Gain Clamping in Two-Stage L-Band EDFA Using a Broadband FBG
Document Type
Article
Publication Date
1-1-2004
Abstract
A gain-clamped long wavelength band erbium-doped fiber amplifier (L-band EDFA) with an improved gain characteristic is demonstrated by simply adding a broadband conventional band (C-band) fiber Bragg grating (FBG) in a two-stage amplifier system. The FBG reflects backward C-band amplified spontaneous emission (ASE) from the second stage back into the system to clamp the gain. The gain is clamped at about 22.4 dB with a gain variation below 0.4 dB for input signal powers of -40 to -15 dBm. Compared with an unclamped amplifier of similar noise figure values, the small signal gain has improved by 2.4 dB due to the FBG which blocks the backward propagating ASE. At wavelengths from 1570 to 1600 nm, gain of the clamped amplifier varies from 19.4 to 26.7 dB. The corresponding noise figure varies by ±0.35 dB around 5 dB, which is not much different compared to that of the undamped amplifier.
Keywords
Fiber Bragg grating (FBG), Gain clamping, L-band EDFA, Optical amplifier, Two-stage EDFA
Divisions
fac_eng,PHYSICS
Publication Title
IEEE Photonics Technology Letters
Volume
16
Issue
2
Publisher
Institute of Electrical and Electronics Engineers (IEEE)