A compact, wavelength-stabilized laser source is provided by utilizing a specialty gain element (i.e., formed to include a curved waveguide topology), where a separate wavelength stabilization component (for example, a fiber Bragg grating (FBG)) is used one of the mirrors for the laser cavity. That is, the FBG takes the place of the physical “front facet” of the gain element, and functions to define the laser cavity in the first instance, while also utilizing the grating structure to impart the desired wavelength stability to the output from the packaged laser source. As a result, the FBG is disposed within the same package used to house the gain element and provides a wavelength-stabilized laser source in a compact form.

The optical module includes: a housing having first and second end walls and a pair of side walls; a semiconductor laser element; a first TEC; a wavelength locker unit including an optical splitting component and an etalon filter; and a second TEC. The second end wall is provided with a feedthrough. The pair of side walls is not provided with an external connection terminal. The second TEC is disposed between the first TEC and the second end wall and has: a first substrate thermally coupled to a bottom surface of the housing; a second substrate thermally coupled to the etalon filter; and a heat transfer part that transfers heat. The optical module further includes a wiring pattern that is arranged side by side with the heat transfer part and that supplies electric power to the first TEC from the feedthrough.

The invention relates to a photonic component (1) having at least one semiconductor laser amplifier (200), which has at least one first mirror surface (210a) for coupling and/or decoupling optical radiation (S). The first mirror surface (210a) of the semiconductor laser amplifier (200) is coupled to a photonically integrated chip (100), wherein the chip (100) is arranged such that the chip can emit optical radiation (S) from the chip top side (O100) thereof in the direction of the first mirror surface (210a) and couple said radiation in the semiconductor laser amplifier (200), and wherein the emitting of the radiation (S) away from the chip top side (O100) occurs in the direction of the first mirror surface (210a) at an angle of 90°±20°, in particular perpendicular, to the chip top side (O100).

A semiconductor-laser-device assembly includes a mode-locked semiconductor-laser-element assembly including a mode-locked semiconductor laser element, and a dispersion compensation optical system, on which laser light emitted from the mode-locked semiconductor laser element is incident and from which the laser light is emitted; and a semiconductor optical amplifier having a layered structure body including a group III-V nitride-based semiconductor layer, the semiconductor optical amplifier configured to amplify the laser light emitted from the mode-locked semiconductor-laser-element assembly.

Provided is an optical semiconductor element including: a stacked structure body 20 formed of a first compound semiconductor layer 21, a third compound semiconductor layer (active layer) 23, and a second compound semiconductor layer 22. A fundamental mode waveguide region 40 with a waveguide width W.sub.1, a free propagation region 50 with a width larger than W.sub.1, and a light emitting region 60 having a tapered shape (flared shape) with a width increasing toward a light emitting end surface 25 are arranged in sequence.

Techniques for efficient alignment of a semiconductor laser in a Photonic Integrated Circuit (PIC) are disclosed. In some embodiments, a photonic integrated circuit (PIC) may include a semiconductor laser that includes a laser mating surface, and a substrate that includes a substrate mating surface. A shape of the laser mating surface and a shape of the substrate mating surface may be configured to align the semiconductor laser with the substrate in three dimensions.

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 terahertz quantum cascade laser device is provided comprising a substrate having a top substrate surface, a bottom substrate surface, and an exit facet extending between the top substrate surface and the bottom substrate surface at an angle θ.sub.tap. The device comprises a waveguide structure having a top surface, a bottom surface, a front facet extending between the top surface and the bottom surface and positioned proximate to the exit facet, and a back facet extending between the top surface and the bottom surface and oppositely facing the front facet. The waveguide structure comprises a quantum cascade laser structure configured to generate light comprising light of a first frequency ω.sub.1, light of a second frequency ω.sub.2, and light of a third frequency ω.sub.THz, wherein ω.sub.THz=ω.sub.1−ω.sub.2; an upper cladding layer; and a lower cladding layer. The device comprises a distributed feedback grating layer configured to provide optical feedback for one or both of the light of the first frequency ω.sub.1 and the light of the second frequency ω.sub.2 and to produce lasing at one or both of the first frequency ω.sub.1 and the second frequency ω.sub.2, thereby resulting in laser emission at the third frequency ω.sub.THz at a Cherenkov angle θ.sub.THz through the bottom surface of the waveguide structure into the substrate and exiting the substrate through the exit facet. The device comprises a high-reflectivity coating on the front facet of the waveguide structure.

Disclosed is a semiconductor laser device assembly including a semiconductor laser device; and a dispersion compensation optical system, where a laser light exited from the semiconductor laser device is incident and exits to control a group velocity dispersion value of the laser light exited from the semiconductor laser device per wavelength.

A method of calibrating a tunable laser includes shifting a filter output peak defined by a tunable optical feedback filter of the tunable laser in an optical spectral domain to align with a target etalon output peak of a plurality of spaced etalon output peaks defined by an etalon of the tunable laser. The method also includes shifting a cavity frequency grid defined by cavity modes of the tunable laser to align a target cavity mode of the cavity frequency grid with the filter output peak and shifting the spaced output peaks defined by the etalon to align a target etalon output peak with a target wavelength of an output wavelength grid. The method includes modifying a bias current and a modulation current of a gain section of the tunable laser to achieve a defined output modulation amplitude and a defined extinction ratio.