Ring modulators based on interdigitated junctions may be driven in full or partial standing wave mode and, active regions (providing the modulation) and light-absorptive regions (e.g. providing electrical conduction) are placed in a pattern inside a resonant cavity in order to match the maxima and minima of the optical field, respectively. The pattern may be periodic to match the periodicity of a typical electromagnetic field which is periodic with the wavelength. It may also be aperiodic in the case that the cross-section or materials are engineered along the direction of propagation such that the propagation constant (and thus wavelength, i.e. optical wave local periodicity) change along the propagation direction.

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.

A phase shifting optical device and method of manufacture is provided. In an embodiment, the phase shifting optical device may include a first arm defining a first arm optical path, a second arm defining a second arm optical path, a beam splitter for splitting an input optical beam into first and second sub-beams for propagating in the first and second arm optical paths, respectively, and a beam combiner for combining the first and second sub-beams propagated in the first and second arm optical paths, respectively, into an output optical beam. The first arm including a carrier modification element to induce a phase shift in the first arm optical path relative to the second arm optical path. A cladding may be provided proximate to the first arm, the cladding having a temperature coefficient of refractive index (dn/dT)cl opposite in sign to a temperature coefficient of refractive index (dn/dT)a of the first arm.

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 modulator includes a waveguide core; a first transition zone located between a first side of the waveguide core and a first electrical contact region; and a second transition zone located between a second side of the waveguide core and a second electrical contact region, wherein one or more of the first transition zone and second transition zone has a variable thickness. The variable thickness is confined to the one or more of the first transition zone and second transition zone. The variable thickness removes a portion of the highly doped first transition zone and the highly doped second transition zone thereby reducing contact resistance.

Disclosed are designs and methods of fabrication of silicon carrier-depletion based electro-optical modulators having doping configurations that produce modulators exhibiting desirable modulation efficiency, optical absorption loss and bandwidth characteristics. The disclosed method of fabrication of a modulator having such doping configurations utilizes counter doping to create narrow regions of relatively high doping levels near a waveguide center.

Disclosed is a photonic beam forming network chip using silicon semiconductor based monolithic integration for fabrication and using true time delay for signal processing of a phased array antenna, including at least one power splitter a plurality of Mach-Zehnder modulators, a plurality of true time delay devices, a photonic detector, and a photonic waveguide configured to respectively connect the at least one power splitter, the plurality of Mach-Zehnder modulators, the plurality of true time delay devices, and the photonic detector.

Disclosed are designs and methods of fabrication of silicon carrier-depletion based electro-optical modulators having doping configurations that produce modulators exhibiting desirable modulation efficiency, optical absorption loss and bandwidth characteristics. The disclosed method of fabrication of a modulator having such doping configurations utilizes counter doping to create narrow regions of relatively high doping levels near a waveguide center.

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.

A tuning method for active metamaterials using IGZO Schottky diodes, wherein the IGZO Schottky diode comprises a substrate, a Schottky electrode, amorphous IGZO active layer, and an ohmic electrode from the bottom up. The method comprises steps as follows: (1) Metamaterials are used as the Schottky electrodes, and amorphous IGZO active layers are used to fully cover the capacitive gap structures in the metamaterials; such capacitive structures in the metamaterials are bonded to the amorphous IGZO active layers to form Shottky barriers; (2) The resulting IGZO Schottky diodes from step (1) are used to tune the metamaterials dynamically.