A Bragg grating includes a lower waveguide layer, a middle waveguide layer disposed on the lower waveguide layer, an upper waveguide structure disposed on the middle waveguide layer opposite to the lower waveguide layer, and a buried layer. The upper waveguide structure includes upper waveguide elements that are arranged on a surface of the middle waveguide layer, and that are spaced apart from one another by cavities. The buried layer fills the cavity. The middle waveguide layer has a refractive index lower than that of each of the lower waveguide layer and the upper waveguide elements. The lower waveguide layer has a doping type the same as that of the middle waveguide layer. A method for manufacturing the Bragg grating is also provided.

A plasmonic laser array device may comprise a first microcavity element having a first radiating end facet and a second radiating end facet opposite the first radiating end facet in a longitudinal direction of the device. The device may comprise a second microcavity element having a third radiating end facet and a fourth radiating end facet opposite the third radiating facet in the longitudinal direction. The device may comprise a first microcavity gap configured to separate the first microcavity element and the second microcavity element in the longitudinal direction. The device may comprise a bottom (e.g., metal) layer configured to underly the first microcavity element, the second microcavity element, and the first microcavity gap. The device may comprise an arrangement that places the first microcavity element and the second microcavity element into a phase-locked orientation for a phased-locked operation of the plasmonic laser array device.

There is provided a method of operating a laser. The method comprises receiving a target power and calculating an operating power of a lasing module of the laser. The operating power may be calculated based on the target power and a minimum lasing power of the lasing module. The method also comprises determining an operating current for the lasing module based on the operating power, and driving the lasing module at the operating current to produce an output light having the operating power. In addition, the method comprises providing the output light to an optical modulator of the laser, and operating the optical modulator to modulate the output light to have an output power corresponding to the target power.

Various semiconductor laser and optical amplifier designs and injection current control methods are disclosed that enable tailoring a distribution of the injection current along an active waveguide of the laser or the optical amplifier. Such configurations can be used to reduce longitudinal current crowding along the active waveguide of the laser or the optical amplifier. The electrodes and/or one or more layers of the laser or the optical amplifier may be segmented to provide a tailored longitudinal injection current distribution.

The laser assembly includes a semiconductor with an active semiconductor region, a controllable oscillator for generating a periodic electric signal that is applied to the semiconductor laser to generate a surface acoustic wave in or near the active semiconductor region such that a diffraction grating structure is created in or near the active semiconductor region by the surface acoustic wave, an emission wavelength of the active semiconductor region being determined by a periodicity of the diffraction grating structure, wherein the controllable oscillator is configured to set a frequency of the periodic electric signal in accordance with a control signal, and a control circuit for generating the control signal for the controllable oscillator in such a manner that a shift of the emission wavelength from heating of the active semiconductor region during emission of the optical signal is at least partially compensated by an opposite shift of the emission wavelength from a change of the periodicity of the diffraction grating structure in or near the active semiconductor region.

A quantum dot comb laser, is provided that comprises a first waveguide having a first width; and a second waveguide running above the first waveguide that includes: a quantum dot layer; a first region of a second width less than the first width; a second region connected to the first region and comprising a reflective grating; and a third region connected at a first end to the second region and at a second end to an output surface wherein the third region tapers from the second width at the first end to a third width, less than the second width, at the second end.

A tunable laser has a first mirror, a second mirror, a gain medium, and a directional coupler. The first mirror and the second mirror form an optical resonator. The gain medium and the directional coupler are, at least partially, in an optical path of the optical resonator. The first mirror and the second mirror comprise binary super gratings. Both the first mirror and the second mirror have high reflectivity. The directional coupler provides an output coupler for the tunable laser.

A tunable wavelength laser comprising a laser cavity formed by a broadband mirror and a comb mirror. The laser cavity comprising a gain region. The laser cavity is configured such that a non-integer number of cavity modes of the laser cavity are between two consecutive reflection peaks of the comb mirror.

Disclosed is an electrically driven organic semiconductor laser diode comprising a pair of electrodes, an optical resonator structure having a distributed feedback (DFB) structure, and one or more organic layers including a light amplification layer composed of an organic semiconductor, in which the distributed feedback structure is composed of a first-order Bragg scattering region, a two-dimensional distributed feedback, or a circular distributed feedback.

A method of forming a laser involves forming, on a substrate, a first epitaxial part of the laser that includes at least an active region layer surrounded by first and second waveguide layers. A dielectric layer is formed over the first epitaxial part. Two or more mask openings are patterned within the dielectric layer. The mask openings extend normal to a light-propagation direction of the laser and are spaced apart in the light-propagation direction of the laser. A second epitaxial part of the laser is formed in the mask openings using selective area epitaxy. The second epitaxial part includes a refractive grating with three-dimensional grating features.