Resonant pumped short cavity fiber laser with multiple optical resonators

Abstract

A fiber laser or fiber amplifier uses resonant pumping of the gain medium by providing a pump resonator that establishes a resonator cavity at the pump wavelength which includes the pumped gain medium. The pump resonator may be of a distributed feedback (DFB) or a distributed Bragg reflector (DBR) type construction, and may be combined with signal reflection apparatus of either DFB or DBR type construction that provides oscillation of the desired laser output wavelength. If used without a signal reflection apparatus, the invention may be operated as a resonant pumped fiber amplifier. Multiple resonators may also be pumped by a single pump source by locating each in a different branch of a multiple branch directional coupler. If the resonators are constructed to couple their outputs away from the coupler, a plurality of different laser outputs each having a different wavelength and equal output powers is provided. If the resonators couple their outputs toward the coupler, a plurality of discrete wavelengths each at the same power may be coupled onto a single waveguide. The pumping of the resonators may be from a single source the output of which is coupled into the single waveguide toward the directional coupler using a wavelength selective optical coupler that prevents optical energy outside the wavelength range of the pumping energy from reaching the pumping source.