Semiconductor Laser Characteristics Parameter Measurement System Design And Development

With the development of technics, It is getting more perfect in manufacturing LD and getting more cheaper in cost of it, LD has been widely used in many field such as optical fiber communication, measurement technic, distance measurement by laser, micro-machining, radar imaging by laser, medical treatment, bioengineering and so on, in these field, users are getting more care about the feature of LD. There are many devices that can measure the idiocratic parameter of LD at the present time, but these devices are different on the LD varieties that can be measured and precision that the device can reach. In this kind of product, the products that occupy great proportion is foreign product, and its measurement precision is higher, but it has higher price. Only the professional company is able to equip this kind of measurement device, but to general user, because of its higher price the device can not be used widely, so it limits our research on LD greatly. So it is becoming more significantly to develop an new device that can is not only precise in measurement but also easy to use.The general parameter of LD is include threshold feature, optical spectrum feature, optical intensity distribution, output power and conversion efficiency, temperature and thermal resistance and so on.At the present day, in domestic field, there are some way on the measurement of LD's parameter , one of them is called 'testing independently', another way to measure is through the use of 'automatic testing system 'in CAS, and these testing system has the high testing precision, but the system are very huge in size, difficult to operate, has a long testing period, and are higher in price, and it is easy to hurt the LD because of its long testing period. This kind of device that made by foreign country, largely are small in size, easy to carry, has a more short testing period, and not easy to hurt the LD, but this kind of foreign device is too costly to buy them to some company and research institution. So these kinds of device is very difficult to used widely and then it limit the research and development on the LD greatly.According to the present market condition, we develop an new device successfully with lower cost, it can measure the important parameter of LD precisely and our device is easy to use, we can get the idiocratic curve of LD by processing the data we got from our testing devive, such as voltage-current curve,optical power-current curve, also we can evaluate the performance of LD we have tested according the curve we got.Semiconductor Laser is a kind of device which is only work above some value. It has two important parameters, which are threshold and power-current characteristic, it will be very useful to measure this two parameter curve, this will help you understand semiconductor laser very much. When the current driving LD is lower than threshold current, the optical power outputted will be a few, and the output light now is called fluorescence; When the driving current reaches threshold current, the output optical power will increase rapidly ,and now the output light is laser. The work current of LD can not be in excess of rated current. So we know if we need laser, the driving current in LD must be in excess of threshold current, but at the same time, the value of the work current should be below that of rated current, or LD will be destroyed easily.Firstly our device can measure parameter of some representative LD, include Voltage-Current Feature, Optical Power -Current Feature and so on, our system are made up of input-output circuit based on microchip system. When the system is on work, under the driving of power whose current is invariance, the LD can work atdifferent point through adjusting parameter of circuit, then sample these different work point and convert analog voltage to digital data, that is doing A/D convert, and put these data into cpu, after the process of cpu, the data will be displayed on crystal screen.Because the short development time, we have to time to write the program on PC part, but we have finished...