An optical receiver may include a planar lightwave circuit with an optical path and a tapered reflection surface to direct an optical beam toward a top surface of the planar lightwave circuit. The optical receiver may include a photodiode disposed onto the top surface of the planar lightwave circuit such that a receive portion of the photodiode is aligned to the optical path, wherein a gap between the photodiode and the planar lightwave circuit is less than 5 microns.

A portable transponder device including a receiver having an input frequency range of either but not both of 20 kHz-300 kHz and 3 MHz-30 MHz, the receiver having a plurality of signal input channels, the input frequency range not including an infra-red frequency range, and infra-red frequency range receiving circuitry receiving infra-red frequency range signals modulated by at least one signal in the input frequency range, and providing the infra-red frequency range signals to the receiver through at least one signal input channel of the plurality of signal input channels.

An optical detector for converting an optical signal into an electrical signal comprises a photo sensitive device adapted for receiving the optical signal and converting it into an electrical signal. The optical detector moreover comprises a bias compensation circuit and a control circuit. The control circuit is adapted to control the bias compensation circuit to maintain a bias level across the photo sensitive device above a minimum bias level, and to turn the bias compensation circuit off when a current through the photo sensitive device is so small that the bias level across the photo sensitive device is above the minimum bias level.

High-performance ultra-wideband Phased Array Sensors (PAS) are disclosed, which have unique capabilities, enabled through photonic integrated circuits and novel optical architectures. Unique capabilities for a Receive PAS are provided by wafer scale photonic integration including heterogeneous integration of III-V materials and ultra-low-loss silicon nitride waveguides, combining key component technologies into complex PIC devices. Novel aspects include optical multiplexing combining wavelength division multiplexing and/or a novel extension to array photodetectors providing the capability to combine many RF photonic signals with very low loss. The architecture also includes optical down-conversion, as well as digital signal processing to improve the linearity of the system. Simultaneous multi-channel beamforming is achieved through optical power splitting of optical signals to create multiple exact replicas of the signals that are then processed independently.

An integrated photonics monopulse comparator includes an array of squinted monopulse elements, each monopulse element producing an RF signal in response to a received inbound signal and each RF signal having a squinted RF voltage. The comparator includes a laser source for producing a wavelength division multiplexed (WDM) optical signal comprising multiple components having discrete wavelengths. The component signals may be multiplexed and demultiplexed and routed through cascading optical phase modulators, each phase modulator connected to a monopulse element and capable of modulating a component signal according to the voltages of the RF signals produced by the corresponding monopulse element. The resulting modulated component optical signals undergo coherent photodetection by arrays of paired photodiodes, each pair receiving component signals of like wavelength. The output signals of each array are proportional in voltage to sums and differences from which arrival angles of the inbound signal may be calculated.

The present invention provides an optical transmitter including a semiconductor laser and a control method thereof for preventing crosstalk between channels in an NG-PON2 with a 100 GHz channel spacing by reducing a wavelength drift of the semiconductor laser. The wavelength drift occurs between a few nanoseconds and a few hundreds nanoseconds from the beginning of a burst when the semiconductor laser is operated in a burst-mode.

An apparatus comprises a laser emitter configured to transmit laser energy across an air gap to a separate device, and a driver circuit electrically coupled to the laser emitter and to an electrical interface. The driver circuit is configured to detect voltage levels at the electrical interface including a first voltage level, a second voltage level, and a third voltage level, and drive the laser emitter at a first power level when detecting the first voltage level, drive the laser emitter at a second power level when detecting the second voltage level, and drive the laser emitter at a third power level intermediate the first and second power levels when detecting the third voltage level.

The present disclosure provides an optical module comprising: a photoelectric conversion unit, a first demodulation circuit, and a second demodulation circuit; the first demodulation circuit and the second demodulation circuit are respectively connected to the photoelectric conversion unit; the photoelectric conversion unit is configured to convert the received optical signal into an electrical signal; the first demodulation circuit is configured to demodulate an electrical signal converted by the photoelectric conversion unit and generate a high-frequency electrical signal; the second demodulation circuit is configured to demodulate an electrical signal converted by the photoelectric conversion unit and generate a low-frequency electrical signal.

An apparatus comprises a laser emitter configured to transmit laser energy across an air gap to a separate device; a photodiode configured to detect laser energy received across the air gap from the separate device; and logic circuitry configured to initiate recurrent transmission of a laser pulse by the laser emitter; and end the recurrent transmission in response to detecting laser energy received by the photodiode from the separate device.

An optical receiver circuit includes an input terminal receiving current signal from photodetector; a trans-impedance amplifier converting the current signal into voltage signal; an inductor having one end connected to the input terminal and another end connected to the input of the trans-impedance amplifier; a first variable resistor having a first end connected to the other end of the inducer a second end receiving bias voltage, and a third end receiving a control signal, where the first variable resistor varies a resistance between the first end nut the second end in accordance with the control signal; and a second variable resistor having a first end connected to the one end of the inductor, a second end receiving bias voltage, and a third end receiving a control signal, where the second variable resistor varies a resistance between the first end and the second end in accordance with Me control signal.