An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.

An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.

A self-coherent optical data receiver configured to use direct detection of optical signals that is compatible with full (amplitude/phase) electric-field reconstruction. To enable the latter, the direct-detected optical signal includes CW light whose carrier frequency is spectrally aligned with a roll-off edge of the data-modulated portion of the signal. In an example embodiment, the receiver may employ two digital filters placed upstream and downstream, respectively, of the field-reconstruction circuit. The upstream filter is configurable to at least partially cancel the effects of SSBI caused by the direct detection. The downstream filter can be configured to perform electronic dispersion compensation and/or electronic polarization demultiplexing. In different embodiments, a filter controller may operate to adaptively change the filter coefficients of the upstream filter based on different signals generated within the digital receive chain. For example, the filter controller can use either input or output of the downstream filter for this purpose.

An example imaging system may include a spatial light modulator and a coherent optical receiver. The spatial light modulator may be configured to receive an optical input wave and perform wavefront shaping on the optical input wave to output a shaped wave. The coherent optical receiver may include an optical local oscillator, an optical beam splitter, an optical detector, and processing circuitry. The optical detector may be configured to receive a mixed wave from the optical beam splitter that is based on the mixing of a local oscillator wave with a scattering medium output wave that at least initially comprises a speckle pattern formed by the shaped wave interacting with a scattering medium. The processing circuitry may be configured to perform coherent detection on the mixed wave to extract optical amplitude and phase information, and provide an error signal as feedback to the spatial light modulator for performing iterative wavefront shaping.

Consistent with the present disclosure, a local oscillator is provided in a receiver. The local oscillator laser a first and second mirrors and phase section and heaters are provided adjacent each portion of the laser, such that the temperature and thus the frequency of light output from the local oscillator laser may be tuned. Applying electrical power, such as a current or voltage to the phase section may result in rapid frequency tuning of light output from the local oscillator laser but over a limited frequency range. Temperature changes to the mirror sections, however, may afford frequency tuning over a wider range, but frequency tuning the mirror sections requires more time than that required to tune the phase section. Consistent with the present disclosure, a tuning method and apparatus is provided that optimizes laser tuning by selectively tuning the phase and mirror sections.

A polarization-multiplexed self-homodyne analog coherent (PM-SH-ACD) architecture for optical communication links has a receiver section that polarization un-rotates a signal from a fiber optic cable into first and second polarized optical signals; recovers a polarization of the first and second optical signals based on a received polarization recovery signal that is based on a pilot signal measurement signal; demodulates the first optical signal into optical QPSK data and pilot tone signals; demodulates the second optical signal into an optical modulating laser light; splits the first and second optical signals into optical QPSK quadrature signals; converts the optical QPSK quadrature signals into electrical QPSK quadrature signals; detects a polarization of the pilot tone signal and outputs the pilot signal measurement signal polarization recovery signal based on the detected polarization.

A polarization-multiplexed self-homodyne analog coherent (PM-SH-ACD) architecture for optical communication links has a receiver section that polarization un-rotates a signal from a fiber optic cable into first and second polarized optical signals; recovers a polarization of the first and second optical signals based on a received polarization recovery signal that is based on a pilot signal measurement signal; demodulates the first optical signal into optical QPSK data and pilot tone signals; demodulates the second optical signal into an optical modulating laser light; splits the first and second optical signals into optical QPSK quadrature signals; converts the optical QPSK quadrature signals into electrical QPSK quadrature signals; detects a polarization of the pilot tone signal and outputs the pilot signal measurement signal polarization recovery signal based on the detected polarization.

A communication system may an optical signal generator and a signal path. The generator may generate one or more optical local oscillator (LO) signals and an optical frequency comb. Optical paths and an optical demultiplexer may distribute the optical LO signal(s) and the frequency comb to photodiodes in one or more access points. The photodiodes may be coupled to antenna radiating elements. The optical paths may illuminate each photodiode using a signal pair that includes one of the optical LO signals and one of the carriers from the frequency comb. The photodiodes may convey wireless signals using the antenna radiating elements at frequencies given by the differences in frequency between the signals in the signal pairs. The radiating elements may concurrently convey the wireless signals with different external devices at different frequencies, with different devices at the same frequency, and/or with the same device at the same frequency.

A communication system may an optical signal generator and a signal path. The generator may generate one or more optical local oscillator (LO) signals and an optical frequency comb. Optical paths and an optical demultiplexer may distribute the optical LO signal(s) and the frequency comb to photodiodes in one or more access points. The photodiodes may be coupled to antenna radiating elements. The optical paths may illuminate each photodiode using a signal pair that includes one of the optical LO signals and one of the carriers from the frequency comb. The photodiodes may convey wireless signals using the antenna radiating elements at frequencies given by the differences in frequency between the signals in the signal pairs. The radiating elements may concurrently convey the wireless signals with different external devices at different frequencies, with different devices at the same frequency, and/or with the same device at the same frequency.

A device for generating wide capture range frequency tunable optical millimeter-wave signal includes a millimeter-wave signal generating structure, a millimeter-wave signal modulation structure, an optical delay phase detection structure and a feedback control loop. The millimeter-wave signal generating structure obtains millimeter-wave signal by beat frequency of the optical signal generated by a master laser and a slave laser, the millimeter-wave signal is modulated onto an optical carrier of the master laser by the electro-optical modulation structure, and then passes through the optical delay phase detection structure to generate an error signal associated with a frequency of the millimeter-wave signal. The error signal is controlled by the feedback control loop to change temperature and driving current of the slave laser, and adjust a difference between output wavelengths of the master laser and the slave laser, and at last maintain the frequency and phase of the millimeter-wave be stable.