Gain‐clamping in L‐band zirconium–erbium co‐doped fiber amplifier with FBG based lasing control

Abstract

AbstractIn this study, gain clamping performance in an L‐band zirconium‐erbium co‐doped fiber amplifier (Zr‐EDFA) with a very short length of heavily doped fiber and FBG based lasing control structure was presented. A simple gain clamping design based on a symmetrical narrow band C‐band fiber Bragg grating (FBG) pair addition was used in the L‐band Zr‐EDFA with bidirectionally pumping scheme. An L‐band gain of higher than 25 dB was obtained with a maximum noise figure (NF) of 5 dB in the conventional Zr‐EDFA design which was higher than the previous results obtained with forward pumping scheme. When a couple of narrow band FBGs at Bragg reflection wavelength of 1542 nm are used as the lasing mechanism for gain clamping in L‐band operation, small signal gain of Zr‐EDFA decreases, but on the other hand, the gain is clamped at almost 15.5 dB with a flattened gain spectrum along a dynamic range of 25 dB for the signal input powers between −30 and −5 dBm with the expense of 1.5 dB NF penalty.