Mid-IR microchip laser: ZnS:Cr2+ laser with saturable absorber material

A laser transmitter comprising:

• a pump radiation source configured to generate radiations in spatially separate channels;
• a substrate, integrated on an optical chip, comprising a fiber connection to receive pumped radiations from the pump radiation source, the substrate further comprising etchings to couple the spatially separate channels of the pumped radiation to respective spatially separated channels on the substrate and multiple waveguides to deliver the radiation in the spatially separate channels to an active gain medium;
• the active gain medium, integrated as part of the substrate, comprising the multiple waveguides and having broad amplification spectra to emit amplified radiations of the spatially separate channels, each channel representing a corresponding wavelength, the active gain medium including a tapered grating structure formed across the multiple waveguides such that a spacing between periodic components of the grating structure gradually increases between a first waveguide and a last waveguide of the multiple waveguides to provide an autocollimation regime of retroreflection for multifrequency oscillation of the pumped radiation that enters the active region, the active gain medium comprising II-VI material;
• and
• one of an acousto-optic modulator or an electro-optic modulator integrated as part of the active gain medium within a cavity of the laser transmitter.