Abstract: A dual Lidar-radar sensor instrument based on a photonic implementation. The instrument employs two continuous wave lasers that concurrently provide an optical Lidar signal and a microwave radar signal, via a high bandwidth photodetector, for inherent coherence of Lidar and radar functions for data fusion and other purposes. In illustrative examples, the photonic system is integrated as a photonic integrated circuit (PIC).

Abstract: A photonic system enabling the processing of high frequency microwave, mm-wave, THz signals or other RF signals. The processing may include, e.g., adjusting the frequency, quadrature, and/or power of the signals. In illustrative examples, the system uses a polychromatic light source producing at least two low noise optical emission frequencies that can be independently tuned in a broad frequency range and/or modulated in a broad frequency range using external modulators. An RF input signal is upconverted to one of the optical harmonics of the modulated polychromatic source, processed in the optical frequency domain, and downconverted to the RF domain (at the same or a different RF carrier frequency). The photonic system can be integrated on a planar optical substrate, such as a photonic integrated circuit (PIC). Optical local oscillators are also described for use in the photonic system or for other purposes. Various system, device, and method examples are provided.

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: A photonic synthesizer includes a multifrequency optical source to produce a signal of interest from a pair of lasers, which may be self-injection locked chip lasers. The signal is referenced to a high frequency clock using a photonic mixer/divider based on an electro-optical modulator and a relatively slow photodiode. The electro-optical modulator produces optical harmonics from the beams from the pair of lasers, where one harmonic from the first laser beam and one harmonic from the second laser beam beat on the photodiode. A phase locked control signal is generated for controlling the output frequency of one or both of the two lasers. The output signal of the photonic synthesizer is generated using a relatively fast photodiode based on a difference in frequencies of the pair of lasers. The output signal may be a millimeter wave-band signal. The photonic synthesizer can be formed as a photonic integrated circuit (PIC).

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: Techniques and devices for measuring phase noise in radio frequency (RF), microwave, or millimeter signals based on photonic delay.

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: Signal filter designs and techniques use a signal filter of a given order to achieve a higher order filter operation than what the filter is designed for. In various implementations, the present signal filter designs and techniques allow achieving desired high order filter operation without using a high order filter. Specific examples are provided to use a double pass configuration to feed a once filtered signal by a filter back to the filter to filter the feedback signal for the second time and a Sagnac interferometer configuration to cause interference between two once filtered signals.

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: An external cavity laser comprises a gain medium and an external cavity resonator without the use of a semi-reflective surface placed between the gain medium and the resonator. Radiation from the gain medium is reflected back to the gain medium by one or more resonant backscattering regions of the resonator, such that the entire optical path between the gain medium and the external cavity resonator could be free from a reflective surface.

Abstract: A light spectrum generator uses an input continuous light source well within the normal GVD of a resonator to produce a multi-wavelength spectrum having irregularly spaced harmonics that could span wavelengths of more than six octaves from one another. Combined with a tuner that adjusts the power and wavelength of the light source, a turner that adjusts a temperature or a pressure applied to the resonator, and a filter, the generator could be used to produce any wavelength of light between 0.1 and 10 ?m.

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: Examples and implementations of reconfigurable sensors in a sensor array for performing various reconfigurable sensing functions.

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 based on optical resonators made of nonlinear optical materials to form triple-oscillator devices for generating a single optical tone, a radio frequency (RF) oscillation signal and an optical frequency comb signal having different optical frequencies.

Abstract: Techniques and devices based on optical resonators made of nonlinear optical materials and nonlinear wave mixing to generate RF or microwave oscillations using an active opto-electronic loop.

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.