Performance Enhancement for Wavelength Converters by Using an Assisted beam

• Main Authors: Gong Pei-Miin, 龔佩敏
• Other Authors: Lee San-Liang
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/07392767095078784843

碩士 === 國立臺灣科技大學 === 電子工程系 === 90 === We propose to use an additional injection beam of short wavelength to enhance the performance of wavelength conversion that utilizes the four-wave-mixing effect in a semiconductor optical amplifier (SOA). First, we establish a sophisticated model that includes both the spatial and spectral dependency of amplified spontaneous emission (ASE) in a SOA to simulate the effects of the assisted beam on the conversion efficiency and signal-to-background-noise ratio (SBR). The simulation predicts the correct trends of how an assisted beam affects the characteristics of a SOA or a wavelength converter. It also indicates that the transparent current of the assisted beam may not be measured from the crossover point of the gain curves due to the ASE contribution. The simulation proves that using a shorter-wavelength assisted beam and a longer SOA is the key for obtaining better wavelength conversion. The experiments demonstrate about 4.6dB and 5.8dB improvement on the saturation power and conversion efficiency, respectively, for applying a 1480nm assisted beam when the SOA is biased at the corresponding transparent condition for the assisted beam. We also demonstrate that the improvement becomes smaller as the SOA is biased at the gain region for the assisted beam, but the SBR is better. Using a shorter-wavelength assisted beam (1430nm) can have better enhancement on conversion efficiency as the SOA is biased at high-injection level. The bit-error-rate measurements also prove that an assisted beam can decrease the power penalty caused by the wavelength conversion process because it can improve SBR. In order to enhance the effects of the assisted beam, this work suggests decreasing the internal loss of a SOA, using a longer SOA, and using a shorter-wavelength assisted beam.