sampling [recording speed.
3.3 Turn on the entire test system and sample [record] within the specified time range (not less than 1h). Take n (n≥5) values at equal time intervals on the sampling [record 1 curve and calculate the average value. pa
Where: P - the i-th reading on the recording curve, W. 3.4 On the sampling [record 1 curve, find the maximum value P. and the minimum value P.AP = Prmax - Pmin
3.5 Use any of the following formulas to calculate the instability of the output power of the light shield within the specified time range: s
Z(RP)
Where: S, — standard deviation of output power instability, %: P, P—see formula (106--1).
Where: S, — output power instability, %p-
—see formula (106--1).
4p — See formula (106—2).
Note, when indicating that the output power is unstable, the time range must be given, (106--1)
(106—2)
(106—3)
(106—-4)
4Main sources of error
SJ 20762—1999
4.1 Slow response speed of the photodetector, temperature drift, etc. 4.2 Unstable optical attenuator.
4.3 Sampling [recording error of the recording instrument. 4.4 Improper placement of the mechanical device of the test system. 4.5 Influences of ambient temperature fluctuations, airflow and stray light, etc. 5Special requirements
5.1 The photodetector must have high sensitivity and sufficiently fast time response to the light of the received wavelength, and be used under the specified power density without saturation. 5.2 The test system must be linear within the power range. 5.3 Ensure that the recording instrument has sufficient accuracy.1 The test conditions of laser parameters are shown in 4.1. 5.2 The laser under test shall comply with the provisions of 4.2. 5.3 Laser - General parameter test methods are numbered as 100 series. 5.4 Laser pulse parameter test methods are numbered as 200 series. 5.5 Laser other parameter test methods are numbered as 300 series. 3
1 Purpose
SJ 20762—1999
Method 101 Test of ignition voltage When the laser discharge tube ignites, measure the voltage applied between the two electrodes. 2 Test system diagram
The test system diagram is shown in Figure 101.
1-Laser power supply with continuously adjustable voltage: 2-DC ammeter: 3-High voltage voltmeter: 4-Laser discharge tube Figure 101
Note: It is allowed to add a ballast resistor at the anode end of the discharge tube during measurement. 3 Test procedure
3.1 Turn on the power supply, and slowly increase the voltage between the two electrodes of the discharge tube from 0V until the discharge tube ignites. Read the voltage value at the moment of ignition from the voltmeter, which is the ignition voltage. 3.2 Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Differences in the initial state of the gas in the laser tube before ignition. 4.2 Adjust the speed of the power supply voltage.
4.3 Accuracy of the voltmeter and reading error.
niKAoNrkAca
1 Purpose
SJ20762-—1999
Method 102 Test of the optimal working current
Measure the current value of the laser at the maximum output rate. 2 Test system diagram
See Figure 102 for the test system diagram.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter; 3—Laser power meter; 4—Laser Figure 102
3 Test procedure
3.1 Preheat the laser according to the detailed specifications. 3.2 Adjust the working current to maximize the output power of the laser. The current value read from the ammeter at this time is the optimal working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Accuracy of the ammeter and reading error.
4.2 Instability of the laser output power.
4.3 Error caused by the slow response speed of the laser power meter-s-
SJ20762--1999
Method 103 Test of working voltage [tube voltage drop] The potential difference between the two electrodes of the discharge tube is measured at a given working current of the laser. 2 Test system diagram
Test system diagram Figure 103.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter: 3—High voltage voltmeter: 4—Laser: 5—Laser power meter Figure 103
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 Read the voltage value from the voltmeter at a given working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Measurement error of working current.
4.2 Accuracy of voltmeter and reading error.
niKAoNrkAca
1 Purpose
SJ 20762—1999
Method 104 Output power test
Measure the laser power output at the output end of the laser at a given working current under specified working conditions. 2 Test block diagram
See Figure 104 for the test block diagram.
1-Laser power supply; 2-Laser; 3-Laser power meter Figure 104
3 Test procedure
3.1 Preheat the laser according to the detailed specification. 3.2 The distance between the receiver of the laser power meter and the laser output terminal shall not be less than 10cm: and it should be ensured that the laser beam is completely emitted into the receiver.
