Adaptive communications focal plane arrays that may be implemented in, e.g., a specially-configured camera that can be utilized to receive and/or process information in the form of optical beams are presented. A specialized focal plane array (FPA) having a plurality of optical detectors is utilized, where one or more optical detectors are suppressed such that data is not allowed to be output from the one or more suppressed optical detectors, and only a significantly smaller number or subset of optical detectors receiving optical beams are allowed to output data. In this way, the rate at which data is to be output by an adaptive communications FPA (ACFPA) can be significantly reduced.

The invention relates to a bidirectional wireless communication device which is based on the use of light, including emitting modules, each emitting amplitude- and/or phase-modulated light; and a receiving module made up of: a photodetector illuminated by said modulated light and generating a modulated electrical signal in response to said modulated light; and a processing module for processing the signal generated by said photodetector. The receiving module includes an electronic means positioned between the photodetector and the signal-processing module and capable of matching the impedance of the photodetector to maximise the signal-to-noise ratio of the electrical signal by minimising distortions of said electronic signal associated with incorrect impedance matching at the output of the photodetector, while maximising the level of the modulated electrical signal and the throughput of transmitted data.

A photodetecting device includes a substrate, an array of sub-pixels, and a lens array covering the array of sub-pixels. Each sub-pixel includes a photosensitive layer supported by the substrate, the photosensitive layer being configured to absorb photons and generate photo-carriers, a first doped portion formed in the photosensitive layer of the respective sub-pixel, wherein the first doped portion includes dopants with a first conductivity type,; and a second doped portion formed in the substrate, wherein the second doped portion includes dopants with a second conductivity type different from the first conductivity type. The array further includes an isolation region separating two or more sub-pixels of the array, a routing layer formed on the substrate configured to electrically couple a circuit to multiple sub-pixels of the array. The lens array includes a spacer portion and a plurality of lenses arranged in a one-to-one correspondence with each of the sub-pixels.

Methods and systems for integrated multi-port waveguide photodetectors are disclosed and may include an optical receiver on a chip, where the optical receiver comprises a multi-port waveguide photodetector having three or more input ports. The optical receiver may be operable to receive optical signals via one or more grating couplers, couple optical signals to the photodetector via optical waveguides in the chip, and generate an output electrical signal based on the coupled optical signals using the photodetector. The photodetector may include four ports coupled to two PSGCs. The optical signals may be coupled to the photodetector via S-bends and/or tapers at ends of the optical waveguides. A width of the photodetector on sides that are coupled to the optical waveguides may be wider than a width of the optical waveguides coupled to the sides. Optical signals may be mixed with local oscillator signals using the multi-port waveguide photodetector.

There may be provided detection circuit that may include (i) a photodiode that may be configured to convert radiation to a photodiode electrical signal; (ii) a photodiode bias circuit that may be configured to bias the photodiode, wherein the photodiode bias circuit may include a photodiode bias voltage supply and a photodiode bias capacitor; and (iii) a differential transimpedance amplifier that may be configured to amplify the photodiode electrical signal to provide a differential voltage. The differential transimpedance amplifier may include an amplification circuit and an additional circuit, wherein the amplification circuit may include a positive input port, a negative input port, a positive output port, a negative output port and a common mode input port. The photodiode bias voltage supply may be a floating voltage supply.

A data carrier 2 is provided with a comparator 41, a capacitor 42, a comparator operation adjustment resistor 43, a resistance voltage divider circuit 44 and a reactive-current resistor 45. The capacitor 42 is disposed between the cathode of a photo-diode (PD) 21 and the minus input terminal of the comparator 41. The comparator operation adjustment resistor 43 is disposed between the plus terminal of a primary battery 271 and the minus input terminal of the comparator 41. The resistance voltage divider circuit 44 is constituted by a series connection of voltage dividing resistors 441 and 442. One end of the resistance voltage divider circuit 44 is connected to the plus terminal of the primary battery 271. The junction between the voltage division resistor 441 and the other voltage division resistor 442 is connected to the plus input terminal of the comparator 41.

According to an example aspect of the present invention, there is provided an apparatus (201) comprising adjustable optical equipment (290), a position sensitive photodetector (280), at least one light emitter (220), and control circuitry (104) configured to cause the light emitter (220) and the adjustable optical equipment (290) to output from the apparatus (201) a divergent beam of light, to determine a location of a light signal on the position sensitive photodetector (280) and to cause at least one of the at least one light emitter (220) and the adjustable optical equipment (290) to output from the apparatus (201) a collimated beam of light to a direction selected based at least in part on the location of the light signal on the position sensitive photodetector (280).

An apparatus and method for measuring frequency response characteristics of an optical transmitter and an optical receiver where the apparatus includes: a generating unit configured to generate a driving signal for driving the modulator of the optical transmitter, which comprises at least two frequencies; and a calculating unit configured to respectively calculate the frequency response characteristics of the optical transmitter and the optical receiver according to output signal components in output signals of the optical receiver corresponding to at least two detection signal components of identical amplitudes and different frequencies in detection signals. The frequency response characteristics of the optical transmitter and the optical receiver may be obtained, the amplitude responses and phase responses in the frequency response characteristics may be respectively obtained, and the measurement results are accurate and reliable.

A transmission system for transmitting data as part of a communications system, the data comprising a plurality of data symbols or elements, the transmission system being configured to divide the data into at least a first data portion and a second data portion, wherein the first data portion is communicated by transmitting signals in selected carrier channels, wherein the transmission system is configured to encode at least one data symbol or element by selecting a relative order of at least one first carrier channel having a first operational state and at least one second carrier channel having a second operational state.

Apparatuses including integrated circuit (IC) optical assemblies and processes for operation of IC optical assemblies are disclosed herein. In some embodiments, the IC optical assemblies include a transmitter component to provide light output having a particular beam direction, and a transmitter driver component. The transmitter component includes a light source optically coupled to a plurality of waveguides, a plurality of gratings, and a plurality of phase tuners. The transmitter driver component causes a light provided by the light source to be centered at a particular wavelength and a particular phase to be induced by each phase tuner of the plurality of phase tuners on a respective waveguide of the plurality of waveguides, in accordance with a feedback signal, to generate the light output having the particular beam direction.