An acousto-optic modulator (AOM) laser frequency shifter system includes a laser configured to generate an incident beam, a first optical splitter optically coupled to the laser and configured to split the incident beam into at least one portion of the incident beam, at least one phase-shift channel optically coupled to the first optical splitter and configured to generate at least one frequency-shifted beam with an acousto-optic modulator (AOM) from the at least one portion of the incident beam received from the first optical splitter, and a second optical splitter configured to receive the at least one frequency-shifted beam from the at least one phase-shift channel and configured to direct the at least one frequency-shifted beam to an interferometer configured to acquire an interferogram of a sample with the at least one frequency-shifted beam.

A disclosed semiconductor laser device includes a distributed feedback portion serving as a light-emittable active region the distributed feedback portion having a diffraction grating; and a distributed reflective portion serving as a passive reflective mirror, the distributed reflective portion having a diffraction grating, wherein the distributed feedback portion includes a first region adjacent to the distributed reflective portion and having a diffraction grating having a predetermined standard period, a phase shift region adjacent to the first region, the phase shift region being longer by twice or more than the standard period, and a second region adjacent to an opposite side to the first region of the phase shift region and having a diffraction grating with the standard period, and the phase shift region optically changes a phase of laser beam between the first region and the second region.

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.

There is disclosed in one example a communication system, including: a data transmission interface; and a wavelength division multiplexing (WDM) silicon laser source to provide modulated data on a carrier laser via the data transmission interface, the WDM laser including a single laser cavity to generate an internally multiplexed multi-wavelength laser, the single laser cavity including a filter having a first grating period to generate a first wavelength and a second grating period to generate a second wavelength, the second grating period superimposed on the first grating period.

Single-mode quantum cascade semiconductor lasers are provided. The lasers comprise a laser element, the laser element comprising a quantum cascade active layer; an upper cladding layer over the quantum cascade active layer; and a lower cladding layer under the quantum cascade active layer, wherein the quantum cascade active layer, the upper cladding layer and the lower cladding layer define a guided optical mode. The quantum cascade active layer and the upper and lower cladding layers are shaped in the form of a ridge structure having a front face, a back face opposite the front face, and a lasing face through which laser emission exits the ridge structure, the ridge structure configured such that the laser emission has a single-lobe, far-field beam pattern from the ridge structure comprising certain sections, including tapered sections, collateral sections, or both.

A distributed feedback plus reflection (DFB+R) laser includes an active section, a passive section, a low reflection (LR) mirror, and an etalon. The active section includes a distributed feedback (DFB) grating and is configured to operate in a lasing mode. The passive section is coupled end to end with the active section. The LR mirror is formed on or in the passive section. The etalon includes a portion of the DFB grating, the passive section, and the LR mirror. The lasing mode of the active section is aligned to a long-wavelength edge of a reflection peak of the etalon.

A tunable laser that includes an array of parallel optical amplifiers is described. The laser may also include an intracavity NM coupler that couples power between a cavity mirror and the array of parallel optical amplifiers. Phase adjusters in optical paths between the NM coupler and the optical amplifiers can be used to adjust an amount of power output from M1 ports of the NM coupler. A tunable wavelength filter is incorporated in the laser cavity to select a lasing wavelength.

A Distributed Feedback Laser comprises a layer stack comprising a p-layer, an n-layer which are arranged so as to form an pn-junction having an active layer in between. Within the layer stack, an index coupled grating layer or a grating layer is arranged which comprises a first, a second, and a third grating portion. The first, the second, and the third grating portions are asymmetrically arranged along a lateral dimension of the layer stack, wherein the second grating portion is formed without a grating structure.

Conventional integrated optical amplifiers, which combine different types of platforms, e.g. silicon photonic integrated circuit for the device layer, and a Group III-V material for the gain medium, typically include a curved waveguide extending through the gain medium coupled to waveguides in the main device layer. Unfortunately, the radius of curvature of the curved waveguide becomes a limiting factor for both size and amplification. Accordingly, an optical amplifier which eliminates the need for the curved waveguide by including a coupler for splitting an input optical signal into two sub-beams, for passage through the gain medium, and a reflector, such as a U-turn, for reflecting or redirecting the two sub-beams back through the gain medium to the coupler for recombination, would be a welcome improvement. A phase tuner may also be provided to ensure coherence cancellation between the two sub-beams to maximize output and minimize back reflection without requiring an isolator.

A light emitting device, an optical module and a manufacturing method thereof are disclosed. According to an example of the disclosure, the light emitting device may comprise an optical waveguide chip, a light emitting chip and a grating between the light emitting chip and the optical waveguide chip. The light emitting chip may emit laser light. The grating may couple the laser light emitted from the active layer into the optical waveguide chip in a way that the laser light is output along a length direction of the optical waveguide chip.