3.3 Confirm that the laser is working in the specified mode, adjust the current to the given working current, and measure the output power of the laser with a power meter. Measure it once every certain time (greater than the detector zero return time), measure it 5 times in total, and take the average value. 4 Main sources of error
4.1 Accuracy of the power meter and its reading error. 4.2 Influence of non-laser radiation.
1 Self
SJ 20762-1999
Method 105 Output power test (suitable for high power) Under the specified working conditions, measure the laser power output at the output end of the laser at a given working current. 2 Test block diagram
The test block diagram is shown in Figure 105.
1—Laser regulated current power supply, 2—Laser: 3—Optical shutter: 4—Attenuator (when necessary): 5—Narrowband filter (when necessary): 6 Laser power meter Figure 105
3 Test procedure
3.1 Preheat the laser according to the detailed specifications. 3.2 Aim the laser power meter probe at the output beam of the laser and make it receive all of it. 3.3 Turn on the laser power meter power supply, select the appropriate range, and calibrate its signature point. 3.4 Read the power meter reading once at a certain interval (such as 3 minutes) (before each measurement, it must be confirmed that the instrument has returned to the initial state), and measure n (n>10) times in total. The output power is calculated as follows: Pa
fsfz h
Where: Pout output power, W;
,- attenuator transmittance, %;
z narrowband filter transmittance, %;
n number of measurements
Pauti output power value measured for the ith time, W. 4 Main sources of error
4.1 Improper use of laser power meter.
4.2 Instrument reading error.
4.3 Error caused by attenuator and narrowband filter, 5 Special requirements
Should be specified in the detailed specifications:
a Accuracy of laser power meter:
b. Allowable error of attenuator and narrowband filter; c. Others.
HKAONrKAca
(105—1)
1 Purpose
SJ 20762—1999
Method 106 Test of output power instability The characteristics of the spot laser output power fluctuation over time (less than 1Hz) within the specified time range. 2 Test block diagram
The test block diagram is shown in Figure 106.
1-Laser current stabilizer: 2-Laser: 3-Attenuator: 4-Photodetector: 5-Impedance conversion linear amplifier; 6-Recording instrument Figure 106
3 Test procedure
3.1 Preheat the laser according to the provisions of the detailed specification. 3.2 Aim the photodetector at the laser beam and turn on the recording instrument. Adjust the recording instrument to the appropriate sensitivity and sampling [recording speed.
3.3 Turn on the entire test system and sample [record] within the specified time range (not less than 1h). Take n (n≥5) values at equal time intervals on the sampling [record 1 curve and calculate the average value. pa
Where: P - the i-th reading on the recording curve, W. 3.4 On the sampling [record 1 curve, find the maximum value P. and the minimum value P.AP = Prmax - Pmin
3.5 Use any of the following formulas to calculate the instability of the output power of the light shield within the specified time range: s
Z(RP)
Where: S, — standard deviation of output power instability, %: P, P—see formula (106--1).
Where: S, — output power instability, %p-
—see formula (106--1).
4p — See formula (106—2).
Note, when indicating that the output power is unstable, the time range must be given, (106--1)
(106—2)
(106—3)
(106—-4)
4Main sources of error
SJ 20762—1999
4.1 Slow response speed of the photodetector, temperature drift, etc. 4.2 Unstable optical attenuator.
4.3 Sampling [recording error of the recording instrument. 4.4 Improper placement of the mechanical device of the test system. 4.5 Influences of ambient temperature fluctuations, airflow and stray light, etc. 5Special requirements
5.1 The photodetector must have high sensitivity and sufficiently fast time response to the light of the received wavelength, and be used under the specified power density without saturation. 5.2 The test system must be linear within the power range. 5.3 Ensure that the recording instrument has sufficient accuracy.5 The test methods for other laser parameters are numbered as 300 series. 3
1 Purpose
SJ 20762—1999
Method 101 Test of ignition voltage When the discharge tube of the laser ignites, measure the voltage between the two electrodes. 2 Test system diagram
The test system diagram is shown in Figure 101.
