Abstract: The disclosure relates in some aspects to providing miniature power-efficient agile photonic generators of microwave waveforms. Illustrative examples use chip lasers integrated in close thermal proximity with one another to provide a miniature microwave arbitrary waveform generator (AWG). Due to the small size of the lasers and the close integration, common ambient fluctuations from the environment or other sources can be efficiently reduced, yielding improved spectral purity of generated radio-frequency (RF) signals. Tight physical integration also permits a small device footprint with minimal acceleration sensitivity. The lasers may be locked to cavities or other resonators to allow efficient decoupling of the frequency and amplitude modulation of the lasers to provide flexibility to the waveform generator. Exemplary devices described herein can produce frequency chirped signals for radar applications. The frequency chirp may be linear and/or nonlinear. Tuning methods are also described herein.

Abstract: The disclosure relates in sonic aspects to a radar device utilizing frequency modulated continuous waves (FMCW) to illuminate a target. The device uses two or more fixed transmitter antennas spaced apart to provide high resolution imaging with fast resolution time. In one example, the radar device includes: a signal source providing a transmission signal; a first transmitter for transmitting the signal as a first FMCW to a target; a second transmitter for transmitting the signal as a second FMCW to the target, where the first and second transmitters are spaced apart by a distance greater than a wavelength of the transmission signal; a receiver for receiving a reflected signal from the target; and an analyzer for determining the target distance and angle of the target with respect to the transmitters based on the received signal and the transmission signal. Radar devices with multiple input, multiple output transmitters are also described.

Abstract: The disclosure relates in some aspects to providing miniature power-efficient agile photonic generators of microwave waveforms. Illustrative examples use chip lasers integrated in close thermal proximity with one another to provide a miniature microwave arbitrary waveform generator (AWG). Due to the small size of the lasers and the close integration, common ambient fluctuations from the environment or other sources can be efficiently reduced, yielding improved spectral purity of generated radio-frequency (RF) signals. Tight physical integration also permits a small device footprint with minimal acceleration sensitivity. The lasers may be locked to cavities or other resonators to allow efficient decoupling of the frequency and amplitude modulation of the lasers to provide flexibility to the waveform generator. Exemplary devices described herein can produce frequency chirped signals for radar applications. The frequency chirp may be linear and/or nonlinear. Tuning methods are also described herein.

Abstract: The disclosure relates in some aspects to an open dielectric resonator with nanoparticles secured on its outer surface, where the nanoparticles are located, sized and/or shaped to increase an amount of backscattered light in the resonator to provide substantially lossless, coherent backscattering of light. In some examples, fine particles are used instead of nanoparticles. Other features relate to a laser system having a plasmon-activated cavity optically coupled to a laser where the plasmon-activated cavity is configured to (a) receive a laser beam, (b) scatter the laser beam in accordance with a plasmon resonance, and (c) feed at least a portion of the laser beam back to the laser for self-injection locking of the laser. The plasmon-activated cavity may be a dielectric resonator with surface particles configured to stabilize the laser to a frequency of a plasmon mode to reduce a linewidth of the laser.

Abstract: An optical atomic clock utilizing two different laser light sources is described. A source laser is locked to a first optical resonator, which supports a whispering gallery mode for the source laser and generates optical hyperparametric sidebands from the source laser output by multi-wave mixing. A reference laser is locked to an atomic reference via a second optical resonator, and the first optical resonator is locked to the reference laser. Optical parametric sidebands, which are locked to an atomic reference but are generated from a wavelength unrelated to the clock transition of the atomic reference, are coupled out of the first optical resonator to generate an RF signal useful in atomic timekeeping.

Abstract: An optical atomic clock utilizing two different laser light sources is described. A source laser is locked to a first optical resonator, which supports a whispering gallery mode for the source laser and generates optical hyperparametric sidebands from the source laser output by multi-wave mixing. A reference laser is locked to an atomic reference via a second optical resonator, and the first optical resonator is locked to the reference laser. Optical parametric sidebands, which are locked to an atomic reference but are generated from a wavelength unrelated to the clock transition of the atomic reference, are coupled out of the first optical resonator to generate an RF signal useful in atomic timekeeping.

Abstract: A monolithic resonator that has a plurality of mode families is modified so that portions of the resonator have a different index of refraction than other portions of the resonator. This degrades the Q factor of one or more of the mode families, allowing pre-selection of one or more mode families over others.

Abstract: Optical filters comprising one or more optically-coupled Fabry-Perot resonators are disclosed. In some embodiments, the one or more optically coupled Fabry-Perot resonators include a graded index fiber. In some embodiments, the one or more optically coupled Fabry-Perot resonators are coupled end-to-end, whereas in other embodiments the one or more optically coupled Fabry-Perot resonators are side-coupled through evanescence. One or more implementations of an optical filter allow a spectral response of an input light beam to be controlled, through various approaches, e.g., by exposing a component fiber to ultra-violet radiation.

