This application discloses a temperature feedback control apparatus, method. The method includes two electric switches, a feedback control unit and an optical component. A first electric switch is configured to control that only a first channel of at least two channels that correspond to the first electric switch is conducted at a moment, to feed back an optical signal of a target optical component connected to the first channel to the feedback control unit. The feedback control unit is configured to calculate temperature of the corresponding optical component based on an electrical signal converted from the optical signal, to obtain a control signal. The second electric switch is configured to control, when the first channel is conducted, that only the second channel is conducted, to transmit the control signal to the target optical component to adjust its temperature. The optical component connects to both the first and second channels.

In a system for converting digital data into a modulated optical signal, an electrically controllable device, including a modulator having one or more actuating electrodes, provides an analog-modulated optical signal that is modulated in response to output data bits of a digital-to-digital mapping. A digital-to-digital conversion provides the mapping of input data words to the output data bits. The mapping enables adjustments to correct for non-linearities and other undesirable characteristics, thereby improving signal quality.

In a system for converting digital data into a modulated optical signal, an electrically controllable device, including a modulator having one or more actuating electrodes, provides an analog-modulated optical signal that is modulated in response to output data bits of a digital-to-digital mapping. A digital-to-digital conversion provides the mapping of input data words to the output data bits. The mapping enables adjustments to correct for non-linearities and other undesirable characteristics, thereby improving signal quality.

An optical DAC includes a 1:N splitter that splits a single light beam into N light beams corresponding to bits of an N-bit electrical digital signal (where N is an integer of 2 or more) and makes the N light beams different in optical intensities such that (N−1) light beams corresponding to bits except a least significant bit of the N-bit electrical digital signal each have an optical intensity which is four times as large as an optical intensity of a light beam corresponding to a next less significant bit, an optical intensity modulator that individually intensity-modulates the N light beams, an N:1 combiner that combines the N output light beams intensity-modulated by the optical intensity modulator and outputs the combined light, and a phase shifter that is adjustable such that the light beams that are combined by the N:1 combiner are made in phase.

An optical DAC includes a 1:N splitter that splits a single light beam into N light beams corresponding to bits of an N-bit electrical digital signal (where N is an integer of 2 or more) and makes the N light beams different in optical intensities such that (N−1) light beams corresponding to bits except a least significant bit of the N-bit electrical digital signal each have an optical intensity which is four times as large as an optical intensity of a light beam corresponding to a next less significant bit, an optical intensity modulator that individually intensity-modulates the N light beams, an N:1 combiner that combines the N output light beams intensity-modulated by the optical intensity modulator and outputs the combined light, and a phase shifter that is adjustable such that the light beams that are combined by the N:1 combiner are made in phase.

A photonically-sampled electronically-quantized analog-to-digital converter generates an optical signal comprising a series of optical pulses. The optical signal is split into a first and a second optical path. The split optical signal is detected in the first path and then the detected optical signal is converted to a reference digital signal. The split optical signal in the second path is modulated with an input RF signal and a plurality of demultiplexed RF-modulated optically-sampled signals is generated from the modulated optical signal. The plurality of demultiplexed RF-modulated optically-sampled signals is then pulse broadened, detected, and converted to a plurality of sampled-RF digital signals. The reference digital signal and the plurality of sampled-RF digital signals are digital signal processed to generate a digital representation of the input RF signal.

A photonically-sampled electronically-quantized analog-to-digital converter generates an optical signal comprising a series of optical pulses. The optical signal is split into a first and a second optical path. The split optical signal is detected in the first path and then the detected optical signal is converted to a reference digital signal. The split optical signal in the second path is modulated with an input RF signal and a plurality of demultiplexed RF-modulated optically-sampled signals is generated from the modulated optical signal. The plurality of demultiplexed RF-modulated optically-sampled signals is then pulse broadened, detected, and converted to a plurality of sampled-RF digital signals. The reference digital signal and the plurality of sampled-RF digital signals are digital signal processed to generate a digital representation of the input RF signal.

A digital-to-analog converter (DAC) system preferably includes one or more optical modulators and can optionally include one or more electronic DAC arrays. A method for digital-to analog conversion preferably includes receiving digital inputs and providing analog optical outputs. The method for digital-to analog conversion is preferably performed using the DAC system.

An encoding and decoding method for an optical isolation amplifier including an encoder, an optical driver, a light source, an optical detector, and a decoder, and employing sigma-delta modulation technology is provided. The method includes: generating a plurality of first pulses, each having a predetermined pulse width, through the encoder when an input digital signal experiences an input pulse rising or falling edge; outputting an encoded signal having the plurality of first pulses to the optical driver; driving the light source through the optical driver, according to the plurality of first pulses, so as to output an encoded optical signal; generating a detected signal through the optical detector detecting the encoded optical signal, and the detected signal has a plurality of second pulses; and duplicating the input digital signal of the encoder through the decoder, according to the detected signal having the plurality of second pulses.

An optical digital to analog converter (oDAC) that may include (a) multiple optical paths that are parallel to each other; (b) a combiner, (c) a splitter that is configured to receive an optical signal at a splitter input and split the optical signal between multiple splitter outputs to provide multiple path input signals to the multiple optical paths. The multiple optical paths are configured to optically process, in parallel, path input signals to provide path output signals. Each optical path is configured to apply an optical process that comprises applying optical modulation, by an optical gate of the optical path and under a control of an electrical modulator, to provide an optical signal having a value selected out of multiple constellation levels. The combiner is configured to add the multiple path output signals to provide an oDAC output signal having a value selected from values of a single quadrature constellation.