1-Laser power supply with continuously adjustable voltage: 2-DC ammeter: 3-High voltage voltmeter: 4-Laser discharge tube Figure 101
Note: It is allowed to add a ballast resistor at the anode end of the discharge tube during measurement. 3 Test procedure
3.1 Turn on the power supply, and increase the voltage between the two electrodes of the discharge tube slowly from 0V until the discharge tube ignites. Read the voltage value at the moment of ignition from the voltmeter, which is the ignition voltage. 3.2 Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Differences in the initial state of the gas in the laser tube before ignition. 4.2 How fast or slow the power supply voltage is adjusted.
4.3 Accuracy of the voltmeter and the reading error.
niKAoNrkAca
1 Purpose
SJ20762--1999
Method 102 Test of the optimal operating current
Measure the current value of the laser at the maximum output rate. 2 Test system diagram
The test system diagram is shown in Figure 102.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter; 3—Laser power meter; 4—Laser Figure 102
3 Test procedure
3.1 Preheat the laser according to the provisions of the detailed specification. 3.2 Adjust the operating current to maximize the output power of the laser. At this time, the current value read from the ammeter is the optimal operating current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Accuracy of the ammeter and reading error.
4.2 Instability of the laser output power.
4.3 Errors caused by the slow response speed of the laser power meter -s-
SJ20762--1999
Method 103 Test of working voltage [tube voltage drop] The laser measures the potential difference between the two electrodes of the discharge tube at a given working current 2 Test system diagram
Test system diagram Figure 103.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter: 3—High voltage voltmeter: 4—Laser: 5—Laser power meter Figure 103
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 Read the voltage value from the voltmeter at a given working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Measurement error of working current.
4.2 Accuracy and reading error of voltmeter.
niKAoNrkAca
1 Purpose
SJ 20762—1999
Method 104 Test of output power
Measure the laser power output at the output end of the laser at a given working current under specified working conditions. 2 Test block diagram
The test block diagram is shown in Figure 104.
1-Laser power supply; 2-Laser; 3-Laser power meter Figure 104
3 Test procedure
3.1 Preheat the laser according to the provisions of the detailed specification. 3.2 The distance between the receiver of the laser power meter and the output end of the laser shall not be less than 10cm: and it shall be ensured that the laser beam is completely emitted into the receiver.
3.3 Confirm that the laser is working in the specified mode, adjust the current to the given working current, use the power meter to measure the output power of the laser, measure once at a certain interval (greater than the detector return to zero time), measure 5 times in total, and take the average value. 4 Main sources of error
4.1 Accuracy of the power meter and its reading error. 4.2 Influence of non-laser radiation.
1 Self-
SJ 20762-1999
Method 105 Output power test (suitable for high power) Under specified working conditions, measure the laser power output at the output end of the laser at a given working current. 2 Test block diagram
The test block diagram is shown in Figure 105.
1- Laser current stabilizer, 2- Laser: 3- Optical shutter: 4- Attenuator (when necessary): 5- Narrowband filter (when necessary): 6- Laser power meter Figure 105
3 Test procedure
3.1 Preheat the laser according to the detailed specifications. 3.2 Aim the laser power meter probe at the output beam of the laser and make it receive all of it. 3.3 Turn on the laser power meter, select the appropriate range, and calibrate its signature point. 3.4 Read the power meter reading at regular intervals (such as 3 minutes) (before each measurement, make sure that the instrument returns to the initial state), and measure n (n>10) times in total. The output power is calculated as follows: Pa
fsfz h
Where: Pout output power, W;
,- attenuator transmittance, %;
z narrowband filter transmittance, %;
n number of measurements
Pauti output power value measured for the ith time, W. 4 Main sources of error
4.1 Improper use of laser power meter.
4.2 Instrument reading error.
4.3 Error caused by attenuator and narrowband filter, 5 Special requirements
Should be specified in the detailed specifications:
a Accuracy of laser power meter:
b. Allowable error of attenuator and narrowband filter; c. Others.
HKAONrKAca
(105—1)
1 Purpose
SJ 20762—1999
Method 106 Test of output power instability The characteristics of the spot laser output power fluctuation over time (less than 1Hz) within the specified time range. 2 Test block diagram
The test block diagram is shown in Figure 106.
