An FM LIDAR system is described that includes a frequency modulated LIDAR system that incorporates a laser source that is optically coupled to a whispering gallery mode optical resonator. Light from the laser that is coupled into the whispering gallery mode optical resonator is coupled back out as a returning counterpropagating wave having a frequency characteristic of a whispering gallery mode of the optical resonator. This returning wave is used to reduce the linewidth of the source laser by optical injection. Modulation of the optical properties of the whispering gallery mode optical resonator results in modulation of the frequency of the frequencies supported by whispering gallery modes of the resonator, and provides a method for producing highly linear and reproducible optical chirps that are highly suited for use in a LIDAR system. Methods of using such an FM LIDAR system and vehicle assisting systems that incorporate such FM LIDAR systems are also described.

A method for designing a non-circular dielectric resonator is provided. The method includes obtaining a conformal transformation coordinate of the non-circular dielectric resonator to correspond to a rectangular coordinate system of a circular dielectric resonator, mapping the obtained conformal transformation coordinate to the non-circular dielectric resonator, and setting a refractive index in the non-circular resonator and allowing an incident angle of light to satisfy a condition for total reflection in each of boundary areas in a non-circular dielectric resonator to which the conformal transformation coordinate is mapped.

A modulated light source includes a reflective semiconductor optical amplifier including a mirror at a first end of the reflective semiconductor optical amplifier, a modulator configured to modulate a central wavelength, a first mirror configured to reflect light transmitted by the modulator, an optical filter disposed between a second end of the reflective semiconductor optical amplifier and the modulator, and a second mirror configured to reflect part of incoming light and to transmit the other part of the incoming light. The reflective semiconductor optical amplifier, the optical filter, and the second mirror configure a Fabry-Perot laser. The first mirror is configured to feed light emitted from the Fabry-Perot laser back to the Fabry-Perot laser, and the modulated light source is configured to select light corresponding to one of longitudinal modes oscillated by the Fabry-Perot laser, to modulate the selected light, and to output the modulated light.

Back scattering in an optical waveguide at an operating wavelength is controlled by adjusting an optical phase of light propagating in the waveguide at one or more locations along the waveguide. A portion of the back scattered light is tapped off near an input port and coupled into a photodetector. A controller detects changes in the photodetector signal and adjusts an optical phase tuner configured to control the optical phase of light in the waveguide at the selected location or locations. The optical phase tuner may be configured to vary the refractive index of at least a portion of the waveguide.

A tunable, all-optical, coupling method for a high-Q silica microsphere and an optical waveguide is disclosed. By means of a novel optical nanopositioning method, induced thermal expansion of an asymmetric microsphere stem for laser powers up to 211 mW is observed and used to fine tune the microsphere-waveguide coupling. Microcavity displacements ranging from (0.610.13)-(3.490.13) m and nanometer scale sensitivities varying from (2.810.08)-(17.080.76) nm/mW are obtained. Additionally, an apparent linear dependency of coupling distance on stem laser heating is achieved. Using these methods, coupling can be altered such that the differing and customizable coupling regimes can be achieved.

A tunable, all-optical, coupling method for a high-Q silica microsphere and an optical waveguide is disclosed. By means of a novel optical nanopositioning method, induced thermal expansion of an asymmetric microsphere stem for laser powers up to 211 mW is observed and used to fine tune the microsphere-waveguide coupling. Microcavity displacements ranging from (0.610.13)(3.490.13) m and nanometer scale sensitivities varying from (2.810.08)(17.080.76) nm/mW are obtained. Additionally, an apparent linear dependency of coupling distance on stem laser heating is achieved. Using these methods, coupling can be altered such that the differing and customizable coupling regimes can be achieved.

An optical system can automatically lock an adjustable spectral filter to a first wavelength of an incoming light signal, and can automatically filter an additional incoming light signal at the first wavelength. A tunable filter can have a filtering spectrum with an adjustable peak wavelength and increasing attenuation at wavelengths away from the adjustable peak wavelength. The tunable filter can receive first input light, having a first wavelength, and can spectrally filter the first input light to form first output light. A detector can detect at least a fraction of the first output light. Circuitry coupled to the detector and the tunable filter can tune the tunable filter to maximize a signal from the detector and thereby adjust the peak wavelength to match the first wavelength. The tunable filter further can receive second input light and spectrally filter the second input light at the first wavelength.

An optical sensor includes an optical device including a microresonator, laid out to guide a light beam along a closed loop optical path, and an injection and/or extraction waveguide, optically coupled to the microresonator; a photodetector, arranged at the output of the injection and/or extraction waveguide; and an analysis device, receiving a signal supplied by the photodetector, and deducing therefrom information relative to a displacement. The microresonator is constituted of a plurality of elementary waveguides spaced apart from each other, and arranged one after the other according to a loop shaped layout. The optical sensor offers increased sensitivity to the measurement of nanometric displacements.

A passive mode-locked laser method and system, the system comprising a nonlinear optical loop comprising a resonant nonlinear element, coupled to an amplification section by a beam splitter, the beam splitter splitting a light beam from the amplification section into light beams propagating in opposite directions around the nonlinear optical loop, the resonant nonlinear element acting as both a nonlinear element and a narrow bandwidth filter for the laser system, allowing mode-locking operation of the system on a single resonance of the resonant nonlinear element.

An FM LIDAR system is described that includes a frequency modulated LIDAR system that incorporates a laser source that is optically coupled to a whispering gallery mode optical resonator. Light from the laser that is coupled into the whispering gallery mode optical resonator is coupled back out as a returning counterpropagating wave having a frequency characteristic of a whispering gallery mode of the optical resonator. This returning wave is used to reduce the linewidth of the source laser by optical injection. Modulation of the optical properties of the whispering gallery mode optical resonator results in modulation of the frequency of the frequencies supported by whispering gallery modes of the resonator, and provides a method for producing highly linear and reproducible optical chirps that are highly suited for use in a LIDAR system. Methods of using such an FM LIDAR system and vehicle assisting systems that incorporate such FM LIDAR systems are also described.