A receiver assembly (100) and data communications method are disclosed. In one arrangement, a receiver assembly (100) comprises a concentration stage (14). The concentration stage (14) receives radiation via an input surface (120) and outputs concentrated radiation via an output surface (122). The concentration stage comprises a wavelength converting member (6) that converts radiation to longer wavelength radiation. An optical element (102) is provided which is such that if a plane wave of radiation is incident on the optical element a spatial distribution of radiation derived from the plane wave on the input surface of the concentration stage varies as a function of a direction of incidence of the plane wave relative to the optical element. A plurality of detectors (42) are provided, each detecting radiation output from a different portion of the output surface of the concentration stage.

An optical communication method is an optical communication method for performing optical communication with a light-emitting device serving as a communication target. The optical communication method includes: a first step of reading information relating to a distance to the light-emitting device and information relating to a size of a light-emitting region included in the light-emitting device, the information relating to the distance and the information relating to the size being stored in advance; a second step of controlling an imaging range of a camera based on the information relating to the distance and the information relating to the size, the camera capturing an image of light from the light-emitting device; and a third step of extracting a signal from light emitted from the light-emitting device based on image data that the camera has captured in the imaging range.

Disclosed is a transmitter for an optical free-beam communication system, in particular for a data uplink to a satellite, for emission of a light signal, including a number of m data channels. In some non-limiting embodiments or aspects, the data channels may each have a different wavelength WL. Further, a multiplexer is provided for superimposition of the m data channels into a sum signal. A number of n pulse devices form a pulse signal from the sum signal, the pulse signals being chronologically offset from each other. A respective transmission device is connected with a pulse device for emitting the respective pulse signal.

Optical receivers and methods for balanced signal detection using an optical resonator. An example of an optical receiver includes a polarizing beamsplitter that receives a free-space optical signal, a first detector positioned to receive the free-space optical signal with the first polarization, an alignment system configured to rotate either the optical receiver about the optical axis or a polarization of the free-space optical signal, a faraday rotator configured to rotate the polarization of the free-space optical signal, an optical resonator that receives the free-space optical signal from the faraday rotator and accumulates resonant optical signal energy, the optical resonator configured to transmit first output optical signal energy and reject second output optical signal energy, the optical resonator being configured to convert a modulation of the free-space optical signal into an intensity modulation of the first and second output optical signal energies, a second detector that receives the first output optical signal energy and detects the intensity modulation of the first output optical signal energy, and a third detector that receives the second output optical signal energy.

The present invention is directed to a communication signal tracking system comprising an optical receiver including one or more delay line interferometers (DLIs) configured to demultiplex incoming optical signals and a transimpedance amplifier configured to convert the incoming optical signals to incoming electrical signals. The communication signal tracking system further includes a control module configured to calculate a bit-error-rate (BER) of the incoming electrical signals before forward-error correction decoding, and use the BER as a parameter for optimizing settings of the one or more DLIs in one or more iterations in a control loop and generating a back-channel data.

Embodiments herein may relate to an optoelectronic receiver that includes a photonic integrated circuit (PIC) coupled with a light source. Respective PIC sections of the PIC may include a photodiode and a junction capacitor. The optoelectronic receiver may further include an electronic integrated circuit (EIC) coupled with the PIC. Respective EIC sections of the EIC may be communicatively coupled to respective ones of the PIC sections. Other embodiments may be described and/or claimed.

Optical receivers configured to demodulate phase modulated optical signals. In one example, an optical signal receiver includes an optical resonator configured to receive an arriving optical signal and to emit an output optical signal in response to receiving the arriving optical signal, the optical resonator being further configured to transform phase transitions corresponding to phase modulation of the arriving optical into intensity modulation of the output optical signal, an opto-electrical converter configured to convert the output optical signal into an electrical signal, a pulse detector configured to detect pulses in the electrical energy indicative of the phase transitions in the arriving optical signal, and a memory configured to record timing information associated with the pulses detected by the pulse detector.

The present invention is directed to a communication signal tracking system comprising an optical receiver including one or more delay line interferometers (DLIs) configured to demultiplex incoming optical signals and a transimpedance amplifier configured to convert the incoming optical signals to incoming electrical signals. The communication signal tracking system further includes a control module configured to calculate a bit-error-rate (BER) of the incoming electrical signals before forward-error correction decoding, and use the BER as a parameter for optimizing settings of the one or more DLIs in one or more iterations in a control loop and generating a back-channel data.

Disclosed is a self-coherent receiver based on polarization-independent delay interferometers, relating to a technical field of optical communication, including a first beam splitter, a first circulator, a second circulator, a first polarization-independent delay interferometer, a second polarization-independent delay interferometer, a first balanced detector, a second balanced detector and an electrical signal processing module.

Aspects are generally directed to free-space transmitters, free-space receivers, and free-space communication methods. In one example, a free-space communication method includes acts of mapping a data payload to one or more symbols based on a symbol set defined by a digital modulation scheme, varying one or more properties of a signal waveform to phase modulate the signal waveform with the data payload, the one or more symbols each having a symbol duration that defines a timing structure of the modulated signal waveform, and fragmenting the timing structure of the modulated signal waveform to conceal one or more waveform properties of the modulated signal waveform.