1-Laser current stabilizer: 2-Laser: 3-Attenuator: 4-Photodetector: 5-Impedance conversion linear amplifier; 6-Recording instrument Figure 106
3 Test procedure
3.1 Preheat the laser according to the provisions of the detailed specification. 3.2 Aim the photodetector at the laser beam and turn on the recording instrument. Adjust the recording instrument to the appropriate sensitivity and sampling [recording speed.
3.3 Turn on the entire test system and sample [record] within the specified time range (not less than 1h). Take n (n≥5) values at equal time intervals on the sampling [record 1 curve and calculate the average value. pa
Where: P - the i-th reading on the recording curve, W. 3.4 On the sampling [record 1 curve, find the maximum value P. and the minimum value P.AP = Prmax - Pmin
3.5 Use any of the following formulas to calculate the instability of the output power of the light shield within the specified time range: s
Z(RP)
Where: S, — standard deviation of output power instability, %: P, P—see formula (106--1).
Where: S, — output power instability, %p-
—see formula (106--1).
4p — See formula (106—2).
Note, when indicating that the output power is unstable, the time range must be given, (106--1)
(106—2)
(106—3)
(106—-4)
4Main sources of error
SJ 20762—1999
4.1 Slow response speed of the photodetector, temperature drift, etc. 4.2 Unstable optical attenuator.
4.3 Sampling [recording error of the recording instrument. 4.4 Improper placement of the mechanical device of the test system. 4.5 Influences of ambient temperature fluctuations, airflow and stray light, etc. 5Special requirements
5.1 The photodetector must have high sensitivity and sufficiently fast time response to the light of the received wavelength, and be used under the specified power density without saturation. 5.2 The test system must be linear within the power range. 5.3 Ensure that the recording instrument has sufficient accuracy.5 The test methods for other laser parameters are numbered as 300 series. 3
1 Purpose
SJ 20762—1999
Method 101 Test of ignition voltage When the discharge tube of the laser ignites, measure the voltage between the two electrodes. 2 Test system diagram
The test system diagram is shown in Figure 101.
1-Laser power supply with continuously adjustable voltage: 2-DC ammeter: 3-High voltage voltmeter: 4-Laser discharge tube Figure 101
Note: It is allowed to add a ballast resistor at the anode end of the discharge tube during measurement. 3 Test procedure
3.1 Turn on the power supply, and increase the voltage between the two electrodes of the discharge tube slowly from 0V until the discharge tube ignites. Read the voltage value at the moment of ignition from the voltmeter, which is the ignition voltage. 3.2 Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Differences in the initial state of the gas in the laser tube before ignition. 4.2 How fast or slow the power supply voltage is adjusted.
4.3 Accuracy of the voltmeter and the reading error.
niKAoNrkAca
1 Purpose
SJ20762--1999
Method 102 Test of the optimal operating current
Measure the current value of the laser at the maximum output rate. 2 Test system diagram
The test system diagram is shown in Figure 102.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter; 3—Laser power meter; 4—Laser Figure 102
3 Test procedure
3.1 Preheat the laser according to the provisions of the detailed specification. 3.2 Adjust the operating current to maximize the output power of the laser. At this time, the current value read from the ammeter is the optimal operating current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Accuracy of the ammeter and reading error.
4.2 Instability of the laser output power.
4.3 Errors caused by the slow response speed of the laser power meter -s-
SJ20762--1999
Method 103 Test of working voltage [tube voltage drop] The laser measures the potential difference between the two electrodes of the discharge tube at a given working current 2 Test system diagram
Test system diagram Figure 103.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter: 3—High voltage voltmeter: 4—Laser: 5—Laser power meter Figure 103
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 Read the voltage value from the voltmeter at a given working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Measurement error of working current.
4.2 Accuracy and reading error of voltmeter.
niKAoNrkAca
1 Purpose
SJ 20762—1999
Method 104 Test of output power
Measure the laser power output at the output end of the laser at a given working current under specified working conditions. 2 Test block diagram
The test block diagram is shown in Figure 104.
1-Laser power supply; 2-Laser; 3-Laser power meter Figure 104
3 Test procedure
3.1 Preheat the laser according to the provisions of the detailed specification. 3.2 The distance between the receiver of the laser power meter and the output end of the laser shall not be less than 10cm: and it shall be ensured that the laser beam is completely emitted into the receiver.
