Study On Semiconductor Laser Comprehensive Parameter Test Method And Components

The quality of the laser diode (LD) depends on its characteristic parameters. In every field of application, the user needs to choose the LD according to their own needs, so it is necessary to know the indicators about the characteristic parameters of the LD. So this topic is about the study of LD parameters test method and LD components, providing the necessary technical basis to LD parameter test equipment industry.LD components are the necessary devices in LD work except the LD chip, LD drive power as one of the components of LD plays an important role in work of LD. Design of a new type of LD drive power supply which has widely used at present on the basis of the traditional LD drive power supply with high efficiency, large range of constant current and other characteristics.In this paper, the system introduced the test method of the LD integrated parameters, and did a test about the thermal characteristic of LD, concluded and summarized the thermal characteristics of the LD. With the temperature of LD higher the slope efficiency of PI curve decreases, external differential quantum efficiency is reduced, the value of threshold current become higher, the red shift occured on spectral curves, the peak wavelength is longer, the divergence angle of far-field becomes bigger and beam quality becomes worse. The wavelength temperature coefficient k is obtained by experimental tests, using wavelength redshift method to calculate the thermal resistance of the LD, the results show that the thermal resistance changes over the current change range. As a result, the measurement of thermal resistance needs given specific test conditions, or with thermal resistance in different drive current interval statistics to measure the average thermal resistance properties.The far field reflects the LD beam intensity distribution on the space geometry. This article mainly aims at the disadvantage of high cost in the traditional LD far field test, the far field test method by scanning legal angle is found. Using the single-chip microcomputer control level and vertical motor, firstly, the motor with photoelectric detector sweep of LD a spindle, get a2D light intensity distribution, then the motor turning with LD in vertical surface, the photoelectric detector scanning a two-dimensional light intensity distribution when turning a degree angle, so when the stepping motor turned90degrees, we can get the LD of another spindle distribution. If the photoelectric detector turns180degree angle, we can get a180/a+1of2D light intensity distribution. Combed with the MATLAB software we can draw the3D light intensity distribution of LD to complete the far field test ofLD.The design of hardware includes51single-chip microcomputer control module, the photoelectric conversion module, L298N motor driver module, ADC0832modulus conversion module, LD drive power supply module and the current display module. The design of program contains three parts programs of serial communication, stepping motor driver and modulus conversion. LD power supply module and display module is responsible for providing LD current drive current and displaying the current, motor driver module can turn some degree with the LD and photoelectric detector, the photoelectric conversion module is responsible for the optical signal is converted to electrical signals, transfer the data to PC through the ADC module and serial communication module, drawing into three-dimensional distribution of light intensity with the software of MATLAB for testers to analyze the beam quality.