Progress in Electrically Tunable Semiconductor Laser with a Liquid Crystal Spatial Light Reflector

• Main Authors: WenLi Lu, 呂文禮
• Other Authors: C. L. Pan
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/31147745558936876554

碩士 === 國立交通大學 === 光電工程所 === 87 === In this thesis, we improved the tunable external-cavity semiconductor laser diode system which was developed by ourselves. The external cavity consists of a grazing-incidence grating, lens, liquid crystal spatial light reflector, and a semiconductor laser as the gain medium . The system can be operated in single、dual or multi-wavelength mode when we use the electronic-controlled liquid crystal spatial light reflector . The liquid crystal spatial light reflector we use is a TN cell. The laser system can output fifty wavelengths by controlled the liquid crystal spatial light reflector electronically. The response time of the cell is 54.6ms. The reflection ratio is 43﹪. When we used a anti-reflection coating red laser diode （center wavelength is 657nm）as the gain medium, the tuning range of the wavelength was 10.4 nm （limited by LC cell）（I=1.54Ith）. The side-mode-suppression-ratio（SMSR）of the laser was batter tnan 25 dB throughout this range. When we used a near infrared laser diode （center wavelength is 832nm）as the gain medium, the output power of the laser can achieve several tens of miniwatts. The tuning range of the wavelength is 8.12nm（limited by LC cell）. The SMSR of the laser was better than 25 dB throughout this range.