A photonics frequency comb generator includes two integrated dies: an indium phosphide die laser of a first wavelength is grown on from, and a silicon photonics die having a microring resonator connected to the laser and frequency modulators. The microring resonator converts the first wavelength into a number of second wavelengths. One type of the microring resonator is a hybrid non-linear optical wavelength generator, comprising non-silicon materials, such as SiC or SiGe built on silicon to yield a non-linear wavelength generation. The second wavelengths are generated by adjusting the ring's geometric size and a distance between the ring and the traverse waveguide. Another type of microring resonator splits the first wavelength into a plurality of second wavelengths and transmits the multiple second wavelengths to filters and modulators, and each selects and modulates one of the second wavelengths in a one-to-one relationship. This frequency comb generator has applications in WDM/CWDM and multi-chip modules in high speed transceivers.

A semiconductor light source including a planar optical component that focuses long-wavelength (e.g., infrared) light emitted in a resonant cavity into a nonlinear crystal, which then converts the long-wavelength light into light having a shorter wavelength (e.g., visible light) by frequency doubling. A wavelength-selective reflection layer on the nonlinear crystal reflects the long-wavelength light back into the resonant cavity to form an external cavity and transmits the light having the shorter wavelength out of the external cavity. The resonant cavity includes an active region that emits the long-wavelength light at a high efficiency. The planar optical component includes a micro-lens formed in semiconductor layers or a gradient refractive index lens formed in the nonlinear crystal.

A system for resonantly enhanced frequency conversion includes a nonlinear crystal for frequency converting a pump laser beam, and mirrors forming a ring resonator for the pump laser beam such that a closed propagation path of the pump laser beam, inside the ring resonator, passes through the nonlinear crystal. The mirrors include an adaptive mirror, a curved-mirror pair positioned in a first segment of the propagation path spanning between the adaptive mirror and the nonlinear crystal, and an input coupler for coupling the pump laser beam into the ring resonator. The curved-mirror pair forms an imaging system having conjugate planes at the adaptive mirror and the nonlinear crystal. The input coupler is positioned in a second segment of the propagation path that spans between the adaptive mirror and the nonlinear crystal and does not include deflection by the curved-mirror pair.

A visible light source includes a substrate, a first reflector and a second reflector configured to reflect infrared light and arranged vertically to form a vertical cavity on the substrate, an active region in the vertical cavity and configured to emit infrared light, a micro-resonator on the substrate and configured to receive the infrared light emitted by the active region and generate visible light through optical parametric oscillation, and an output coupler configured to couple the visible light generated in the micro-resonator out of the micro-resonator.

A QCL includes a semiconductor substrate and an active layer provided on the semiconductor substrate. The active layer has a cascade structure in which a unit laminate including a light emission layer which generates light and an injection layer to which electrons are transported from the light emission layer is laminated in multiple stages. The light emission layer and the injection layer each have a quantum well structure in which quantum well layers and barrier layers are alternately laminated. A separation layer including a separation quantum well layer having a layer thickness smaller than an average layer thickness of the quantum well layers included in the light emission layer and smaller than an average layer thickness of the quantum well layers included in the injection layer is provided between the light emission layer and the injection layer in the unit laminate.

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 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.

Systems and methods are provided for optimizing the energy output of a laser system, such as a Light Detection and Ranging (LIDAR) system, by allowing the laser system to be tuned while the laser is in operation. For example, in an embodiment, a sensor, such as a photoresistor, is used to perform a scan to determine whether turning the crystal will result in increased energy. Crystal turners, such as servo motors, can be used to turn the crystal until the energy stops increasing.

The invention relates to a method for modulating the resonant frequency of an optical resonator (1) in accordance with a periodic, not necessarily harmonic, modulation signal (U.sub.mod(t)). Fast modulation of an optical resonator is intended to be made possible in which the current resonant frequency follows the modulation signal (U.sub.mod(t)) as precisely as possible, and specifically at a fundamental frequency of the modulation signal in the kHz range. To do this, the invention proposes the following method steps: deriving an error signal (E(t)) from a light field circulating in the resonator (1), wherein the error signal (E(t)) indicates the deviation of the optical frequency of the light field from a target value, deriving a first actuating signal (S.sub.1(t)) from the error signal (E(t)) by means of a controller (6), generating a second actuating signal (S.sub.2(t)), which has actuating-signal components at one or more harmonics (f.sub.mod, 2f.sub.mod, . . . ) of the fundamental frequency (f.sub.mod) of the modulation signal (U.sub.mod(t)), and applying a superposition signal made up of the first and the second actuating signal (S.sub.1(t), S.sub.2(t)) to an actuator (3) that changes the optical path length of the resonator (1). In other words, the invention makes use of a combination of control and narrow-band feed-forward control tuned to the spectrum of the modulation signal (U.sub.mod(t)) and of the error signal (E(t)) to modulate the resonant frequency. Preferably, the feed-forward control used for generating the second actuating signal (S.sub.2(t)) is automatically adapted in accordance with the error signal (E(t)). In addition, the invention relates to an accordingly configured optical system.

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.