摘要:
An optical heterodyne receiver and a method of extracting data from a phase-modulated input optical signal. In one embodiment, the optical heterodyne receiver includes: (1) a photonic quadrature demodulator having first and second optical inputs and first and second electrical outputs and configured to generate at the first and second electrical outputs an in-phase signal and a quadrature-phase signal, respectively, in response to receiving a modulated optical signal at the first optical input and a reference optical oscillator signal at the second optical input, (2) a passive radio frequency single sideband demodulator coupled to the photonic quadrature demodulator and configured to extract at least one sideband of the in-phase signal or the quadrature-phase signal and (3) at least one analog-to-digital converter coupled to the passive radio frequency single sideband demodulator and configured to receive and sample the at least one sideband.
摘要:
An apparatus and method for use in an adaptive optical equalizer including, in one embodiment an optical equalizer having an input and output coupled to receive an incoming optical signal and configured to generate an output optical signal by phase modulation and/or amplitude modulation of the receive optical signal in response to electronic control signals. A photodiode is configured to receive the output optical signal and generate an representative current signal. A control signal generator is configured to generate the electronic control signals in accordance with predetermined criteria and in response to the representative current signal from the photodiode. An interferometer is connected to receive the incoming and output optical signal from the optical equalizer, the differential amplifier is configured to receive electronic versions of outputs from the interferometer for generating a difference signal and supplying the difference signal to the control signal generator.
摘要:
A method is provided for identifying a contaminant in a gaseous space. The method includes: generating a broadband optical waveform; shaping the optical waveform to match an expected waveform for a known contaminant; and transmitting the shaped optical waveform towards an unknown contaminant. Upon receiving a reflected optical waveform from the unknown contaminant, determining whether the unknown contaminant correlates to the known contaminant based on the reflected waveform.
摘要:
A method for transmitting digital data includes splitting a coherent optical carrier having a subcarrier into mutually coherent optical carriers, producing corresponding sequences of phase shifts in each of the mutually coherent optical carriers, and then, interfering the mutually coherent optical carriers. The interfering produces an output optical carrier whose subcarrier has modulated inphase and quadrature components with a corresponding sequence of pairs of values. The pairs of values of the modulated inphase and quadrature phase components produced by the interfering correspond to a sequence of coordinate pairs for the signal points the 4-PSK 2D, 16-QAM 2D, or 16-PSK 2D constellation.
摘要:
An optical digital-to-analog (D/A) converter and a method of optically converting digital data into analog form. In one embodiment, the optical D/A converter includes: (1) a splitter configured to receive and split an input coherent optical carrier into a plurality of mutually coherent optical carriers, (2) a switching stage coupled to the splitter and including a corresponding plurality of selector switches configured to pass or interrupt selected ones of the plurality of coherent optical carriers responsive to pattern bits, (3) an amplitude and phase offset stage coupled to the switching stage and including a corresponding plurality of amplitude and phase offset units configured to offset amplitudes or phases of passed ones of the plurality of mutually coherent optical carriers responsive to offset signals and (4) a combiner coupled to the amplitude and phase offset stage and configured to recombine the mutually coherent optical carriers to yield an optical output signal.
摘要:
An optical digital-to-analog conversion is realized by employing either a continuous wave or pulsed laser optical signal. The laser optical signal is split into a plurality of mutually coherent optical beams, which are phase shift modulated by bits of a digital data sequence to be converted to an analog signal. The phase shift modulated optical beams are recombined to realize the desired digital-to-analog converted optical signal.
摘要:
A method for transmitting digital data includes splitting a coherent optical carrier having a subcarrier into mutually coherent optical carriers, producing corresponding sequences of phase shifts in each of the mutually coherent optical carriers, and then, interfering the mutually coherent optical carriers. The interfering produces an output optical carrier whose subcarrier has modulated inphase and quadrature components with a corresponding sequence of pairs of values. The pairs of values of the modulated inphase and quadrature phase components produced by the interfering correspond to a sequence of coordinate pairs for the signal points the 4-PSK 2D, 16-QAM 2D, or 16-PSK 2D constellation.
摘要:
An optical digital-to-analog (D/A) converter and a method of optically converting digital data into analog form. In one embodiment, the optical D/A converter includes: (1) a splitter configured to receive and split an input coherent optical carrier into a plurality of mutually coherent optical carriers, (2) a switching stage coupled to the splitter and including a corresponding plurality of selector switches configured to pass or interrupt selected ones of the plurality of coherent optical carriers responsive to pattern bits, (3) an amplitude and phase offset stage coupled to the switching stage and including a corresponding plurality of amplitude and phase offset units configured to offset amplitudes or phases of passed ones of the plurality of mutually coherent optical carriers responsive to offset signals and (4) a combiner coupled to the amplitude and phase offset stage and configured to recombine the mutually coherent optical carriers to yield an optical output signal.
摘要:
The present invention provides an optical beamforming RF transmitter. In one embodiment, the optical beamforming RF transmitter includes an optical WDM splitter having an input and a plurality of outputs. The optical beamforming RF transmitter also includes an array of antennas, where each antenna has an optical input configured to drive the corresponding antenna, and an array of optical modulators, such that each modulator has an output connected to a corresponding one of the antennas and an input connected to one of the outputs of the optical WDM splitter. The optical beamforming RF transmitter further includes a mode-locked laser having an output optically coupled to the input of the optical WDM splitter.
摘要:
A receiver for coherent detection of a PSK modulated optical carrier includes an optical detector, digital-to-analog converters, and a digital module. The optical detector is configured to mix the modulated optical carrier with two phase components of a reference optical carrier and to produce analog output signals representative of optical signals produced by said mixing. The digital-to-analog converters are connected to receive the analog output signals and to produce digital signals from the received analog output signals. The digital module is connected to receive the digital signals and to perform one of compensating the received digital signals for a conjugate phase misalignment between the mixed components, extracting phase of the received digital signals, and estimating a frequency offset between the two carriers from the received digital signals.