Multiwavelength fiber ring lasers

Abstract

The main objective of this project is to build a multi-wavelength ring laser operated at room temperature. Multi-wavelength fiber laser sources have potential applications in optical communication systems and optical fiber sensing networks. The literature related to the fiber lasers is generally reviewed in order to understand the principle and the current development of the fiber lasers. Essential optical components used in the multi-wavelength ring laser are discussed. They play important roles in the laser cavity. A Mach-Zehnder interferometer is used as the comb filter and its theoretical model is presented. By the use of an optical switch, the operating wavelengths can be shifted between two wavelength bands, centered at 1555 nm and 1565 nm respectively. Simultaneous operation of 10 wavelengths with wavelength spacing of 0.5 nm and SNR of 25 dB is demonstrated in an Erbium doped fiber ring laser having such a comb filter at 77 K. The theoretical analysis and experimental investigation for the hybrid gain medium, which combines a homogeneous gain medium and an inhomogeneous gain medium, are carried out. Linearization, Perturbation Analysis and Stability Analysis are employed to obtain a theoretical model of the ring laser with the hybrid gain medium. A stable 22 wavelengths output from a hybrid gain laser with wavelength spacing of 0.5 nm and SNR of 25 dB is observed experimentally at room temperature.