Gain clamped L‐band EDFA using a fiber Bragg grating in two stage configuration

A gain clamping technique for the long‐wavelength‐band erbium‐doped fiber amplifier (L‐band EDFA) is presented. It uses two circulators and a fiber Bragg grating (FBG) to route a backward amplified spontaneous emission (ASE) from a second‐stage amplifier and launch it back into the first stage. The use of a broadband (BB) FBG has shown a better gain clamping effect, compared to a narrowband (NB) FBG. The amplifier gain for the BB FBG set up is clamped at 15.0 dB with a gain variation of less than 0.1 dB for an input power as high as −5 dBm. The use of a BB FBG has also flattened the gain spectrum. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 265–266, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10889