Design of a multi-wavelength fibre laser using an intra-cavity phase modulator and Sagnac loop filter for sensor applications

Abstract

This paper describes the design of an all-fibre multi-wavelength erbium doped fibre laser operating at room temperature. By using a Sagnac loop filter, multiple wavelength channels are obtained with 0.8nm spacing in the C-band and simultaneous multi-wavelength operation is achieved through an intra-cavity sinusoidal phase modulator. A polarization controller inside the filter is helpful in controlling the multi-wavelength operation. The effects of modulation frequency, modulation index and pump power on the multi-wavelength operation are experimentally investigated. The fibre laser has potential applications in fibre Bragg grating sensors and fibre optic spectroscopy.