Multiwavelength erbium-doped fibre laser based on a high-birefringence fibre loop mirror

A novel multiwavelength fibre laser is proposed, which is based on a fibre loop mirror formed by a high-birefringence (HiBi) fibre, a polarisation con troller, and a directional coupler. By setting the polarisation controller properly, the HiBi fibre loop mirror acts as a polarisation-independent wav elength filter. With this configuration, the wavelength spacing of the lase r can be varied accurately by adjusting the length of the HiBi fibre. Exper imentally, by cooling the erbium-doped fibre with liquid nitrogen to reduce its homogeneous linewidth, stable emission at 16 wavelengths with a spacin g of 0.8nm and an amplitude variation of < 5dB was achieved.