Microring resonators are devices that includes a set of waveguides that guide light, where at least one of the waveguides is a closed loop that operates to increase an intensity of the light over each round-trip. Microring resonators can be configured to operate as light filters and/or light modulators, and have application, for example, in the field of optical communication technology. Due to temperature sensitivity of microring resonators, however, a heating device is needed to maintain a microring resonator at a desired temperature. The present disclosure provides a microring resonator heating device that includes at least two coaxially arranged contacts providing radial current flow to heat the microring resonator.

Optical whispering gallery mode (WGM) resonator-based acoustic sensors, imaging systems that make use of the acoustic sensors, and methods of detecting ultrasound waves using the acoustic sensors are disclosed.

The present invention relates to evanescently coupling whispering gallery mode optical resonators having a liquid coupling as well as methods of making and using same. The aforementioned evanescently coupling whispering gallery mode optical resonators having a liquid couplings provide increased tunability and sensing selectivity over current same. The aforementioned. Applicants' method of making evanescent-wave coupled optical resonators can be achieved while having coupling gap dimensions that can be fabricated using standard photolithography. Thus economic, rapid, and mass production of coupled WGM resonators-based lasers, sensors, and signal processors for a broad range of applications can be realized.

A method for fabricating a thick crack-free dielectric film on a wafer for device fabrication is disclosed herein. A stress-release pattern is fabricated in an oxide layer of the wafer, which surrounds a number of device regions. The stress-release pattern comprises a plurality of recessions, which are spaced periodically along at least one direction. The plurality of recessions interrupt the continuous film during the dielectric film deposition, to prevent cracks from forming in the dielectric film and propagating into the device regions. Such that, a thick crack-free dielectric film can be achieved in the device regions, which are formed by patterning the dielectric layer. Furthermore, conditions of the dielectric film deposition process can be tuned to ensure quality of the deposited dielectric film. Still further, a plurality of deposition runs may be performed to deposit the thick crack-free dielectric film.

Photonic chip includes an external cavity (EC) optical circuit to provide wavelength-selective optical feedback to a length of active optical fiber. Light generated in the active optical fiber may be coupled from the EC circuit to a light processing circuit of the photonic chip, such as an optical modulator or an optical mixer. The EC circuits may include single-frequency and multi-frequency optical filters, which may include ring resonators, dual-ring resonators, and optical modulators to support multi-frequency lasers. The EC circuits may further include pump combiners and optical isolators.

A device includes a substrate, a dielectric layer on the substrate, a waveguide within the dielectric layer, and a photodetector optically coupled to the waveguide. The photodetector is disposed above the waveguide layer and is monolithically integrated with the substrate. The photodetector is configured to operate at low temperatures, such as below about 50 K or about 20 K. In some embodiments, the monolithic photonic device includes thermal isolation structures and optical isolation structures. Techniques for manufacturing the monolithic photonic device, including the thermal isolation structures and optical isolation structures, are also described.

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.

The present invention relates to evanescently coupling whispering gallery mode optical resonators having a liquid coupling as well as methods of making and using same. The aforementioned evanescently coupling whispering gallery mode optical resonators having a liquid couplings provide increased tunability and sensing selectivity over current same. The aforementioned. Applicants' method of making evanescent-wave coupled optical resonators can be achieved while having coupling gap dimensions that can be fabricated using standard photolithography. Thus economic, rapid, and mass production of coupled WGM resonators-based lasers, sensors, and signal processors for a broad range of applications can be realized.

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.

Tapered waveguides made of high-index material attached to a tapered optical fiber are provided, enabling access to the optical modes of large, high-index resonators. In some embodiments, an optical fiber having a central axis, a tapered portion, and an untapered portion is provided. The tapered portion is configured to expose an evanescent field. An elongated waveguide is optically coupled to the optical fiber along the tapered portion and parallel to the central axis of the optical fiber. The elongated waveguide has a substantially triangular cross section perpendicular to the central axis of the optical fiber.