A technology is described for a Photonic Integrated Circuit (PIC) radio frequency (RF) in-phase quadrature phase (I/Q) correlator. The PIC RF Correlator can comprise two optical waveguides to receive first and second optical signals that are modulated by first and second RF signals, respectively. Two 1 to M optical splitters can split the first and second RF modulated optical signals. Optical delay lines can delay the M split first RF modulated optical signals. M optical balanced couplers can receive and combine the M first delayed RF modulated optical signals with the M split second RF modulated optical signals. Balanced photodetectors can output a differential integration on the first and second combined RF modulated optical signals for in-phase and quadrature phase signals. A processor can add the outputs of the M optical balanced photodetectors to form a frequency domain correlated signal of the first and second RF signals with real and imaginary parts.

A technology is described for a Photonic Integrated Circuit (PIC) radio frequency (RF) correlator. The PIC RF Correlator can comprise two optical waveguides to receive first and second optical signals that are modulated by first and second RF signals, respectively. Two 1 to M optical splitters can split the first and second RF modulated optical signals. Optical delay lines can delay the M split first RF modulated optical signals. M optical balanced couplers can receive and combine the M first delayed RF modulated optical signals with the M split second RF modulated optical signals. Balanced photodetectors can output a differential integration on the first and second combined RF modulated optical signals. A processor can add the outputs of the M optical balanced photodetectors to form a frequency domain correlated signal of the first and second RF signals.

A technology is described for a Photonic Integrated Circuit (PIC) radio frequency (RF) correlator. The PIC RF Correlator can comprise two optical waveguides to receive first and second optical signals that are modulated by first and second RF signals, respectively. Two 1 to M optical splitters can split the first and second RF modulated optical signals. Optical delay lines can delay the M split first RF modulated optical signals. M optical balanced couplers can receive and combine the M first delayed RF modulated optical signals with the M split second RF modulated optical signals. Balanced photodetectors can output a differential integration on the first and second combined RF modulated optical signals. A processor can add the outputs of the M optical balanced photodetectors to form a frequency domain correlated signal of the first and second RF signals.

Various example embodiments relate to an apparatus and method for nonlinear equalization based on an absolute operation, and may be configured to generate coefficients and compensate for nonlinear distortions by using an absolute operation for an input signal based the coefficients.

An optical communication device includes an excitation light source that outputs excitation light, a multiplexer that multiplexes signal light and the excitation light outputted from the excitation light source, a first nonlinear optical medium into which the multiplexed excitation light and the signal light are inputted, and a second nonlinear optical medium that is coupled to the first nonlinear optical medium in series and has an optical property different from that of the first nonlinear optical medium.

A method and apparatus for transporting data through a single optical fiber (SOF) the method comprising the steps of providing (S1) transmission Tx, wavelength division multiplexed, WDM, data channels and reception Rx, wavelength division multiplexed, WDM, data channels having the same frequency grid with frequency gaps between the WDM data channels; frequency shifting (S2) the Tx-WDM data channels and/or the Rx-WDM data channels to avoid spectral overlap between the Tx-WDM data channels and the Rx-WDM data channels; combining (S3) the frequency shifted Tx-WDM data channels and the frequency shifted Rx-WDM data channels; and transporting (S4) data via the combined WDM data channels through said single optical fiber (SOF) in opposite directions.

A method and apparatus for transporting data through a single optical fiber (SOF) the method comprising the steps of providing (S1) transmission Tx, wavelength division multiplexed, WDM, data channels and reception Rx, wavelength division multiplexed, WDM, data channels having the same frequency grid with frequency gaps between the WDM data channels; frequency shifting (S2) the Tx-WDM data channels and/or the Rx-WDM data channels to avoid spectral overlap between the Tx-WDM data channels and the Rx-WDM data channels; combining (S3) the frequency shifted Tx-WDM data channels and the frequency shifted Rx-WDM data channels; and transporting (S4) data via the combined WDM data channels through said single optical fiber (SOF) in opposite directions.

An optical transmitter includes a plurality of light-emitting units each configured to transmit an optical signal having a different wavelength and change the wavelength of the optical signal. At least one light-emitting unit of the plurality of light-emitting units is configured to adjust the wavelength.

An optical transmitter includes a plurality of light-emitting units each configured to transmit an optical signal having a different wavelength and change the wavelength of the optical signal. At least one light-emitting unit of the plurality of light-emitting units is configured to adjust the wavelength.

A technology is described for a Photonic Integrated Circuit (PIC) radio frequency (RF) correlator. The PIC RF Correlator can comprise two optical waveguides to receive first and second optical signals that are modulated by first and second RF signals, respectively. Two 1 to M optical splitters can split the first and second RF modulated optical signals. Optical delay lines can delay the M split first RF modulated optical signals. M optical balanced couplers can receive and combine the M first delayed RF modulated optical signals with the M split second RF modulated optical signals. Balanced photodetectors can output a differential integration on the first and second combined RF modulated optical signals. A processor can add the outputs of the M optical balanced photodetectors to form a frequency domain correlated signal of the first and second RF signals.