An optical parametric device (OPD), which is selected from an optical parametric oscillator (OPO) or optical parametric generator (OPG), is configured with a nonlinear optical element (NOE) which converts an incoupled pump radiation at first frequency into output signal and idler radiations at one second frequency or different second frequencies, which is/are lower than the first frequency, by utilizing nonlinear interaction via a random quasi-phase matching process (RQPM-NOE). The NOE is made from a nonlinear optical material selected from optical ceramics, polycrystals, micro and nanocrystals, colloids of micro and nanocrystals, and composites of micro and nanocrystals in polymer or glassy matrices. The nonlinear optical material is prepared by modifying a microstructure of the initial sample of the NOE such that an average grain size is of the order of a coherence length of the three-wave interaction which enables the highest parametric gain achievable via the RQPM process.

A semiconductor laser and a photonic nonlinear circuit chip are integrated together. The nonlinear circuit chip may include a nonlinear waveguide configured or controlled to enable sum-frequency generation, difference-frequency generation, second-harmonic generation, parametric amplification, or other nonlinear processes. Coupling between the semiconductor laser and the nonlinear circuit may be optimized by mode-matching, while back-reflections are minimized by diverting the reflections so that optical isolators are not needed. The integration of the semiconductor laser and the nonlinear photonic circuit chip enables nonlinear optical processing using a compact and scalable platform in a flexible manner that is compatible with different types of semiconductor lasers and different operation regimes. An additional input is provided so users can input an optical signal into the photonic chip for processing therein. In some examples, the photonic chip is configured with pump resonators, such as racetrack resonators. Method and device examples are described herein.

The invention provides a frequency comb laser device comprising a laser cavity having an optical gain material for coupling light to a waveguide comprising a dispersive material; a reflector at the end of the optical gain material and a resonant mirror at the other; where the resonant mirror comprises an on-chip waveguide coupled to a fabry perot cavity formed by one or more photonic crystal reflectors, such that lasing operation is sustained with the laser cavity. The invention makes it possible to improve the control of the dispersion of a frequency comb source through the use of a PhC structure of the present invention in combination with or without other dispersion control mechanisms.

In a signal regeneration device in which recovery of a signal quality which has been degraded during transmission in optical communication and extension of a transmission distance are achieved, the most representative method of quantizing an optical phase is a phase sensitive amplifier (PSA) and a technique that utilizes an optical parametric process through use of a highly nonlinear optical medium, but there is a demand for a technique of quantizing an optical phase which is not accompanied with an optical parametric gain, has small-sized elements, is easily integrated, and does not require high power pump light. By a technique of a hybrid optical phase squeezer (HOPS), when a phase of input light is quantized to M levels (M>2), phase conjugate light of the input light and (M1)th phase harmonic light of the input light are subjected to power modulation to be coherently added, so that quantization of the optical phase is performed through use of a simple four-wave mixing (FWM) that is not accompanied with the optical parametric gain and a general optical amplifier by using a general nonlinear optical medium such as silicon, and accordingly, a GER of equal to or higher than 30 dB can be obtained, even if a nonlinear optical element having a low nonlinearity is used.

An optical parametric device (OPD), which is selected from an optical parametric oscillator (OPO) or optical parametric generator (OPG), is configured with a nonlinear optical element (NOE) which converts an incoupled pump radiation at first frequency into output signal and idler radiations at one second frequency or different second frequencies, which is/are lower than the first frequency, by utilizing nonlinear interaction via a random quasi-phase matching process (RQPM-NOE). The NOE is made from a nonlinear optical material selected from optical ceramics, polycrystals, micro and nanocrystals, colloids of micro and nanocrystals, and composites of micro and nanocrystals in polymer or glassy matrices. The nonlinear optical material is prepared by modifying a microstructure of the initial sample of the NOE such that an average grain size is of the order of a coherence length of the three-wave interaction which enables the highest parametric gain achievable via the RQPM process.

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 visible light source includes a substrate, a vertical-cavity surface-emitting laser including an active semiconductor region configured to emit infrared light and a first reflector configured to reflect the infrared light emitted by the active semiconductor region, a second reflector configured to reflect the infrared light and form a vertical cavity for the infrared light with the first reflector, and one or more micro-resonators configured to receive the infrared light and generate visible light in one or more colors using the infrared light through optical parametric oscillation. The visible light source also includes one or more output couplers configured to couple the visible light in one or more colors from the one or more micro-resonators into free space or into a photonic integrated circuit.

Example methods, devices, and systems for optical emission are disclosed. An example device can comprise one or more optical filters. The one or more optical filters can be configured to be coupled to an optical amplifier. The device can comprise a microresonator configured to receive an output of the one or more optical filters and output, based on parametric multiwave mixing, a frequency comb. The one or more optical filters and the microresonator can be integrated into a single chip.

Technologies for a photon pair source integrated on a photonic die are disclosed. In an illustrative embodiment, a photonic die includes an integrated semiconductor laser. The integrated semiconductor laser pumps a Raman laser on the same die. The Raman laser has much lower noise near the laser peak compared to the semiconductor laser, due to a smaller gain bandwidth and less amplified stimulated emission. Due to the low noise, the Raman laser can be used to pump a spontaneous four-wave mixing (SFWM) source directly, without off-chip filtering required. The SFWM source can generate entangled photons with a high signal-to-noise ratio, with applications for quantum cryptography, quantum computing, and other quantum information processing tasks.