Fast tunable lasers for optical switching networks

• Main Authors: Ching Yun Chien, 簡清雲
• Other Authors: San Liang Lee
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/07118228040934103765

碩士 === 國立臺灣科技大學 === 電子工程系 === 91 === In this thesis, a fast wavelength tunable transmitter using a three-section DBR laser has been demonstrated. The transmitter can provide 4 wavelength channels of 100GHz channel spacing with a switching time <10ns and a wavelength stability batter than ±1GHz. The DBR laser needs to be biased at lower bias current injection to reduce the effects of asymmetric gain. During the transition between two wavelength channels, the hysteresis effect due to the asymmetric gain spectrum can be minimized. Therefore, the wavelength stability and accuracy of each channel can be improved. A simulation model for three-section DBR lasers was developed to investigate the factors that influence the wavelength tuning performance. We clarified the origins of the hysteresis effects and points out the measures to reduce the effects. The simulation approach can also be applied to other tunable laser structures. We use a high-speed digital-analog converter with current output mode to simultaneously drive the phase section and grating section of a DBR laser. A PC-based remote control program was used to set the current output and a static random access memory stored the wavelength map. An automatic measurement setup was designed to record the tuning map. The time-solved techniques were used to measure the dynamic response in wavelength tuning. We proved that fast tunable lasers that meet the requirements of optical packet or burst switching can be realized by carefully designing the laser structure and choosing the appropriate operation conditions.