The method for manufacturing the heterojunction circuit according to one embodiment of the present disclosure comprises depositing a first electrode on at least a part of a waveguide, moving a semiconductor comprising a second electrode at a lower end thereof onto the first electrode, and depositing a third electrode on an upper end of the semiconductor, wherein the waveguide and the semiconductor comprise different materials. Additionally, the moving step further comprises generating microbubbles by supplying heat to at least a part of the semiconductor, moving the semiconductor on the first electrode by moving the generated microbubbles, and removing the microbubbles by positioning the semiconductor on the first electrode.

An optical coupling device is described herein. The optical coupling device comprises a first waveguide and a second waveguide that are formed on a common substrate, and a resonator that is positioned out of plane with the two waveguides. The resonator and waveguides are positioned such that light traveling in each of the waveguides evanescently couples to the resonator but not to the other of the waveguides. The optical coupling device can be used in connection with improving linewidth of a laser source for a lidar sensor. In another example, the optical coupling device can be used in connection with wavelength division multiplexing.

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 method for manufacturing of a waveguide for guiding an electro-magnetic wave comprising: forming a first waveguide layer, a sacrificial layer and a protection layer on a first wafer, patterning to define a pattern of a first waveguide part and a supporting structure in the first waveguide layer; exposing the sacrificial layer on the first waveguide part while the protection layer still covers the sacrificial layer on the supporting structure; removing the sacrificial layer on the first waveguide part; removing the protection layer; bonding a second wafer to the sacrificial layer of the first wafer such that a second waveguide part is supported by the supporting structure and a gap corresponding to the thickness of the sacrificial layer is formed between the first and second waveguide parts.

An optical coupling device is described herein. The optical coupling device comprises a first waveguide and a second waveguide that are formed on a common substrate, and a resonator that is positioned out of plane with the two waveguides. The resonator and waveguides are positioned such that light traveling in each of the waveguides evanescently couples to the resonator but not to the other of the waveguides. The optical coupling device can be used in connection with improving linewidth of a laser source for a lidar sensor. In another example, the optical coupling device can be used in connection with wavelength division multiplexing.

A wavelength calibration method, apparatus, and system is disclosed. The method includes: selecting sonic wavelengths from a plurality of wavelengths, and performing the following operations on a microring filter for each of the some wavelengths, to obtain sets of calibrated voltages of the some wavelengths: (1) adjusting thermal tuning power of multiple microrings by using one set of voltages, and obtaining multiple sets of voltages that enable monitored optical power to have an extreme value, and (2) using the multiple of sets of voltages as a reference, adjusting the thermal tuning power of the multiple microrings by using another set of voltages, and determining one of the sets of calibrated voltages, which enables the monitored optical power to converge, from the multiple sets of voltages; and then, obtaining, through calculation based on the sets of calibrated voltages of the some wavelengths, sets of calibrated voltages of other wavelengths.

One feature pertains to an apparatus that includes apparatus that includes an evanescent field coupler having a first surface that evanescently couples light between the evanescent field coupler and an open dielectric resonator. The apparatus also includes a thin film coating covering at least a portion of the first surface of the evanescent field coupler. The thin film coating is specifically designed so that the thin film coating reflects light of a 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.

The method for manufacturing the heterojunction circuit according to one embodiment of the present disclosure comprises depositing a first electrode on at least a part of a waveguide, moving a semiconductor comprising a second electrode at a lower end thereof onto the first electrode, and depositing a third electrode on an upper end of the semiconductor, wherein the waveguide and the semiconductor comprise different materials. Additionally, the moving step further comprises generating microbubbles by supplying heat to at least a part of the semiconductor, moving the semiconductor on the first electrode by moving the generated microbubbles, and removing the microbubbles by positioning the semiconductor on the first electrode.

A tunable laser includes a reflective semiconductor optical amplifier (SOA), a grating codirectional coupler, and a reflective microring resonator. The grating codirectional coupler and the reflective microring resonator are both formed on a silicon base. An anti-reflection film is disposed on a first end surface of the reflective SOA, and the first end surface is an end surface, coupled to a first waveguide of the grating codirectional coupler, of the reflective SOA. A second waveguide of the grating codirectional coupler is coupled to the first waveguide, a first grating is disposed on the first waveguide, a second grating disposed opposite to the first grating is disposed on the second waveguide, and the first grating and the second grating constitute a narrow-band pass filter. The second waveguide is connected to the reflective microring resonator.