A system for generating a coherent laser light includes a light source configured to pump a first color laser light and a device configured to generate a coherent second color light and a coherent third color light. The device includes a waveguide configured to couple to the light source and a microring resonator coupled to the light source via the waveguide. The microring resonator is configured to generate a coherent second color light and a coherent third color light. The generation of the coherent second color light and the coherent third color light is based on hybrid-mode optical parametric oscillation.

An optical waveguide structure comprises a nonlinear optical waveguide, a set of tuning optical waveguides, a set of wavelength selective couplers that couples light between the nonlinear optical waveguide and one or more tuning optical waveguides in the set of tuning optical waveguide based on a wavelength of light, and a set of phase shifters located along one or more tuning optical waveguides in the set of tuning optical waveguides.

A miniaturized PPKTP crystal-based entanglement source system using multi-mode reception is provided, which includes a pump light source, a pump light transmission module, an entanglement device, a first collection device, and a second collection device. In the entanglement source system, entangled lights are received by using multi-mode optical fibers, and an entangled light processing scheme of combining a temporal filtering technology and a spatial filtering technology is applied into a collecting device at one side of the entanglement source system, to form asymmetric device structures in the entanglement source system, to enable multi-mode reception.

An optical-resolution photoacoustic microscopy (OR-PAM) system for visualizing water content deep in biological tissue uses an all-fiber 1930-nm hybrid optical parametrically-oscillating emitter. The emitter includes a tunable laser source whose output is amplified by a first erbium-doped fiber amplifier (EDFA). The output of the first amplifier is modulated with a Mach-Zehnder amplitude modulator that receives an RF signal with a nanosecond pulse width and a multiple kilohertz repetition rate. A second EDFA further amplifies the signal and passes it to a fiber circulator that in turn delivers it to a 1950/1550 mm fiber wavelength-division-multiplexing coupler WDM. The coupler introduces the signal to a cavity that includes a spool of highly nonlinear fiber and a Thulium-doped fiber amplifier TDFA. From the TDFA the signal reaches a 50/50 fiber coupler that sends part to a second output TDFA and guides part back to the cavity through a port of the WDM.

A microwave-to-optical photon transducer is provided for generating coupling between a microwave signal (S.sub.in2) and an optical signal (S.sub.pi_in1, S.sub.pi_out1). The transducer comprises: a first input port; a second input port; a first output port for outputting the optical signal (S.sub.pi_out1) and one or more optical sideband signals (S.sub.out1, S.sub.out11, S.sub.out12); a first waveguide disposed between the first input port and the first output port to allow the optical signal (S.sub.pi_in1) and the one or more optical sideband signals (S.sub.out1, S.sub.out11, S.sub.out12) to propagate in the first waveguide; a second waveguide connected to the second input port, and extending in the transducer adjacent to the first waveguide to allow the microwave signal (S.sub.in2) to propagate in the second waveguide; a phase-matching arrangement to cause at least the optical signal (S.sub.pi_in1) and the microwave signal (S.sub.in2) to be phase-matched or quasi-phase-matched.

An optical waveguide structure comprises a nonlinear optical waveguide comprising a set of segments, a set of extension optical waveguides, and a set of wavelength selective couplers that couples light between set of segments in the nonlinear optical waveguide and the set of extension optical waveguides based on a wavelength of light.

A coherent anti-stokes Raman scattering apparatus for imaging a sample includes an optical output; an optical source arranged to generate a first optical signal at a first wavelength; and a nonlinear element arranged to receive the first optical signal, where the nonlinear element is arranged to cause the first optical signal to undergo four-wave mixing on transmission through the nonlinear element such that a second optical signal at a second wavelength and a third optical signal at a third wavelength are generated, wherein an optical signal pair including two of the first, second and third optical signals is provided to the optical output for imaging the sample.

A tunable parametric mixer comprising a pump laser, a nonlinear waveguide, and a refractive index tuner. The pump laser is configured to generate pump photons. The nonlinear waveguide comprises a cladding and a core. The core is made of nonlinear optical material and the cladding in made of a material with a tunable index of refraction. The nonlinear waveguide is configured to convert the pump photons into signal and idler photons. The refractive index tuner is configured to change the refractive index of the cladding to dynamically tune the dispersion properties of the nonlinear waveguide in order to alter a spectral location of a gain band of the parametric mixer.

A high-efficiency non-collinearly phase matched parametric oscillator is provided, wherein a laser pumps a nonlinear optical material with a plural number of flat reflection surfaces that zigzag at least one parametrically generated off-axis radiation about the pump laser beam axis via multiple reflections from the surfaces. The off-axis zigzag oscillation of the radiation establishes parametric oscillation and improves energy coupling among mixing waves in a monolithic nonlinear optical material. Preferably the pump laser has a transverse beam size covering the area of the zigzagging parametrically generated radiation. To further enhance the performance of the off-axis zigzag parametric oscillator, the other parametrically generated radiation can be seeded by an external laser source or resonated in a cavity. The present invention also includes a double-side pumped off-axis zigzag parametric oscillator installed inside a standing-wave pump-laser cavity.

A quantum state measurement system includes a quantum state generator that generates an optical photon comprising a quantum state. A spectral converter modifies a spectrum of the optical photon and provides the optical photon comprising the quantum state with the modified spectrum. An optical switch switches the optical photon with the modified spectrum to one of a plurality of outputs. A measurement system determines a fidelity of the quantum state of the optical photon with the modified spectrum. A control system provides an electrical control signal to the quantum state generator in response to the determined fidelity of the quantum state that improves a fidelity of at least some subsequent generated optical photons comprising a quantum state that are generated by the quantum state generator after the optical photon.