A collinear T-cavity VECSEL system generating intracavity Hermite-Gaussian modes at multiple wavelengths, configured to vary each of these wavelengths individually and independently. A mode converter element and/or an astigmatic mode converter is/are aligned intracavity to reversibly convert the Gaussian modes to HG modes to Laguerre-Gaussian modes, the latter forming the system output having any of the wavelengths provided by the spectrum resulting from nonlinear frequency-mixing intracavity (including generation of UV, visible, mid-IR light). The laser system delivers Watt-level output power in tunable high-order transverse mode distribution.

A semiconductor laser including a waveguide having a core, a confinement layer to bury the core, and a metallization layer. The core includes an active core region. The confinement layer surrounds the core and includes a first confinement layer between the core and the semiconductor substrate below the core, a second confinement layer above the core, and a third confinement layer to either or both sides of the core. The metallization layer is located above the confinement layers and include a first metallization layer and a second metallization layer. The first metallization layer is in direct contact with the second confinement layer and the third confinement layer, while the second metallization layer is disposed above the first layer. The first metallization layer is tuned to have a plasmon resonance corresponding to a higher order mode with high loss.

A method for manufacturing a light emitting device can include providing a substrate; forming a first active layer with a first electrical polarity; forming a light emitting region configured to emit light with a target wavelength between 200 nm and 300 nm; forming a second active layer with a second electrical polarity; forming a first electrical contact layer, optionally comprising a first optical reflector; removing a portion of the first electrical contact layer, the second active layer, the light emitting region, and the first active layer to form a plurality of mesas; and forming a second electrical contact layer. Each mesa can include a mesa width smaller than 10 times the target wavelength that confines the emitted light from the light emitting region to fewer than 10 transverse modes, or a mesa width smaller than twice a current spreading length of the light emitting device.

A single-mode micro-laser based on a single whispering gallery mode optical microcavity and a preparation method thereof described includes: preparing a desired single whispering gallery mode optical microcavity doped with rare earth ions or containing a gain material such as quantum dots, wherein an optical microcavity configuration include a micro-disk cavity, a ring-shaped microcavity, and a racetrack-shaped microcavity; a material type include lithium niobate, silicon dioxide, silicon nitride, etc.; preparing an optical fiber cone or an optical waveguide of a required size which can excite high-order modes of the optical microcavity, such as a ridge waveguide and a circular waveguides; and coupling, integrating, and packaging the optical fiber cone or the optical waveguide with the microcavity. A pump light is coupled to the optical fiber cone or the optical waveguide to excite a compound mode with a polygonal configuration.

An optical device includes a first reflecting section, a second reflecting section, and a confining section. The first reflecting section is constituted of a thin-wire waveguide-type one-dimensional photonic crystal. The second reflecting section is constituted of a thin-wire waveguide-type one-dimensional photonic crystal of which a lattice constant differs from that of the first reflecting section. The confining section is sandwiched between the first reflecting section and the second reflecting section. A Fabry-Perot optical resonator is constituted by the first reflecting section, the confining section, and the second reflecting section.

A quantum-cascade laser element includes: an embedding layer including a first portion formed on a side surface of a ridge portion, and a second portion extending from an edge portion of the first portion along a width direction of a semiconductor substrate; and a metal layer formed at least on a top surface of the ridge portion and on the first portion. A surface of the first portion has a first inclined surface inclined with respect to the side surface to go away from the side surface as going away from the semiconductor substrate, and a second inclined surface located opposite to the semiconductor substrate with respect to the first inclined surface and inclined with respect to a center line to approach the center line as going away from the semiconductor substrate. The metal layer extends over the first inclined surface and the second inclined surface.

A beam combining device and method for a Bragg grating external-cavity laser module has a plurality of side by side light-emitting modules that use a Bragg grating to perform wavelength locking. Output light of the modules is incident to a beam combining element after passing through a focusing optical element for beam combining, and light subjected to beam combining is reflected partially and transmitted partially under the effect of a light splitting element. A part is incident into a dispersion element at a diffraction angle of the element. Parallel light is formed under the effect of a conversion optical element. Spots of the light beams of corresponding wavelengths of the light-emitting modules are formed on an image acquisition mechanism. Whether the wavelengths of the corresponding light-emitting modules are locked is determined by whether there is a deviation between preset spots and spots formed by the module on the acquisition mechanism.

A laser module includes a gain chip, temperature sensors, a case, and a thermoelectric cooler (TEC). The gain chip emits a laser beam. One of the temperature sensors measures a first temperature of the gain chip and is encompassed by the gain chip. The other temperature sensor is adhered to the case and measures a second temperature. The TEC tunes the laser beam emitted by the gain chip to a desired wavelength by varying the first temperature of the gain chip through a set of third temperatures for various values of the second temperature. The set of third temperatures is selected from various values of the first temperature such that the laser beam emitted at the set of third temperatures is mode-hop free.

Disclosed are a design method, a product and an application of a high-repetition-frequency and multi-wavelength ultrashort pulse mode-locked photonic integrated chip. Components for designing the mode-locked photonic integrated chip include a semiconductor optical amplifier array providing gains for N wavelength channels; a phase delay line array which includes phase delay lines with different lengths and separately compensates for different effective optical path differences of gain light of the wavelength channels caused by a dispersion effect; a flattened arrayed waveguide grating multiplexing the gain light with the effective optical path differences compensated, and multiplexing N-channel optical pulse signals into one-channel optical pulse signal; a saturable absorber forming, with the arrayed waveguide grating, N individual and synchronized different wavelength mode-locked optical pulse channels; and a semiconductor optical amplifier used for gaining and outputting an output pulse of the saturable absorber.

A quantum-cascade laser element includes: an embedding layer including a first portion formed on a side surface of a ridge portion, and a second portion extending from an edge portion of the first portion on a side of a semiconductor substrate along a width direction of the semiconductor substrate; and a metal layer formed at least on a top surface of the ridge portion and on the first portion. A surface of the second portion on a side opposite to the semiconductor substrate is located between a surface of an active layer on a side opposite to the semiconductor substrate and a surface of the active layer on a side of the semiconductor substrate. When viewed in the width direction of the semiconductor substrate, a part of the metal layer on the first portion overlaps the active layer. The metal layer is directly formed on the first portion.