Design of All-Optical Gain-Clamped Erbium-Doped Fiber Amplifiers
In this paper, we investigate the optimal design of optically gain-clamped (GC) erbium-doped fiber amplifier (EDFA). Three configurations under discussion, the first uses two optical circulators (OC), one optical band pass filter (OBPF), and one variable optical attenuator (VOA), to form ring cavity. Such ring cavity can regulate itself: when the channel numbers increase, the amounts of optical feedback decrease; contrarily, when the channel numbers decrease, the amounts of optical feedback increase. So it has the gain-clamped ability. The second employs one or double fiber Bragg grating (FBG) to reflect the residual Amplified Spontaneous Emission (ASE) for regulating the signal gain, such configurations have the same self-regulation as before. The choice of center wavelength and bandwidth of FBG can control the signal gain to reach the optimal gain and fairly low noise figure (NF). The third configuration is similar to the first; the difference is that the third with figure-8 cavity, which uses a common OBPF and VOA, can regulate the gain of C- and L-bands at the same time. The choice of OBPF is just located within the dead-zone between the C- and L-bands, where no WDM channels can be transmitted. If we choose suitable loop attenuation, we can get an equal signal gain of C- and L-bands¡¦ channels.
Advisor:Kai-Ming Feng; Tsair-Chun Liang; Sheng-Lung Huang; Yi-Jen Chiu; Yung-Kuang Chen
School:National Sun Yat-Sen University
School Location:China - Taiwan
Source Type:Master's Thesis
Keywords:gain clamping edfa
Date of Publication:06/14/2003