Evanescent-Wave Pumped and Gain Coupled Whispering-Gallery-Mode Fibre Laser

Abstract

A novel Whispering–Gallery–Mode (WGM) fibre laser is demonstrated by pumping and gain coupling with evanescent-waves in this chapter. The properties of the fibre laser, including energy threshold, produced length and polarization of lasing emission have been investigated. Two important applications of the fibre lasers on optoelectronics, linearly polarized three-color lasing emission and single WGM lasing emission, are also demonstrated in this chapter. The chapter is composed by four parts. In part one, an evanescent wave pumped and gain coupled micro-cavity fiber laser is demonstrated by inserting a bare fused quartz fiber into a glass capillary filled with Rhodamine 6G dye solution, and its energy threshold properties, including the energy threshold varied with the refractive index of the dye solution for different fiber diameters and the produced length of lasing emission, are then investigated. In part two, the polarization properties of an evanescent-wave pumped WGM fibre laser are investigated. It is found that there are two kinds of polarization lasing beam emitting from the evanescent-wave pumped WGM fibre laser under two different pump conditions. In part three, WGM fibre laser, emitting linearly polarized three-color light, is demonstrated by pumping and gain coupling with evanescent waves. In part four, a coupled cylinder-cavity structure, which is used to increase the free spectral range of a WGM fiber laser, is demonstrated by binding two bare optical fibres together, and single WGM lasing emission is realized.