A laser device includes: a plurality of laser diodes that emit laser beams having different wavelengths; a partial reflection mirror that resonates the plurality of laser beams emitted by the plurality of laser diodes; and a wavelength dispersion element that causes the plurality of laser beams incident from the plurality of laser diodes in different orientations of optical axes of the laser beams to travel to the mirror with the optical axes aligned. Each of the plurality of laser diodes is integrally formed with an adjustment component that is rotatable around an emission end of the laser diode.

A continuous optical beat laser element for generating terahertz (THz) waves and a laser source using same includes periodically poled lithium niobate (ppLN) crystals arranged along a predetermined direction forming a surface generally parallel to the predetermined direction. A Ti diffused region is applied on the surface and an array of gold nanowires are applied on the Ti diffused region to form a gold metal-insulator-metal (MIM) element that optimizes coupling and channeling of THz radiation from the crystals into the gold nanowires. The system provides a simple, stable, compact and cost-effective THz source using a widely tunable C-band SOA-based laser to excite a non-linear photo-mixer to produce terahertz radiation that ranges from 0.8 to 2.51 THz at room temperature. This laser source can be modified into an all fiber-based THz generator by embedding ppLN crystals in a fiber filament configuration resulting in less absorption and producing high output power.

An external resonator-type semiconductor laser device 1A includes an external resonator formed of one or a plurality of laser diode light sources and a VBG; an optical fiber which outputs output light La from the laser diode light source toward the VBG, and into which return light Lb from the VBG is input; and a displacement unit that displaces a disposition position of the VBG with respect to an input and output end surface of the optical fiber.

Examples of the present disclosure include a tunable laser comprising a waveguide including gain section. The waveguide overlies and is optically coupled to another waveguide. The another waveguide has a reflector at one end. A laser cavity is formed in the waveguides.

A QCL may include a substrate, and a semiconductor layer adjacent the substrate. The semiconductor layer may define branch active regions, and a stem region coupled to output ends of the branch active regions. Each branch active region may have a number of stages less than 30.

A multi-channel laser source, including: a bus waveguide coupled, at an output end of the bus waveguide, to an output of the multi-channel laser source; a first semiconductor optical amplifier; a first back mirror; a first wavelength-dependent coupler, having a first resonant wavelength, on the bus waveguide; a second semiconductor optical amplifier; a second back mirror; and a second wavelength-dependent coupler, on the bus waveguide, having a second resonant wavelength, different from the first resonant wavelength. In some embodiments the first semiconductor optical amplifier is coupled to the bus waveguide by the first wavelength-dependent coupler, which is nearer to the output end of the bus waveguide than the second wavelength-dependent coupler, the second semiconductor optical amplifier is coupled to the bus waveguide by the second wavelength-dependent coupler, and the first wavelength-dependent coupler is configured to transmit light, at the second resonant wavelength, along the bus waveguide.

A laser device is provided which comprises a common waveguide layer and a plurality of laser bodies, wherein each of the laser bodies has an active region configured for generating coherent electromagnetic radiation. The laser bodies are arranged side by side on the common waveguide layer, wherein the laser bodies are directly adjacent to the common waveguide layer. In particular, the laser bodies are configured to be phase-coupled to each other via the waveguide layer during operation of the laser device.

Furthermore, a method for producing such a phase-coupled laser device is provided.

Apparatus, systems and methods to spectrally beam combine a group of diode lasers in an external cavity arrangement. A dichroic beam combiner or volume Bragg grating beam combiner is placed in an external cavity to force each of the diode lasers or groups of diode lasers to oscillate at a wavelength determined by the passband of the beam combiner. In embodiments the combination of a large number of laser diodes in a sufficiently narrow bandwidth to produce a high brightness laser source that has many applications including as to pump a Raman laser or Raman amplifier.

Low phase noise signal generated in a small structure is required for communication and high-resolution imaging. A DBR based multi-mode laser is combined with mode-locking method to build frequency stabilized and tunable RF signal generator. The number of the output modes from each laser is adjusted using reflecting bandwidth of distributed Bragg reflector and electro-absorption (EA) modulator for amplitude control, while the phase section in integrated laser system provides frequency tuning. Mode-locking of 60 laser modes results in a highly frequency stable 10 GHz RF beat-notes with a calculated phase noise of −150 dBc/Hz at 10 kHz offset frequency.

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.