An optical modulator is disclosed, in which a MMI couplers are used for input signal splitting for branching into individual Mach-Zehnder interferometers, as well as for branching and combining from individual Mach-Zehnder waveguides. MMI couplers, splitters, and combiners may be cascaded and combined with single-mode Y-splitters and combiners to provide modulators of various types, including dual polarization, quadrature phase Mach-Zehnder interferometer base optical modulators.

An optical modulator includes an optical splitter splitting input optical signals into a first optical signal and a second optical signal and transmitting the first optical signal and the second optical signal to a first optical waveguide and a second optical waveguide, respectively, an optical combiner generating an output optical signal by combining the first and second optical signals transmitted from the first and second optical waveguides respectively, and including three output ports including a main output port, a first auxiliary output port, and a second auxiliary output port, three output optical waveguides connected to the three output ports, respectively, and transmitting the output optical signal, and an optical detector connected to at least one of the three output optical waveguides.

A polarization beam splitter includes an input port, first and second output ports, and a polarization splitting region coupled between the input port and the first and second output ports. The input port is adapted to receive guided optical signals that are polarization multiplexed, including a transverse electric (TE) optical signal and a transverse magnetic (TM) optical signal. The polarization splitting region includes a pattern of at least two materials having different refractive indexes. The pattern is shaped to demultiplex the TE and TM optical signals by directing a first power majority of the TE optical signal received at the input port to the second output port via asymmetrical power splitting while directing a second power majority of the TM optical signal received at the input port to the first output port via multipath interferometry.

Structures for a power splitter that include a multimode interference coupler and methods of forming such structures. The structure comprises a multimode interference coupler including a grating having a plurality of grating lines, an input waveguide core, and an output waveguide core. The grating lines are disposed between the input waveguide core and the output waveguide core. The structure further comprises a resistive heating element adjacent to the grating lines.

An optical device includes an optical reflector based on a coupled-loopback optical waveguide. In particular, an input port, an output port and an optical loop in arms of the optical reflector are optically coupled to a directional coupler. The directional coupler evanescently couples an optical signal between the arms. For example, the directional coupler may include: a multimode interference coupler and/or a Mach-Zehnder Interferometer (MZI). Moreover, destructive interference during the evanescent coupling determines the reflection and transmission power coefficients of the optical reflector.

In some implementations, an electro-optical device includes a multi-mode interferometer (MMI) variable optical attenuator (VOA), comprising: an input to receive an optical beam; an output to output the optical beam; and an optical waveguide to couple the input to the output, wherein the optical waveguide is configured to self-image the optical beam within the optical waveguide; and a control component to apply a forward voltage across the MMI VOA to control attenuation of the MMI VOA.

Disclosed are an optical modulator and control method therefor, the optical modulator includes an input waveguide, an adjustable ring-shaped resonant cavity, a feedback loop waveguide, a first mode converter, and an output waveguide. The input waveguide is configured to receive an initial optical signal, the adjustable ring-shaped resonant cavity is configured to perform resonance and modulation processing on the initial optical signal and output a first optical signal, the feedback loop waveguide is configured to receive and transmit the first optical signal, the first mode converter is configured to perform mode conversion processing on the first optical signal and output a second optical signal to the adjustable ring-shaped resonant cavity, the adjustable ring-shaped resonant cavity is further configured to perform resonance and modulation processing on the second optical signal and output a third optical signal, and the output waveguide configured to receive and output the third optical signal.

A polarization beam splitter includes an input port, first and second output ports, and a polarization splitting region coupled between the input port and the first and second output ports. The input port is adapted to receive guided optical signals that are polarization multiplexed, including a transverse electric (TE) optical signal and a transverse magnetic (TM) optical signal. The polarization splitting region includes a pattern of at least two materials having different refractive indexes. The pattern is shaped to demultiplex the TE and TM optical signals by directing a first power majority of the TE optical signal received at the input port to the second output port via asymmetrical power splitting while directing a second power majority of the TM optical signal received at the input port to the first output port via multipath interferometry.

An optical phased array chip includes: a light-emitting unit, configured to generate an optical emission signal; a beam-splitting unit, connected to the light-emitting unit, and configured to transmit the optical emission signal to an optical antenna unit and receive and transmit a diffusely reflected optical return signal to a photodetector unit; the optical antenna unit, connected to the beam-splitting unit, configured to transmit the optical emission signal, and configured to receive and transmit the diffusely reflected optical return signal to the beam-splitting unit; the photodetector unit, connected to the beam-splitting unit, and configured to receive and transmit the diffusely reflected optical return signal to a signal processing unit; and the signal processing unit, connected to the photodetector unit, and configured to receive the diffusely reflected optical return signal in an electric current signal manner converted by the photodetector unit and generate a sensing information.

The present disclosure describes photodetectors with multiple inputs and methods of operating photodetectors with multiple inputs. An apparatus includes a substrate, an optical absorber, an optical device, and a tuner. The optical absorber is positioned on the substrate. The optical device produces a first optical signal and a second optical signal from an optical signal received at a first port of the optical device and directs the first optical signal and the second optical signal to the optical absorber. The tuner adjusts a first phase of the first optical signal and a second phase of the second optical signal such that a reflection of the first optical signal from the optical absorber destructively interferes with a reflection of the second optical signal from the optical absorber at the first port.