Mode-locked fiber laser based on narrowband optical spectral filtering and amplifier similaritons

摘要

Implementations and examples of mode-locked fiber lasers based on fiber laser cavity designs that produce self-similar pulses (“similaritons”) with parabolic pulse profiles with respect to time at the output of the fiber gain media to effectuate the desired mode locking operation. An intra-cavity narrowband optical spectral filter is included in such fiber lasers to ensure the proper similariton conditions.

主权项

1. A laser device based on mode locking, comprising a laser cavity that produces laser light in form of laser pulses, wherein the laser cavity includes:
a fiber amplifier having a gain fiber section that exhibits an optical gain with a gain spectral bandwidth and operates to amplify laser pulses within the gain spectral bandwidth and to cause each laser pulse to increase a pulse duration and a pulse spectral width from entry of the gain fiber section to exit of the gain fiber section; a saturable absorber coupled to receive output light from the fiber amplifier and operable to exhibit saturable absorption of light with the light intensity and to reduce the pulse duration and the pulse spectral width of each laser pulse; and an optical spectral filter coupled to receive light from the saturable absorber and to further reduce the pulse duration and the pulse spectral width of each laser pulse, the optical spectral filter selectively transmitting light in a single narrowband while rejecting light outside the narrowband and configured to have a bandwidth for the narrowband that is sufficiently narrow to cause each laser pulse to be self similar after propagating through the fiber amplifier and to evolve into a parabolic pulse profile with respect to time at the exit of the fiber amplifier to effectuate mode locking that generates the laser pulses.