3.3 Confirm that the laser is working in the specified mode, adjust the current to the given working current, use the power meter to measure the output power of the laser, measure once at a certain interval (greater than the detector return to zero time), measure 5 times in total, and take the average value. 4 Main sources of error
4.1 Accuracy of the power meter and its reading error. 4.2 Influence of non-laser radiation.
1 Self-
SJ 20762-1999
Method 105 Output power test (suitable for high power) Under specified working conditions, measure the laser power output at the output end of the laser at a given working current. 2 Test block diagram
The test block diagram is shown in Figure 105.
1- Laser current stabilizer, 2- Laser: 3- Optical shutter: 4- Attenuator (when necessary): 5- Narrowband filter (when necessary): 6- Laser power meter Figure 105
3 Test procedure
3.1 Preheat the laser according to the detailed specifications. 3.2 Aim the laser power meter probe at the output beam of the laser and make it receive all of it. 3.3 Turn on the laser power meter, select the appropriate range, and calibrate its signature point. 3.4 Read the power meter reading at regular intervals (such as 3 minutes) (before each measurement, make sure that the instrument returns to the initial state), and measure n (n>10) times in total. The output power is calculated as follows: Pa
fsfz h
Where: Pout output power, W;
,- attenuator transmittance, %;
z narrowband filter transmittance, %;
n number of measurements
Pauti output power value measured for the ith time, W. 4 Main sources of error
4.1 Improper use of laser power meter.
4.2 Instrument reading error.
4.3 Error caused by attenuator and narrowband filter, 5 Special requirements
Should be specified in the detailed specifications:
a Accuracy of laser power meter:
b. Allowable error of attenuator and narrowband filter; c. Others.
HKAONrKAca
(105—1)
1 Purpose
SJ 20762—1999
Method 106 Test of output power instability The characteristics of the spot laser output power fluctuation over time (less than 1Hz) within the specified time range. 2 Test block diagram
The test block diagram is shown in Figure 106.
1-Laser current stabilizer: 2-Laser: 3-Attenuator: 4-Photodetector: 5-Impedance conversion linear amplifier; 6-Recording instrument Figure 106
3 Test procedure
3.1 Preheat the laser according to the provisions of the detailed specification. 3.2 Aim the photodetector at the laser beam and turn on the recording instrument. Adjust the recording instrument to the appropriate sensitivity and sampling [recording speed.
3.3 Turn on the entire test system and sample [record] within the specified time range (not less than 1h). Take n (n≥5) values at equal time intervals on the sampling [record 1 curve and calculate the average value. pa
Where: P - the i-th reading on the recording curve, W. 3.4 On the sampling [record 1 curve, find the maximum value P. and the minimum value P.AP = Prmax - Pmin
3.5 Use any of the following formulas to calculate the instability of the output power of the light shield within the specified time range: s
Z(RP)
Where: S, — standard deviation of output power instability, %: P, P—see formula (106--1).
Where: S, — output power instability, %p-
—see formula (106--1).
4p — See formula (106—2).
Note, when indicating that the output power is unstable, the time range must be given, (106--1)
(106—2)
(106—3)
(106—-4)
4Main sources of error
SJ 20762—1999
4.1 Slow response speed of the photodetector, temperature drift, etc. 4.2 Unstable optical attenuator.
4.3 Sampling [recording error of the recording instrument. 4.4 Improper placement of the mechanical device of the test system. 4.5 Influences of ambient temperature fluctuations, airflow and stray light, etc. 5Special requirements
5.1 The photodetector must have high sensitivity and sufficiently fast time response to the light of the received wavelength, and be used under the specified power density without saturation. 5.2 The test system must be linear within the power range. 5.3 Ensure that the recording instrument has sufficient accuracy.1. Turn on the power supply and slowly increase the voltage between the two electrodes of the discharge tube from 0V until the discharge tube ignites. The voltage value at the moment of ignition is read from the voltmeter, which is the ignition voltage. 3.2 Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Differences in the initial state of the gas in the laser tube before ignition. 4.2 Adjust the speed of the power supply voltage.
