A wavelength division multiplexing filter comprises: a first multi-order Mach-Zehnder interferometer comprising a plurality of first-order Mach-Zehnder interferometers, and a second multi-order Mach-Zehnder interferometer comprising a plurality of first-order Mach-Zehnder interferometers; wherein the first multi-order Mach-Zehnder interferometer and the second multi-order Mach-Zehnder interferometer are included in a group of multiple multi-order Mach-Zehnder interferometers arranged within a binary tree arrangement, the binary tree arrangement comprising: a first set of a plurality of multi-order Mach-Zehnder interferometers, the first set including the first multi-order Mach-Zehnder interferometer, and having an associated spectral response with a first spacing between adjacent passbands, and a second set of at least twice as many multi-order Mach-Zehnder interferometers as in the first set, the second set including the second multi-order Mach-Zehnder interferometer, and having an associated spectral response with a second spacing between adjacent passbands that is twice the first spacing.

An optical signal receiver includes a multimode waveguide for receiving a complex modulated optical signal, an optical resonator that receives the complex modulated optical signal from the multimode waveguide and converts the complex modulated optical signal to an intensity modulated signal, and a detector that is configured to convert the intensity modulated signal into an electrical signal, the electrical signal having an amplitude indicative of an intensity of the intensity modulated signal from the optical resonator, and that provides a detected signal.

An optical signal receiver includes a multimode waveguide for receiving a complex modulated optical signal, an optical resonator that receives the complex modulated optical signal from the multimode waveguide and converts the complex modulated optical signal to an intensity modulated signal, and a detector that is configured to convert the intensity modulated signal into an electrical signal, the electrical signal having an amplitude indicative of an intensity of the intensity modulated signal from the optical resonator, and that provides a detected signal.

Embodiments of the disclosure pertain to an optical transmitter and/or receiver comprising an electrical signal generator configured to generate an electrical signal that is unshielded or unshieldable at a predetermined frequency, a filter downstream from the electrical signal generator configured to reduce an amplitude of electromagnetic interference (EMI) at the predetermined frequency below a predetermined maximum value, an interface through which the EMI can pass in the absence of the filter, and an optical component configured to receive the electrical signal or provide an input signal to the electrical signal generator. A method of reducing EMI in an optical transmitter and/or receiver using the electrical signal generator, the filter and the optical component is also disclosed.

A system and method are provided for simulating circuits that transmit bidirectional signals between some ports using simulators designed originally for electrical circuits and systems, that eliminate the need for different port interfaces. The system and method can be applied to simulate photonic circuits either standalone or integrated with electrical circuits and systems. In one method implemented by the system potential and flow representations, available for example in Verilog-A simulators, are used to create bidirectional signals on a single bus line to transmit optical signals. In another method implemented by the system, the system auto-configures each optical port type as left or right at runtime or during a pre-simulation initialization to allow for bidirectional signals with a single port interface.

A system and method are provided for simulating circuits that transmit bidirectional signals between some ports using simulators designed originally for electrical circuits and systems, that eliminate the need for different port interfaces. The system and method can be applied to simulate photonic circuits either standalone or integrated with electrical circuits and systems. In one method implemented by the system potential and flow representations, available for example in Verilog-A simulators, are used to create bidirectional signals on a single bus line to transmit optical signals. In another method implemented by the system, the system auto-configures each optical port type as left or right at runtime or during a pre-simulation initialization to allow for bidirectional signals with a single port interface.

A receiving device (12) for receiving an optical communication signal, wherein the optical communication signal comprises an encoded or modulated signal, the device comprising: one or more photodetectors (12) configured to produce photodetector signals in response to detecting photons; one or more further photodetectors (14) configured to produce further photodetector signals; a controller (16) configured to select an operational mode of the receiving device in dependence on at least a light level, wherein the operational mode is one of at least a first mode in which a demodulation or decoding process is performed on the photodetector signals and a second mode in which the demodulation or decoding process is performed on the further photodetector signals, and a photon count limiter (18) associated with the one or more photodetector for controlled limiting of the photon count of the one or more photodetectors in dependence on at least a light level.

A receiving device (12) for receiving an optical communication signal, wherein the optical communication signal comprises an encoded or modulated signal, the device comprising: one or more photodetectors (12) configured to produce photodetector signals in response to detecting photons; one or more further photodetectors (14) configured to produce further photodetector signals; a controller (16) configured to select an operational mode of the receiving device in dependence on at least a light level, wherein the operational mode is one of at least a first mode in which a demodulation or decoding process is performed on the photodetector signals and a second mode in which the demodulation or decoding process is performed on the further photodetector signals, and a photon count limiter (18) associated with the one or more photodetector for controlled limiting of the photon count of the one or more photodetectors in dependence on at least a light level.

A forward optical intensity modulation signal, generated by optical intensity-modulating a laser signal using a forward microwave phase modulation signal, is transmitted from a base to a remote station. A backward microwave phase modulation signal, in which frequency of the forward microwave phase modulation signal is changed by demodulating the forward optical intensity modulation signal, is generated, and a backward optical intensity modulation signal, generated by optical intensity-modulating the laser signal using the backward microwave phase modulation signal, is transmitted from the remote station to the base. The backward microwave phase modulation signal is extracted by photoelectric converting the backward optical intensity modulation signal, a round trip timing is extracted by demodulating the backward microwave phase modulation signal, and transmission delay is determined from a difference between the timing and the round trip timing.

Disclosed herein are methods, devices, and system for beam forming and beam steering within ultra-wideband, wireless optical communication devices and systems. According to one embodiment, a free space optical (FSO) communication apparatus is disclosed. The FSO communication apparatus includes an array of optical sources wherein each optical source of the array of optical sources is individually controllable and each optical source configured to have a transient response time of less than 500 picoseconds (ps).