Transducers and methods of making the same include a substrate having a cavity with a diameter that supports whispering gallery modes at a frequency of an input signal. A focusing structure in the cavity focuses the electric field of the input signal. A resonator directly under the focusing structure has a crystalline structure that generates an electro-optic effect when exposed to electrical fields. An electric field of the input signal modulates an output signal in the resonator via the electro-optic effect.

An optical modulator is described. This optical modulator may be implemented using silicon-on-insulator (SOI) technology. In particular, the optical modulator may include a carrier-accumulation-type micro-disk resonator fabricated using optical waveguides having a composite structure. Moreover, the composite structure may embed a metal-oxide semiconductor capacitor in the disk resonator. For example, the composite structure may include polysilicon disposed on an oxide layer, which is disposed on a silicon layer in an SOI platform. The optical modulator may have high modulation efficiency and high-speed operation. In addition, the optical modulator may have a compact footprint with low power consumption.

There is provided a semi-circular resonator using a whispering gallery mode (WGM) and an optical sensor using the same. Accordingly, an active region that is a waveguide of an active layer in which laser oscillation is caused by gains of advancing beams is deeply etched in a semi-circular or semi-ring shape.

Systems and methods to stabilize a laser frequency include a birefringent resonator that introduces an arbitrary phase difference between two polarization components of the laser beam, a polarizing beam splitter to separate the two polarization components after the birefringent resonator, and a differential detector to monitor the separated two polarizations, based on which an error signal can be produced to control a servo to adjust the laser frequency or resonator resonance frequency accordingly. The birefringent resonator can comprise a fiber ring, a whispering gallery mode (WGM) resonator, or any other birefringent ring resonator. A servo can be included in the systems and methods to lock the laser frequency to the resonant frequency of the birefringent resonator or to lock the resonator resonant frequency to the laser frequency. One or more polarization controllers can also be employed to adjust the polarization state of the laser beam.

A device comprising: a substrate; a plurality of resonators on the substrate, each of the resonators of the plurality of resonators being resonant at a predetermined wavelength of electromagnetic radiation and at least some of the resonators being arranged to operate in different resonance orders; a waveguide on the substrate, the waveguide being coupled to the plurality of resonators for guiding the electromagnetic radiation to the plurality of resonators, wherein the resonance order of each resonator along the waveguide is optimized to maximize the coupling of light into the resonators.

Optical microresonator platforms are provided comprising a substrate having a surface, a plurality of SiO.sub.2 pillars, and a plurality of SiO.sub.2 whispering gallery mode (WGM) optical microresonators, each SiO.sub.2 pillar extending from the surface of the substrate and terminating in a corresponding SiO.sub.2 WGM optical microresonator of the plurality of SiO.sub.2 WGM optical microresonators, wherein the substrate, the plurality of SiO.sub.2 pillars and the plurality of SiO.sub.2 WGM optical microresonators form a monolithic structure, and further wherein the substrate is substantially transparent to visible light. The substrate may be a SiO.sub.2 substrate and the SiO.sub.2 WGM optical microresonator may be a SiO.sub.2 optical microtoroid.

A device for generating high optical quality (high-Q) highly twisted states of light and a method for quantitative estimating a loss at all wavelengths, includes: a waveguide configured to couple to a light source; and a microresonator coupled to the light source via the waveguide, wherein the microresonator operates in whispering gallery mode (WGM). The microresonator includes a photonic crystal ring (PhCR) configured to enable generating highly twisted states of light, and a photonic crystal grating.

A method includes applying a voltage to an optical ring resonator circuit to adjust a resonance condition of a ring waveguide included in the optical ring resonator circuit. The method also includes detecting an amount of current generated by the optical ring resonator circuit and determining the resonance condition of the ring waveguide based on the detected amount of current.

An optical modulator is described. This optical modulator may be implemented using silicon-on-insulator (SOI) technology. In particular, the optical modulator may include a carrier-accumulation-type micro-disk resonator fabricated using optical waveguides having a composite structure. Moreover, the composite structure may embed a metal-oxide semiconductor capacitor in the disk resonator. For example, the composite structure may include polysilicon disposed on an oxide layer, which is disposed on a silicon layer in an SOI platform. The optical modulator may have high modulation efficiency and high-speed operation. In addition, the optical modulator may have a compact footprint with low power consumption.

A resonant photonic device is provided. The device comprises an optical waveguiding element, such as an optical resonator, that includes a diode junction region, two signal terminals configured to apply a bias voltage across the junction region, and a heater laterally separated from the optical waveguiding element. A semiconductor electrical barrier element is juxtaposed to the heater. A metallic strip is electrically and thermally connected at one end to a signal terminal of the optical waveguiding element and thermally connected at another end to the barrier element.