4.3 Accuracy and reading error of voltmeter.
niKAoNrkAca
1 Purpose
SJ20762-—1999
Method 102 Test of optimal operating current
Measure the current value of the laser when it outputs maximum rate. 2 Test system diagram
The test system diagram is shown in Figure 102.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter; 3—Laser power meter; 4—Laser Figure 102
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 Adjust the working current to maximize the output power of the laser. At this time, the current value read from the ammeter is the optimal working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Accuracy of ammeter and reading error.
4.2 Instability of laser output power.
4.3 Errors caused by slow response speed of laser power meter -s-
SJ20762--1999
Method 103 Test of working voltage [tube voltage drop] Under a given working current, the laser measures the potential difference between the two electrodes of the discharge tube 2 Test system diagram
Test system diagram Figure 103.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter: 3—High voltage voltmeter: 4—Laser: 5—Laser power meter Figure 103
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 At a given operating current, read the voltage value from the voltmeter. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Measurement error of working current.
4.2 Accuracy and reading error of voltmeter.
niKAoNrkAca
1 Purpose
SJ 20762—1999
Method 104 Output power test
Under specified working conditions, measure the laser power output at the output end of the laser at a given working current. 2 Test block diagram
The test block diagram is shown in Figure 104.
1 - Laser power supply; 2 - Laser; 3 - Laser power meter Figure 104
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 The distance between the receiver of the laser power meter and the laser output end shall not be less than 10cm: and it should be ensured that the entire laser beam enters the receiver.
3.3 Confirm that the laser is working in the specified mode, adjust the current to the given working current, and use a power meter to measure the output power of the laser. Measure once every certain period of time (greater than the detector zero return time), measure 5 times in total, and take the average value. 4 Main sources of error
4.1 Accuracy of the power meter and errors in its readings. 4.2 Effects of non-laser radiation.
1
SJ 20762-1999
Method 105 Output power test (suitable for high power) Under specified working conditions, measure the laser power output at the output end of the laser at a given working current. 2 Test block diagram
The test block diagram is shown in Figure 105.
1—Laser regulated current power supply, 2—Laser: 3—Optical shutter: 4—Attenuator (when necessary): 5—Narrowband filter (when necessary): 6 Laser power meter Figure 105
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 Aim the laser power meter probe at the output beam of the laser and allow it to be fully received. 3.3 Turn on the power of the laser power meter, select the appropriate range, and calibrate its signature point. 3.4 Read the power meter reading once at a certain interval (such as 3 minutes) (before each measurement, make sure the instrument returns to the initial state), and measure n (n>10) times in total. The output power is calculated according to the following formula: Pa
fsfz hsi
Where: Pout output power, W;
,- attenuator transmittance, %;
z narrowband filter transmittance, %;
n measurement number
Pauti the output power value measured for the ith time, W. 4 Main sources of error
4.1 Improper use of laser power meter.
4.2 Instrument reading error.
4.3 Errors caused by attenuators and narrow-band filters, 5 Special requirements
Should be specified in the detailed specifications:
a Accuracy of laser power meter:
b. Allowable error of attenuators and narrowband filters; c. other.
HKAONrKAca
(105—1)
1Purpose
SJ 20762—1999
Method 106 Test of output power instability Within a specified time range, the characteristics of the spot laser output power fluctuation over time (less than 1Hz) are measured. 2 Test block diagram
The test block diagram is shown in Figure 106.
1-Laser regulated current power supply: 2-Laser: 3-Attenuator: 4-Photodetector: 5-Impedance transformation linear amplifier; 6-Recording instrument Figure 106
3 Test procedure
3.1 Preheat the laser as specified in the detailed specifications. 3.2 Aim the photodetector at the laser beam and turn on the recording instrument. Adjust the recording instrument to the appropriate sensitivity and sampling rate.
3.3 Turn on the entire test system and take samples [record] within the specified time range (not less than 1h). Take n (n≥5) values at equal time intervals on the sampling [record 1 curve and calculate the average value. pa
Where: P - the i-th reading on the recording curve, W. 3.4 On the sampling [record 1 curve, find the maximum value P. and the minimum value P.AP = Prmax - Pmin
3.5 Use any of the following formulas to calculate the instability of the light shielding device's output power within the specified time range: s
Z(RP)
Wherein, S, — standard deviation of output power instability, %: P, P—see formula (106--1).
