Very simple method to stabilise modelocked erbiumfibre lasers

Abstract
A very simple method is proposed and demonstrated to stabilise an actively modelocked erbium fibre laser with a nonpolarisation maintaining cavity. This method is based on the detection of differential growth rates of noise at different frequencies, which is then used to control cavity length. The whole control circuit is composed of low frequency analogue electronics and no computer is needed. A fibre laser stabilised by this method demonstrated very stable BER performance at 10 bit/s.