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 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 silicon modulator where the doping profile varies along the lateral and/or longitudinal position in the transition zones to achieve improved performance in terms of optical attenuation or contact access resistance or both. A modulator includes a core; a first transition zone that is a P-side region adjacent to the waveguide core, the first transition zone has a first longitudinal doping profile; and a second transition zone that is an N-side region adjacent to the core on an opposite side as the first transition region, the second transition zone has a second longitudinal doping profile; the first longitudinal doping profile has a variation of doping concentration along a longitudinal direction in the first transition region to mimic a first lateral doping profile, and the second longitudinal doping profile has a variation of doping concentration along a longitudinal direction in the second transition region to mimic a second lateral doping profile.

A silicon modulator where the doping profile varies along the lateral and/or longitudinal position in the transition zones to achieve improved performance in terms of either optical attenuation or contact access resistance or both. A silicon-based modulator includes a waveguide core that is a PN junction region; a first transition zone that is a P-side region adjacent to the waveguide core and a first electrode; and a second transition zone that is an N-side region adjacent to the waveguide core on an opposite side as the first transition region and a second electrode; wherein a thickness of each of the first transition zone and the second transition zone is variable in any of a lateral direction, a longitudinal direction, and both the lateral direction and the longitudinal direction, each of the lateral direction and the longitudinal direction are relative to the waveguide core.

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.

Aspects of the disclosure provide a system and method used for time-of-flight lidar applications. Such systems and methods include a laser and pulse clipper which produces a shuttering effect to reduce the instantaneous output power from the pulse clipper. Accordingly the output from the pulse clipper is more suitable for time-of-flight lidar applications than that initially produced by the laser. This can allow for lasers which may otherwise exceed eye safety limits to be used for time-of-flight lidar applications without exceeding the eye safety limits.

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.

A core, constituted by an amorphous undoped semiconductor (i type), which is formed on a lower clad layer, and a p-type layer and an n-type layer which are disposed on the lower clad layer with the core interposed therebetween and are formed in contact with the core are provided. The core is formed to be thicker than the p-type layer and the n-type layer. The p-type layer and the n-type layer are constituted by single crystal silicon.

An optical modulating device may include a plurality of quantum dot (QD)-containing layers having QDs and a plurality of refractive index change layers. The QD-containing layers may be disposed between the refractive index change layers, respectively. The optical modulating device may be configured to modulate light-emission characteristics of the plurality of QD-containing layers. At least two of the QD-containing layers may have different central emission wavelengths. At least two of the plurality of refractive index change layers may include different materials or have different carrier densities.