Phase-locking of two photonic crystal fibre lasers by mutual injection scheme

A simple and compact scheme for the phase-locking of two photonic crystal fibre (PCF) lasers is presented and studied experimentally. In the experiments, the two PCF lasers are mutually injected by direct transmission coupling of the fibre lasers. The interference strips are of high contrast ratio and stability even in high power operation. 39W coherent output power is obtained with combining efficiency of 97.2%.