Where: S, —output power instability, %p-
—see formula (106-1).
4p — See formula (106—2).
Note, when indicating that the output power is unstable, the time range must be given, (106--1)
(106—2)
(106—3)
(106—-4)
4Main sources of error
SJ 20762—1999
4.1 Slow response speed of photodetector, temperature drift, etc. 4.2 The optical attenuator is unstable.
4.3 Sampling of recording instruments [Recording error. 4.4 The mechanical device of the test system is improperly set up. 4.5 Influences of ambient temperature fluctuations, airflow and stray light. 5 Special requirements
5.1 The photodetector must have high sensitivity and sufficiently fast time response to the light of the received wavelength and be used under the specified power density without saturation. 5.2 The test system must be linear within the measured power range. 5.3 Ensure sufficient accuracy of the recording instrument.
- 10 -
iKAoNrKAca-1. Turn on the power supply and slowly increase the voltage between the two electrodes of the discharge tube from 0V until the discharge tube ignites. The voltage value at the moment of ignition is read from the voltmeter, which is the ignition voltage. 3.2 Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Differences in the initial state of the gas in the laser tube before ignition. 4.2 Adjust the speed of the power supply voltage.
4.3 Accuracy and reading error of voltmeter.
niKAoNrkAca
1 Purpose
SJ20762-—1999
Method 102 Test of optimal operating current
Measure the current value of the laser when it outputs maximum rate. 2 Test system diagram
The test system diagram is shown in Figure 102.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter; 3—Laser power meter; 4—Laser Figure 102
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 Adjust the working current to maximize the output power of the laser. At this time, the current value read from the ammeter is the optimal working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Accuracy of ammeter and reading error.
4.2 Instability of laser output power.
4.3 Errors caused by slow response speed of laser power meter -s-
SJ20762--1999
Method 103 Test of working voltage [tube voltage drop] Under a given working current, the laser measures the potential difference between the two electrodes of the discharge tube 2 Test system diagram
Test system diagram Figure 103.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter: 3—High voltage voltmeter: 4—Laser: 5—Laser power meter Figure 103
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 At a given operating current, read the voltage value from the voltmeter. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Measurement error of working current.
4.2 Accuracy and reading error of voltmeter.
niKAoNrkAca
1 Purpose
SJ 20762—1999
Method 104 Output power test
Under specified working conditions, measure the laser power output at the output end of the laser at a given working current. 2 Test block diagram
The test block diagram is shown in Figure 104.
1 - Laser power supply; 2 - Laser; 3 - Laser power meter Figure 104
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 The distance between the receiver of the laser power meter and the laser output end shall not be less than 10cm: and it should be ensured that the entire laser beam enters the receiver.
3.3 Confirm that the laser is working in the specified mode, adjust the current to the given working current, and use a power meter to measure the output power of the laser. Measure once every certain period of time (greater than the detector zero return time), measure 5 times in total, and take the average value. 4 Main sources of error
4.1 Accuracy of the power meter and errors in its readings. 4.2 Effects of non-laser radiation.
1
SJ 20762-1999
Method 105 Output power test (suitable for high power) Under specified working conditions, measure the laser power output at the output end of the laser at a given working current. 2 Test block diagram
The test block diagram is shown in Figure 105.
1—Laser regulated current power supply, 2—Laser: 3—Optical shutter: 4—Attenuator (when necessary): 5—Narrowband filter (when necessary): 6 Laser power meter Figure 105
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 Aim the laser power meter probe at the output beam of the laser and allow it to be fully received. 3.3 Turn on the power of the laser power meter, select the appropriate range, and calibrate its signature point. 3.4 Read the power meter reading once at a certain interval (such as 3 minutes) (before each measurement, make sure the instrument returns to the initial state), and measure n (n>10) times in total. The output power is calculated according to the following formula: Pa
fsfz hsi
Where: Pout output power, W;
,- attenuator transmittance, %;
z narrowband filter transmittance, %;
n measurement number
Pauti the output power value measured for the ith time, W. 4 Main sources of error
4.1 Improper use of laser power meter.
4.2 Instrument reading error.
4.3 Errors caused by attenuators and narrow-band filters, 5 Special requirements
Should be specified in the detailed specifications:
a Accuracy of laser power meter:
b. Allowable error of attenuators and narrowband filters; c. other.
