An optical module configured to electrically connect to a host. A linear equalizer performs equalization on a host equalized signal to create a module equalized signal, and a driver configured to present the module equalized signal from the linear equalizer to an optical conversion device at a magnitude suitable for the optical conversion device. An optical conversion device receives the module equalized signal from the driver, converts the module equalized signal to an optical signal, and transmit the optical signal over an optical channel. Also part of the optical module is an interface which communicates supplemental equalizer settings to the host. A memory stores the supplemental equalizer settings which reflect the optical modules effect on a signal passing through the optical module. A controller oversees communication of the supplemental equalizer settings to the host such that the host uses the supplemental equalizer settings to modify host equalizer settings.

A method for making a pair of photodiodes to detect low-power optical signal includes providing a waveguide including one or more branches in a silicon photonics substrate to deliver an input optical signal to the silicon photonics integrated circuit; forming a pair of nearly redundant photodiodes in silicon photonics platform in the silicon photonics substrate. coupling a first one of the pair of nearly redundant photodiodes optically to each of the one or more branches for receiving the input optical signal combined from all of the one or more branches; coupling a second one of the pair of nearly redundant photodiodes electrically in series to the first one of the pair of nearly redundant photodiodes; and drawing a current from the first one of the pair of nearly redundant photodiodes under a reversed bias voltage applied to the pair of nearly redundant photodiodes.

A photonic random signal generator includes an incoherent optical source configured to generate an optical noise signal, a filter configured to generate a filtered optical noise signal using the optical noise signal, a coupler, a photodetector, a filter, and a limiter. The coupler couples the filtered optical noise signal and a delayed version of the filtered optical noise signal to generate a first coupled signal and a second coupled signal. The photodetector generates an output signal representative of a phase difference between the filtered optical noise signal and the delayed version of the filtered optical noise signal using the first coupled signal and the second coupled signal. The filter filters the output signal representative of the phase difference to generate an analog random signal. The limiter thresholds the analog random signal based on a clock signal, to generate a digital random signal.

Dynamic error-quantizer tuning systems and methods prevent misconvergence to local minima by using a dynamic quantizer circuit that controls reference voltages of three or more comparators that are independently adjusted to modify the transfer function of the dynamic quantizer circuit. A weighted sum of the comparator outputs is subtracted from the input to form an error signal in a control loop. The ratio of the reference voltages is chosen to reduce or eliminate local minima during a convergence of the control loop and is set to values that minimize a mean squared error signal with respect to discrete modulation states of the input after the convergence of the control loop is complete.

An example optical receiving device includes a photodiode to receive an optical signal, where the photodiode is configured to conduct a current that is based on an optical power of the optical signal, and a radio frequency (RF) gain circuitry to generate one or more analog electrical signals based on the current and based on gain provided by the RF gain circuitry. A power detector is configured to receive an analog electrical signal of the one or more analog electrical signals, to detect alternating current (AC) power of the optical signal based on the analog electrical signal, and to output a signal representing the AC power based on the detecting.

High-performance ultra-wideband Phased Array Antennas (PAA) are disclosed, having unique capabilities, enabled through photonic integrated circuits and novel optical architectures. Unique capabilities for PAA systems are enabled by photonic integration and ultra-low-loss waveguides. 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. Architectures include tunable optical up-conversion and down-conversion systems, moving a chosen frequency band between baseband and a high RF frequency band with high dynamic range. Simultaneous multi-channel RF beamforming is achieved through power combining/splitting of optical signals.

An optical receiver includes: a pre-amplifier to convert a current signal into a voltage signal; an LIA to amplify and limit an amplitude of the voltage signal; a transmission line connecting the pre-amplifier with the LIA; an AC coupling capacitor inserted in the middle of the transmission line or at an end of the transmission line; a termination circuit connected with the transmission line, for switching to a first resistance or a second resistance higher than the first resistance in response to a switching signal; and an AC load connected with the transmission line. The AC load is open in a low-frequency range of the voltage signal and having a resistance enabling impedance matching with the pre-amplifier and the transmission line in a high-frequency range of the voltage signal, wherein the termination circuit and the AC load are electrically connected in parallel.

The present disclosure discloses a visible light communication apparatus, a lock device, and a visible light communication method. The visible light communication method includes: transmitting, by at least two transmitting devices, visible light carrying respective corresponding information; and sending, by a receiving device, an instruction for correct matching upon determining, according to received superposed visible light, that the superposed visible light meets a preset condition; where the corresponding information includes at least one of a frequency, luminance, and a color of the visible light transmitted by the transmitting devices and a relative position of the transmitting devices to the receiving device. The method can improve security of visible light communication.

This disclosure relates to a signal processing method and apparatus. The method includes: receiving an optical signal in a target receive channel, and converting the optical signal into an electrical signal; determining, in the converted electrical signal, an electrical signal associated with a non-overlapping frequency band between the target receive channel and another channel, where the another channel is a channel that overlaps the target receive channel; and determining, based on the electrical signal associated with the non-overlapping frequency band, an electrical signal corresponding to a valid received optical signal that does not include an interfering optical signal in the target receive channel. In this disclosure, the target transmit channel and the another channel are set to channels that overlap each other, thereby reducing bandwidths occupied by the channels. In the method provided in the embodiments of this disclosure, spectrum utilization can be improved, thereby improving a data transmission rate.

A receiver apparatus comprises circuitry configured for storing a first sequence of values. At the receiver apparatus, a communications signal is received which conveys a second sequence of values, the second sequence of values being related to the first sequence of values. According to some examples, the second sequence of values is identical to the first sequence of values. At the receiver apparatus, P results are calculated from a cross-correlation of the first sequence of values with at least a portion of a representation of the communications signal, where P is a positive integer. According to some examples, P≥2. An estimate of a phase offset of a continuous clock is calculated as a function of the P results. According to some examples, the function is a non-linear function. The estimate of the clock phase offset may be used to achieve clock recovery at the receiver apparatus.