A laser system for generating a narrow linewidth semiconductor light beam includes a substrate, a gain chip affixed on the substrate and configured to amplify light beam, and an optical feedback photonic chip affixed on the substrate, optically coupled to the gain chip, and configured to output light beam, which has a narrow linewidth around a resonant frequency of the optical feedback photonic chip, to the gain chip.

A narrow linewidth mid infrared laser, including a pumping laser diode with a fast-axis compressor and a pumping wavelength λ.sub.o; and an optical resonator arranged to receive the pumping wavelength λ.sub.o, the optical resonator including a laser crystal with a lasing wavelength λ.sub.p, a dichroic mirror, and a nonlinear crystal to generate an idler wavelength λ.sub.i.

Described are various configurations of integrated wavelength lockers including asymmetric Mach-Zehnder interferometers (AMZIs) and associated detectors. Various embodiments provide improved wavelength-locking accuracy by using an active tuning element in the AMZI to achieve an operational position with high locking sensitivity, a coherent receiver to reduce the frequency-dependence of the locking sensitivity, and/or a temperature sensor and/or strain gauge to computationally correct for the effect of temperature or strain changes.

The present invention describes a laser system for eliminating astigmatism to produce an elliptical laser beam that has an ellipticity between about 0.9 to 1.0. The laser system described herein allows for increased conversion efficiency and output powers. on-linear optical elements in the laser system eliminate astigmatism. The laser system comprises one or more cavities with wavelength splitters that act as dual-minor chambers for single-pass light transmission through the non-linear optical elements to reduce cavity size or as beam splitters for double-pass light transmission through the non-linear optical elements to increase laser output power. The laser system may also include a birefringent filter and/or etalon in the first cavity for polarization and wavelength tuning. The laser system may also generate a high-power, deep-ultraviolet laser output. The laser system may also be devoid of curved mirrors and non-normal incidence reflection to eliminate astigmatism.

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.

A light emitting device includes: a light emitting element; and a wavelength conversion member including: a wavelength conversion part configured to convert light emitted from the light emitting element into light having a different wavelength and to output the light having the different wavelength, an enclosing part enclosing the wavelength conversion part, and a conducting layer disposed on the enclosing part and surrounding the wavelength conversion part. The conducting layer comprises ruthenium oxide.

An optical device includes a first reflector; a second reflector; an elastic support unit supporting the second reflector; a piezoelectric element on the elastic support unit; a light emitter configured to emit light having an oscillation wavelength; and circuitry configured to output a signal to apply drive voltage to the piezoelectric element to elastically deform the elastic support unit. The deformation of the elastic support unit changes a distance between the first reflector and the second reflector to change the oscillation wavelength of the light emitted from the light emitter.

Disclosed is a single-photon source emitting light with controllable circular polarization direction. A pillar structure above a semiconductor substrate includes a semiconductor single-quantum-dot structure. A spin injection layer is arranged above the pillar structure. A pulsed voltage is applied between the spin injection layer and the semiconductor substrate to inject a spin-polarized single-carrier from the spin injection layer into the semiconductor single-quantum-dot structure. In response to the injected single-carrier, a single-quantum-dot emits a single-photon with a circular polarization direction corresponding to the spin direction of the injected single-carrier. The polarization controllable single-photon source allows to use magnetic or electrical means to modulate the circular polarization direction of single-photon. The modulation speed by electrical mean can reach up to GHz range.

Methods for driving a tunable laser with integrated tuning elements are disclosed. The methods can include modulating the tuning current and laser injection current such that the laser emission wavelength and output power are independently controllable. In some examples, the tuning current and laser injection current are modulated simultaneously and a wider tuning range can result. In some examples, one or both of these currents is sinusoidally modulated. In some examples, a constant output power can be achieved while tuning the emission wavelength. In some examples, the output power and tuning can follow a linear relationship. In some examples, injection current and tuning element drive waveforms necessary to achieve targeted output power and tuning waveforms can be achieved through optimization based on goodness of fit values between the targeted and actual output power and tuning waveforms.

An external cavity diode laser has been developed to achieve a linear frequency chirp over a broad bandwidth using a silicon photonic filter chip as the external cavity. By appropriately chirping the cavity phase using the gain chip and/or a cavity phase modulator on the silicon photonic chip along with simultaneously varying the filter resonance, approximately linear frequency chirping can be accomplished for at least 50 GHz, although desirable structures with useful lesser chirp bandwidths are also described. With careful control of the chip design, it is possible to achieve predictable behavior of mode jumps along with large scannable ranges within a mode, which allows for stitching together segments of linear chirp through a mode jump to provide for very large chirp bandwidths greater than 1 THz.