Methods, systems, and apparatus, including a laser including a layer having first and second regions, the first region including a void; a mirror section provided on the layer, the mirror section including a waveguide core, at least part of the waveguide core is provided over at least a portion of the void; a first grating provided on the waveguide core; a first cladding layer provided between the layer and the waveguide core and supported by the second region of the layer; a second cladding layer provided on the waveguide core; and a heat source configured to change a temperature of at least one of the waveguide core and the grating, where an optical mode propagating in the waveguide core of the mirror section does not incur substantial loss due to interaction with portions of the mirror section above and below the waveguide core.

A broad area quantum cascade laser subject to having high order transverse optical modes during operation includes a laser cavity at least partially enclosed by walls, and a perturbation in the laser cavity extending from one or more of the walls. The perturbation may have a shape and a size sufficient to suppress high order transverse optical modes during operation of the broad area quantum cascade laser, whereby a fundamental transverse optical mode is selected over the high order transverse optical modes. As a result, the fundamental transverse mode operation in broad-area quantum cascade lasers can be regained, when it could not otherwise be without such a perturbation.

A semiconductor laser includes a substrate having a principal surface; an active region having a top surface and a side surface, the active region including a plurality of quantum well structures arranged in a direction of a first axis intersecting the principal surface of the substrate; a semiconductor mesa having first and second portions arranged in a direction of a waveguide axis above the principal surface of the substrate, the semiconductor mesa including the active region; a first semiconductor region of a first conductivity type on the top and side surfaces of the active region in the first portion of the semiconductor mesa; and a collector region on the side surface of the active region in the second portion of the semiconductor mesa.

Provided is a laser resonator for generating a laser light by absorbing energy from outside. The laser resonator includes a metal body and a gain medium layer having a ring shape. The gain medium layer of a ring shape may be provided on the metal body and may generate the laser light by a plasmonic effect.

A process of forming a semiconductor optical device is disclosed. The semiconductor optical device provides a waveguide structure accompanied with a heater for varying a temperature of the waveguide structure. The process includes steps of: (a) forming a striped mask on a semiconductor substrate; (b) selectively growing a dummy layer on the semiconductor substrate; (c) removing the patterned mask; (d) burying the dummy layer by a supplemental layer; (e) exposing a portion of the dummy layer by etching a portion of the supplemental layer; (f) and removing the dummy layer by immersing the dummy layer within a solution that shows an etching rate for the dummy layer enough faster than an etching rate for the supplemental layer and the substrate so as to leave a void in a region the dummy layer had existed.

Methods, systems, and apparatus, including a laser including a layer having first and second regions, the first region including a void; a mirror section provided on the layer, the mirror section including a waveguide core, at least part of the waveguide core is provided over at least a portion of the void; a first grating provided on the waveguide core; a first cladding layer provided between the layer and the waveguide core and supported by the second region of the layer; a second cladding layer provided on the waveguide core; and a heat source configured to change a temperature of at least one of the waveguide core and the grating, where an optical mode propagating in the waveguide core of the mirror section does not incur substantial loss due to interaction with portions of the mirror section above and below the waveguide core.

Methods, systems, and apparatus, including a laser including a layer having first and second regions, the first region including a void; a mirror section provided on the layer, the mirror section including a waveguide core, at least part of the waveguide core is provided over at least a portion of the void; a first grating provided on the waveguide core; a first cladding layer provided between the layer and the waveguide core and supported by the second region of the layer; a second cladding layer provided on the waveguide core; and a heat source configured to change a temperature of at least one of the waveguide core and the grating, where an optical mode propagating in the waveguide core of the mirror section does not incur substantial loss due to interaction with portions of the mirror section above and below the waveguide core.

Methods, systems, and apparatus, including a laser including a layer having first and second regions, the first region including a void; a mirror section provided on the layer, the mirror section including a waveguide core, at least part of the waveguide core is provided over at least a portion of the void; a first grating provided on the waveguide core; a first cladding layer provided between the layer and the waveguide core and supported by the second region of the layer; a second cladding layer provided on the waveguide core; and a heat source configured to change a temperature of at least one of the waveguide core and the grating, where an optical mode propagating in the waveguide core of the mirror section does not incur substantial loss due to interaction with portions of the mirror section above and below the waveguide core.

An optical device includes a laser or amplifier positioned on a base. The laser includes a ridge of a gain medium positioned on the base such that the base extends out from under the ridge. The ridge includes a top that connects lateral sides of the ridge. Electronics are configured to drive an electrical current through the ridge such that the electrical current passes through one or more of the lateral sides of the ridge.

III-V lasers integrated with silicon photonic circuits and methods for making the same include a three-layer semiconductor stack formed from III-V semiconductors on a substrate, where a middle layer has a lower bandgap than a top layer and a bottom layer; a mirror region monolithically formed at a first end of the stack, configured to reflect emitted light in the direction of the stack; and a waveguide region monolithically formed at a second end of the stack, configured to transmit emitted light.