Applications and Discussion of Semiconductor Optical Amplifier

• Main Authors: Weng,chun-chia, 翁俊嘉
• Other Authors: Tsai,Wen-Shing
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/58204042344134845906

碩士 === 明志科技大學 === 電機工程研究所 === 99 === The actual channel number of wavelength Division Multiplexing (WDM) system is still far fewer than the number of the nodes and users. The wavelength blocking happens due to wavelength competition when two optical network units have the same wavelength channel. Wavelength conversion (WC) is one of the key techniques to resolve this problem. It can enhance the flexibility and extension of the network, and provide better operation and management of the network. Semiconductor optical amplifier (SOA) has many nonlinear effects included Cross-gain Modulation (XGM), Cross-phase Modulation (XPM) and four-wave mixing (FWM). The nonlinear characteristics are suitable for wavelength conversion. The SOA has many benefits such as large bandwidth and small bulk that is suitable for batch production. A detailed theory research of several nonlinear effects and application of SOA are given. This study presents some approach to generate wavelength conversion based on nonlinear effects in a SOA. In first architecture we present a detailed experimental characterization of SOA-based wavelength conversion for conversion signals. The optical signal to noise ratio (OSNR) of the output converted signal and FWM efficiency are studied at a fixed value of wavelength detuning between the pump and the signal. Then, the effect of wavelength detuning between signal and pump is experimentally investigated. Finally conversion signal measurements are performed at different Signal-to-Pump power ratio (SPR) and OSNR compared with optimum FWM conversion efficiency. In second architecture we proposed a full-duplex Radio-over-Fiber (ROF) system. The optical carrier suppression (OCS) modulation scheme is employed to generate optical mm-wave and up-convert application. Up-conversion shows the highest receiver sensitivity, highest spectral efficiency and smallest power penalty over ROF system delivery. Moreover, the OCS modulation scheme has a simple configuration and low-frequency bandwidth requirement for electrical and optical components. We designed and experimentally demonstrated an efficient photonic frequency-sextuple technology for 41.4 GHz ROF systems to simultaneously realize millimeter-wave (mm-wave), and microwave generation for down-stream channels. A filter is employed to separate the optical carrier from the sidebands to generate optical microwave carrier for up-stream channel. The third architecture is present a scheme of up-converting optical intermediate frequency (IF) signals with an optical local oscillator (LO) using XGM effect in a SOA. This scheme provides high conversion efficiency and is independent of the incident light wavelength and polarization. It can be useful for ROF transmission system application.