Abstract: Optical filters comprising one or more optically-coupled Fabry-Perot resonators are disclosed. In some embodiments, the one or more optically coupled Fabry-Perot resonators include a graded index fiber. In some embodiments, the one or more optically coupled Fabry-Perot resonators are coupled end-to-end, whereas in other embodiments the one or more optically coupled Fabry-Perot resonators are side-coupled through evanescence. One or more implementations of an optical filter allow a spectral response of an input light beam to be controlled, through various approaches, e.g., by exposing a component fiber to ultra-violet radiation.

Abstract: A monolithic resonator that has a plurality of mode families is modified so that portions of the resonator have a different index of refraction than other portions of the resonator. This degrades the C) factor of one or more of the mode families, allowing pre-selection of one or more mode families over others.

Abstract: Opto-electronic oscillator (OEO) devices include an optical resonator filter to block the strong laser light at the laser carrier frequency from entering the optical resonator filter and to select one of the weak modulation sidebands, which is in resonance with the optical resonator filter, to be coupled into the optical resonator filter. The laser light at the laser carrier frequency and other modulation sidebands bypass the optical resonator filter to reach a fast photodetector. The laser light in the selected modulation sideband in the optical resonator filter is then coupled out to mix with the laser light at the laser carrier frequency and other modulation sidebands at the fast photodetector to produce the detector output as the input to the electrical part of the opto-electronic loop to produce the OEO oscillation.

Abstract: Techniques and devices based on optical resonators made of nonlinear optical materials and nonlinear wave mixing to generate optical combs that are stabilized relative to an atomic reference.

Abstract: Techniques, devices and systems that stabilize an RF oscillator by using an optical resonator that is stabilized relative to a master RF oscillator with acceptable frequency stability performance. In the examples described, the optical resonator is stabilized relative to the master RF oscillator by using a frequency stability indicator based on two different optical modes of the optical resonator. The RF oscillator to be stabilized is then locked to the stabilized optical resonator to achieve the acceptable RF stability in the RF oscillator.

Abstract: This document provides techniques, apparatus and designs for using electro-optic WGM resonators that support two different families of optical WGM modes with different quality factors in various applications. A radio frequency (RF) resonator is formed on the optical resonator and structured to supply an RF field and spatially overlaps the RF field of the RF resonator with the first and second optical whispering gallery modes to cause RF energy in the RF field at a first RF carrier frequency to couple with the first optical whispering gallery mode and RF energy in the RF field at a second RF carrier frequency to couple with the second optical whispering gallery mode.

Abstract: Techniques and devices that lock and stabilize a laser to an optical resonator via self-injection locking based on a reflection feedback. A whispering gallery mode optical resonator can be implemented to provide both the optical filtering and injection feedback based on the reflection feedback from feedback optics outside the optical resonator.

Abstract: Techniques and devices for providing optical locking of optical resonators and lasers.

Abstract: Photonic devices and techniques based on tunable single sideband (SSB) modulation in whispering gallery mode resonators formed of different poled electro-optic domains and to support whispering gallery modes circulating in the optical resonator to effectuate a single sideband (SSB) on only one side of the laser frequency without having a mirror image sideband on the other side of the laser frequency.

Abstract: Opto-electronic oscillator (OEO) devices include an optical resonator filter to block the strong laser light at the laser carrier frequency from entering the optical resonator filter and to select one of the weak modulation sidebands, which is in resonance with the optical resonator filter, to be coupled into the optical resonator filter. The laser light at the laser carrier frequency and other modulation sidebands bypass the optical resonator filter to reach a fast photodetector. The laser light in the selected modulation sideband in the optical resonator filter is then coupled out to mix with the laser light at the laser carrier frequency and other modulation sidebands at the fast photodetector to produce the detector output as the input to the electrical part of the opto-electronic loop to produce the OEO oscillation.

Abstract: This document provides techniques, apparatus and designs for using electro-optic WGM resonators that support two different families of optical WGM modes with different quality factors in various applications. A radio frequency (RF) resonator is formed on the optical resonator and structured to supply an RF field and spatially overlaps the RF field of the RF resonator with the first and second optical whispering gallery modes to cause RF energy in the RF field at a first RF carrier frequency to couple with the first optical whispering gallery mode and RF energy in the RF field at a second RF carrier frequency to couple with the second optical whispering gallery mode.

Abstract: Optical gyroscope devices based on optical whispering gallery mode resonators that measure rotations based on rotation-induced optical phase shift in optical whispering gallery mode resonators.