Design of Broad Band and Gain Flattened Dispersion Compensating Raman/Erbium Doped Fiber Hybrid Amplifiers with All-Optical Gain-Clamped for WDM Systems

• Main Authors: You-Ren Jian, 簡佑任
• Other Authors: Jeng-Cherng Dung
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/76832515025912033936

碩士 === 國立東華大學 === 光電工程研究所 === 96 === In this thesis, we design dispersion-compensated Raman/erbium-doped fiber hybrid amplifiers recycling residual Raman pump for wavelength-division multiplexing (WDM) systems. The hybrid amplifiers system only require single Raman pump source. The experimental results showed that the hybrid amplifiers scheme have net gain of more than 17 dB which provide gain bandwidth over 70 nm from 1525 to 1595 nm for input signal power of -20 dBm. Compared with the conventional dispersion-compensated Raman amplifiers (DCRA), the net gain increases 4.36 dB and the gain bandwidth broadens 50 nm. Besides, there is no significant increase of noise figure (NF) in our experimental setup. The NF is about 6.79 dB. In order to increase gain bandwidth and to flatten gain of the hybrid amplifiers. We used multiple wavelengths Raman pump units to pump the Raman fiber amplifiers. The gain ripple of less than ±1.47 dB can be achieved over 65 nm from 1525 to 1590 nm by the optimal combination of pump wavelength at 1435 and 1480 nm. The gain bandwidth is over 80 nm at a wavelength range of 1520 to 1600 nm. The net gain and NF are 20.01 dB and 5.74 dB for input signal power of -20 dBm, respectively. The all-optical gain clamped technique is a simple and effective way to achieve constant gain characteristics regardless of input signal power variations. To our knowledge, this is the first experimentally demonstration gain-clamped broad band and gain flattened dispersion-compensated Raman/erbium-doped fiber hybrid amplifiers by recycling residual Raman pump with only using a single FBG for WDM systems. The optimum gain clamped wavelength is 1564 nm. The gain variation of less than 0.21 dB can be achieved over 100 nm from 1525 to 1625 nm and the dynamic signal input exceed 18 dBm ranging from -20 to -2 dBm. Besides, the gain ripple of less than ±1.75 dB is achievable over 65 nm from 1530 to 1595 nm. The gain bandwidth is over 80 nm from 1520 to 1600 nm. This hybrid amplifiers system has the advantages of the high transmission capacity, high gain, low noise, broad gain bandwidth, high flattened gain and large dynamic range of input power.