HKAONrKAca
(105—1)
1Purpose
SJ 20762—1999
Method 106 Test of output power instability Within a specified time range, the characteristics of the spot laser output power fluctuation over time (less than 1Hz) are measured. 2 Test block diagram
The test block diagram is shown in Figure 106.
1-Laser regulated current power supply: 2-Laser: 3-Attenuator: 4-Photodetector: 5-Impedance transformation linear amplifier; 6-Recording instrument Figure 106
3 Test procedure
3.1 Preheat the laser as specified in the detailed specifications. 3.2 Aim the photodetector at the laser beam and turn on the recording instrument. Adjust the recording instrument to the appropriate sensitivity and sampling rate.
3.3 Turn on the entire test system and take samples [record] within the specified time range (not less than 1 hour). Take n (n≥5) values at equal time intervals on the sampling [record 1 curve and calculate the average value. pa
Where: P - the i-th reading on the recording curve, W. 3.4 On the sampling [record 1 curve, find the maximum value P. and the minimum value P.AP = Prmax - Pmin
3.5 Use any of the following formulas to calculate the instability of the light shielding device's output power within the specified time range: s
Z(RP)
Wherein, S, — standard deviation of output power instability, %: P, P—see formula (106--1).
Where: S, —output power instability, %p-
—see formula (106-1).
4p — See formula (106—2).
Note, when indicating that the output power is unstable, the time range must be given, (106--1)
(106—2)
(106—3)
(106—-4)
4Main sources of error
SJ 20762—1999
4.1 Slow response speed of photodetector, temperature drift, etc. 4.2 The optical attenuator is unstable.
4.3 Sampling of recording instruments [Recording error. 4.4 The mechanical device of the test system is improperly set up. 4.5 Influences of ambient temperature fluctuations, airflow and stray light. 5 Special requirements
5.1 The photodetector must have high sensitivity and sufficiently fast time response to the light of the received wavelength and be used under the specified power density without saturation. 5.2 The test system must be linear within the measured power range. 5.3 Ensure sufficient accuracy of the recording instrument.
- 10 -
iKAoNrKAca-2 Adjust the working current to maximize the output power of the laser. The current value read from the ammeter at this time is the optimal working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Accuracy of the ammeter and reading error.
4.2 Instability of the laser output power.
4.3 Errors caused by the slow response speed of the laser power meter -s-
SJ20762--1999
Method 103 Test of working voltage [tube voltage drop] The laser measures the potential difference between the two electrodes of the discharge tube at a given working current. 2 Test system diagram
Test system diagram Figure 103.
1—Laser power supply with continuously adjustable voltage: 2—DC ammeter: 3—High voltage voltmeter: 4—Laser: 5—Laser power meter Figure 103
3 Test procedure
3.1 Preheat the laser according to the provisions of the detailed specification. 3.2 Read the voltage value from the voltmeter at a given working current. Repeat the measurement five times and take the average value. 4 Main sources of error
4.1 Measurement error of working current.
4.2 Accuracy of voltmeter and reading error.
niKAoNrkAca
1 Purpose
SJ 20762—1999
Method 104 Output power test
Measure the laser power output at the output end of the laser at a given working current under specified working conditions. 2 Test block diagram
The test block diagram is shown in Figure 104.
1-Laser power supply; 2-Laser; 3-Laser power meter Figure 104
3 Test procedure
3.1 Preheat the laser as specified in the detailed specification. 3.2 The distance between the receiver of the laser power meter and the output end of the laser shall not be less than 10cm: and it should be ensured that the laser beam is completely emitted into the receiver.
3.3 Confirm that the laser is working in the specified mode, adjust the current to the given working current, use the power meter to measure the output power of the laser, measure it once every certain time (greater than the detector return to zero time), measure it 5 times in total, and take the average value. 4 Main sources of error
4.1 Accuracy of the power meter and its reading error. 4.2 Influence of non-laser radiation.
1 Self-
SJ 20762-1999
Metho
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