In example implementations, an apparatus includes a bus waveguide, a plurality of optical gates coupled to the bus waveguide and an injection coupler. The bus waveguide receives a plurality of constraint signals. Each optical gate outputs an internal state via a local phase shift when at least one of the plurality of constraint signals has a wavelength that matches a respective resonant wavelength. The injection coupler combines the at least one of the plurality of constraint signals with additional constraint signals that are injected. An error is detected in a bit of a message when an overall phase shift has occurred to the at least one of the plurality of constraint signals causing a power level to exceed a power level threshold of an optical gate when the at least one of the plurality of constraint signals constructively interferes with the additional constraint signals that are injected.

Aspects are generally directed to optical signal receivers and methods. In one example, a receiver includes a pump assembly configured to produce an encoded pump signal. The receiver includes an optical resonator positioned to receive an optical signal and the encoded pump signal, the optical resonator including an optical medium to accumulate resonant optical signal energy based on the optical signal, and the optical resonator being configured to emit output optical signal energy and disturb the output optical signal energy in response to a variation in the optical signal, the optical medium being further configured to modify a waveform shape of the output optical signal energy based on the encoded pump signal. The receiver further includes a detector to detect the output optical signal energy and determine a characteristic of the variation in the optical signal based on the waveform shape of the output optical signal energy.

A system, comprising an optical transmitter configured to modulate a pulsed laser signal based on a plurality of data signals to form a plurality of modulated optical data signals, optical time division multiplex the plurality of modulated optical data signals to obtain a multiplexed optical data signal, and transmit the multiplexed optical data signal together with an optical clock signal derived from the pulsed laser signal; and an optical receiver that includes a clock recovery branch configured to recover the optical clock signal into a plurality of phase-shifted recovered optical clock signals and a data branch with a plurality of saturable absorbers (SA), each SA being in optical communication with one of the phase-shifted recovered optical clock signals and configured to receive the multiplexed optical data signal and to transmit of one of the plurality of modulated optical data signals according to the recovered optical clock signal.

Optical signal receivers and methods are provided that include an optical resonator that allows optical signal energy to enter and accumulate inside the optical resonator. A portion of optical signal energy is emitted from the optical resonator at an output, such that the emitted optical signal energy is disturbed when a transition occurs in the received optical signal energy. A detector aligned with the output detects the emitted optical signal energy and is configured to detect the disturbance to the emitted optical signal energy and determine a characteristic of the transition in the received optical signal energy based upon the disturbance.

A radio frequency (RF) photonic spectrometer may include a laser and a receiver branch including an optical modulator optically coupled to the laser and configured to modulate laser light based upon a radio frequency (RF) input signal, and an optical bandpass filter optically coupled to the optical modulator. The spectrometer may further include optical comb branches optically coupled to the laser and each including a frequency comb generator coupled to a respective RF reference signal, with the RF reference signals having different frequencies associated therewith. Furthermore, an output stage may be configured to determine a frequency of the RF input signal based upon outputs of the receiver branch and the optical comb branches.

In example implementations, an apparatus includes a bus waveguide, a plurality of optical gates coupled to the bus waveguide and an injection coupler. The bus waveguide receives a plurality of constraint signals. Each optical gate outputs an internal state via a local phase shift when at least one of the plurality of constraint signals has a wavelength that matches a respective resonant wavelength. The injection coupler combines the at least one of the plurality of constraint signals with additional constraint signals that are injected. An error is detected in a bit of a message when an overall phase shift has occurred to the at least one of the plurality of constraint signals causing a power level to exceed a power level threshold of an optical gate when the at least one of the plurality of constraint signals constructively interferes with the additional constraint signals that are injected.

The present invention discloses an optical switching apparatus, an optical cross-connect node, and an optical signal switching method. The optical switching apparatus includes: N input ports, N OAM modulators in a one-to-one correspondence with the N input ports, an OAM splitter, and M output ports, where the M output ports are in a one-to-one correspondence with M OAM modes; a first input port of the input ports is configured to input a first optical signal, a target output port of the first optical signal is a first output port; a first OAM modulator corresponding to the first input port modulates the first optical signal into an optical signal of a first OAM mode corresponding to the first output port; the OAM splitter transmits, to the first output port, the first optical signal received from the first OAM modulator; and the first output port outputs the first optical signal.

The receiver 11 for self-homodyne detection comprises a coherent detection system and a direct detection system. The receiver comprises a polarization splitter 13, a first splitter 15, a 90 degree polarization rotor 17, a hybrid detector 19, a first balanced detector 21, and a processor 23.

A system, comprising an optical transmitter configured to modulate a pulsed laser signal based on a plurality of data signals to form a plurality of modulated optical data signals, optical time division multiplex the plurality of modulated optical data signals to obtain a multiplexed optical data signal, and transmit the multiplexed optical data signal together with an optical clock signal derived from the pulsed laser signal; and an optical receiver that includes a clock recovery branch configured to recover the optical clock signal into a plurality of phase-shifted recovered optical clock signals and a data branch with a plurality of saturable absorbers (SA), each SA being in optical communication with one of the phase-shifted recovered optical clock signals and configured to receive the multiplexed optical data signal and to transmit of one of the plurality of modulated optical data signals according to the recovered optical clock signal.

A system for modulating passive optical lighting or natural light for visible light communication (VLC) in a non-enclosed space to obtain precise location information or broadband data transmission. The system includes an optical modulator having a framing structure that is at least substantially transmissive with respect to visible light and that has a modulating layer attached thereon.