An optical transmission module includes a photonic integrated circuit, a processor that controls the power state of the photonic integrated circuit, and a current source circuit that supplies electric current to a light source used for the photonic integrated circuit. The photonic integrated circuit has an optical multiplexer block including a plurality of multiplexers connected in a n-level tree structure (n is an integer greater than 1), 2{circumflex over ( )}n optical modulators connected to inputs of the optical multiplexer block, and a photodetector connected to an input or an output of each of the plurality of the multiplexers. The light source emits a light beam to be incident onto a corresponding one of the 2{circumflex over ( )}n optical multiplexers. The processor controls the current source circuit for each of the plurality of the multiplexers, based on the monitored value acquired from the photodetector provided to each of the plurality of the multiplexers.

A multi-level semiconductor device, the device including: a first level including integrated circuits; a second level including a structure designed to conduct electromagnetic waves, where the second level is disposed above the first level, where the first level includes crystalline silicon; an oxide layer disposed between the first level and the second level; and a plurality of electromagnetic modulators, where the second level is bonded to the oxide layer, and where the bonded includes oxide to oxide bonds.

A photo detector includes a variable optical attenuator provided on a substrate, an optical 90-degree hybrid device provided on the substrate, and a plurality of photodiodes provided on the substrate. The plurality of photodiodes are optically coupled to the variable optical attenuator via the optical 90-degree hybrid device. The variable optical attenuator includes an optical waveguide disposed on the substrate, a heater configured to heat the optical waveguide, and an insulating layer at least partially disposed between the substrate and the optical waveguide.

A fiber-to-fiber system for multi-layer ferroelectric on insulator waveguide devices is described. The system comprises a fiber-to-chip coupler that couples light from a standard optical fiber to multi-layer ferroelectric on insulator waveguides. The multi-layer ferroelectric on insulator waveguides are integrated with electrodes to implement an optical device, an electro-optical device, or a non-linear optical device, such as an electro-optical modulator, with microwave and optical waveguide crossings compatible with packaging. A second fiber-to-chip coupler outputs the light from the multi-layer ferroelectric on insulator device to a standard optical fiber.

A digital measuring device implemented on a photonic integrated circuit, the digital measuring device including a laser source implemented on the photonic integrated circuit configured to provide light, a first waveguide structure implemented on the photonic integrated circuit configured to direct a first portion of light from the laser source at a moving object and receive light reflected from the moving object, a second waveguide structure implemented on the photonic integrated circuit configured to combine a second portion of light from the laser source with the light reflected from the moving object to produce a measurement beam, a first multiplexer implemented on the photonic integrated circuit configured to split the measurement beam into a plurality of channels, and a plurality of detectors implemented on the photonic integrated circuit configured to detect an intensity value of each channel to measure a distance between the digital measuring device and the moving object.

An integrated wavelength division multiplexing (WDM) optical transceiver comprises the following elements: (1) a light source; (2) an array of photodiodes responsive to a plurality of optical signals and forming a plurality of electrical received information signals therefrom; and (3) a photonics integrated module (PIM) including transmission components and receiving components necessary to provide transceiver functionality. The transmission components include a demultiplexer, an electro-optic modulator array, and a multiplexer for combining a plurality of modulated optical signals onto a single output signal path as the transceiver output. The receiving components include a demultiplexer responsive to an incoming WDM signal for separating each wavelength component and creating a plurality of received optical signals.

An optical transceiver may include a circuit board, lasers, and a PLC including optical multiplexers and demultiplexers. The PLC may be coupled to fiber optic lines at a forward edge of the PLC, with a rear edge of the PLC receiving light for transmission generated by the lasers. Light received at the forward edge of the PLC may be demultiplexed into data channels and routed to a top surface of the PLC for optoelectronic conversion by photodetectors. In some embodiments each data channel is routed into a corresponding plurality of waveguides, with each of the corresponding plurality of waveguides providing light to the same photodetector. In some embodiments at least some receive side electronic circuitry, other than photodetectors, is stacked on top of the PLC.

In some implementations, an optical isolator core includes a Faraday rotator and a plurality of birefringent crystal plates. The plurality of birefringent crystal plates may include a first birefringent crystal plate to separate input light into light having a first polarization and light having a second polarization, and a second birefringent crystal plate to combine the light having the first polarization and the light having the second polarization in output light that is laterally displaced by the single stage optical isolator. The Faraday rotator may be provided between the first birefringent crystal plate and the second birefringent crystal plate. In some implementations, the plurality of birefringent crystal plates further include a third birefringent crystal plate provided between the Faraday rotator and the second birefringent crystal plate. Additionally, or alternatively, the optical isolator core may further include a half-wave plate arranged between the Faraday rotator and the first birefringent crystal plate.

An on-chip wavelength locker may include an optical waveguide splitter to split an input optical signal received from a laser. The on-chip wavelength locker may include a plurality of integrated periodic optical elements, each to receive a respective portion of the input optical signal after splitting of the input optical signal by the optical waveguide splitter, and provide, based on the respective portion of the input optical signal, a respective periodic output optical signal of a plurality of periodic output optical signals. Each periodic output optical signal, of the plurality of periodic output optical signals, may be phase shifted with respect to other periodic output optical signals of the plurality of periodic output optical signals. The on-chip wavelength locker may include a plurality of integrated photodiodes to receive the plurality of periodic output optical signals in association with wavelength locking the laser.

A fiber-to-fiber system for multi-layer ferroelectric on insulator waveguide devices is described. The system comprises a fiber-to-chip coupler that couples light from a standard optical fiber to multi-layer ferroelectric on insulator waveguides. The multi-layer ferroelectric on insulator waveguides are integrated with electrodes to implement an optical device, an electro-optical device, or a non-linear optical device, such as an electro-optical modulator, with microwave and optical waveguide crossings compatible with packaging. A second fiber-to-chip coupler outputs the light from the multi-layer ferroelectric on insulator device to a standard optical fiber.