Research On High-power High-brightness Semiconductor Lasers

Semiconductor lasers are widely used in the military, industry, avigation and spaceflight and otherwise in our state key areas. The broad area semiconductor lasers have the advantages of simple process, high output power, high electrical to optical conversion efficiency and high reliable quality and son on, which have been a major device used in areas of relevant application and are also the main investigated device type. But beam quality of slow axis is easily affected by space burned hole, self-focusing and thermal lens effect, which lead to big slow axis divergent angle under high output power. These are a serious bad impacts on the slow axis beam quality, and the relevant area of application and development have been restricted.This paper has studied the main characters of broad area semiconductor laser. The main content and results are as follows:1. Output characteristic on all kinds of semiconductor lasers have been summarized and analysed, physical factors have been gain for super-luminent output, which have been afforded to design and preparation.2. Basic physical models of broad area high power semiconductor lasers have been created, and theory analysis and preliminary calculation have been processed. Main methods and design principles have been compared to increase output power on broad area semiconductor lasers, results of which have been obtained to improve beam quality of high power semiconductor. Beam diffusing property and mechanism of muti-mode have been analysed. From material wafe design, technics of device structural design to discuss the relations of power, beam quality and superluminente.3. Technics of super-luminence broad area high power semiconductor laser have been processed for basic techniques and theory, including wafer structural design, facture technics and so on. And ohm contact, cavity coating, nitrogen passivation have been designed and factured, which are particular investigated. The unsymmetry grads structral wide cavity wafer has been designed, vertical directional beam quality and series resistance have been improved. AlN cavity surface coating technics, nitrogen passivation have been applied for the first time, which have been combined with AuSn solder to improve the thermal characteristic and ability of high power output of broad area semiconductor lasers, and highest ouput power(cavity length 1mm, injection region width 100μm) is up to 3.5 W from 2 W,75% COD ability enhanced.4.808 nm AIGaAs/ GaAs broad area super-luminence semiconductor lasers with a mode filter has been developed for the first time in the country. According to light field simulation for slow axis divergente angle of narrow stripe semiconductor laser, single quanta well wafer has been introduced, broad area semiconductor lasers with a mode filter in different position (cavity length 1 mm. mode filter size 100×500μm) have been designed and preparation, P-I, ohm and beam characteristic have been compared and analysised. The position of mode filter is suitable for best mode characteristic. The highest output power is up to 3 W under continue wave operation; The slow axis divergence angle is 3.3°when output power is up to 2.5 W, whose luminence is three times of traditional device. The structure with non-absorb mode filter has been optimized, whose character temperature has been up to 154 K of new device from 115 K of traditional device.