A system and method for applying a time-varying phase shift to an optical signal is described. Such a phase shift results in a frequency shift of the optical signal, which can be useful for instance in sensing applications. The design uses cross phase modulation (XPM) in a nonlinear medium such as optical fiber. The pump producing the XPM experiences a change in energy along the medium, for instance due to loss. The pump and signal have mismatched group velocities such that they walk-off each other in time, and the pump pulse repetition rate is chosen so that it has a specific relationship with respect to the walk-off. The design is compatible with very low signal loss and does not require high fidelity electrical control signals. It is capable of high-efficiency one-directional serrodyne frequency shifts, as well as producing symmetric frequency shifts. It can also be made polarization independent.

An integrated receiver chip comprising: a first end and a second end; at least one optical input port disposed at the first end; a polarization manipulation device optically connected to one of the at least one optical input port, the polarization manipulation device being adapted to split an optical signal into a first and a second optical signals; a first and a second dispersion compensators each optically connected to the polarization manipulation device, the first and the second dispersion compensators each being adapted to selectively induce a dispersion on an optical signal propagating through the dispersion compensator; and a first and a second photodetectors optically connected to the first and the second dispersion compensators, respectively.

A digital receiver is configured to process a polarization multiplexed carrier from a communication network. The polarization multiplexed carrier includes a first polarization and a second polarization. The receiver includes a first lane for transporting a first input signal of the first polarization, a second lane for transporting a second input signal of the second polarization, a dynamic phase noise estimation unit disposed within the first lane and configured to determine a phase noise estimate of the first input signal, a first carrier phase recovery portion configured to remove carrier phase noise from the first polarization based on a combination of the first input signal and a function of the determined phase noise estimate, and a second carrier phase recovery portion configured to remove carrier phase noise from the second polarization based on a combination of the second input signal and the function of the determined phase noise estimate.

Disclosed are a signal transmission and reception method and device in a wireless communication system. A method for receiving a signal by a terminal in a wireless communication system according to an embodiment of the present specification comprises the steps of: receiving configuration relating to a signal which is down-converted in frequency on the basis of an O/E converter; and receiving the signal in a particular resource region on the basis of the configuration. A frequency domain of the particular resource region comprises a plurality of chunks. The chunks comprise at least one component carrier (CC). The configuration comprises information indicating a main chunk relating to differential phase shift keying (DPSK). The transmission of the signal is on the basis of the DPSK applied between the chunks in the frequency domain with respect to the main chunk.

A silicon photonics based temperature-insensitive delay line interferometer (DLI). The DLI includes a first arm comprising a first length of a first material characterized by a first group index corresponding to a first phase delay to transfer a first light wave with a first peak frequency and a second arm comprising a second length of a second material characterized by a second group index corresponding to a second phase to transfer a second light wave with a second peak frequency with a time-delay difference relative to the first light wave. The first phase delay and the second phase delay are configured to change equally upon a change of temperature. The time-delay difference between the first light wave and the second light wave is set to be inversed value of a free spectral range (FSR) to align at least the first peak frequency to a channel of a designated frequency grid.

A demodulator can include an optical resonator. The optical resonator can include a resonant cavity that extends between a first surface that is partially reflective and a second surface that is at least partially reflective. The first surface can receive a phase-modulated optical signal that has a time-varying phase. The resonant cavity can accumulate resonant optical signal energy based at least in part on the phase-modulated optical signal. The first surface can direct a fraction of the resonant optical signal energy out of the optical resonator to form an intensity-modulated optical signal that has a time-varying intensity. A data detector can receive at least a portion of the intensity-modulated optical signal and, in response, generate an intensity-modulated electrical signal that has a time-varying intensity that corresponds to the time-varying phase of the phase-modulated optical signal.

Disclosed are optical communications systems and optical receivers including one or more optical cavity resonators. In particular, disclosed are methods and apparatus that allow for beam pointing to be maintained while permitting the receiver to tune the optical resonator to suit the wavelength, data rate and modulation format of the incoming optical signal, without requiring a coherent receiver or adaptive optics in addition to optical resonators.

A receiver is configured to detect, at a communication interface, a received signal that suffers from degradations incurred over a communication channel. The receiver applies an adaptive filter to a series of received blocks of a digital representation of the received signal, thereby generating respective filtered blocks. The receiver calculates coefficients for use by the adaptive filter on an j.sup.th received block as a function of (i) error estimates associated with an (j−D−1).sup.th filtered block, where D is a positive integer representing a number of blocks, and where j is a positive integer greater than (D−1); and (ii) delay compensation terms dependent on an estimate of a difference between coefficients used by the adaptive filter on an (j−D−1).sup.th received block and coefficients used by the adaptive filter on an (j−1).sup.th received block

To provide a technology in which a differential phase modulation manner can be applied to a space environment for satellite mounting, the optical receiver 10 includes a digital signal processing unit has: a level fluctuation frequency suppression unit 320 which suppresses a level fluctuation frequency component of the peak signal; an optical delay interference control unit 330 which generates an optical delay interference control signal, which is overdrive-amplified, on the basis of the peak signal of which the level fluctuation frequency component is suppressed and applies the generated optical delay interference control signal to the optical delay interferometer 210; and a data recovery unit 310 which recovers output data on the basis of the main signal from the wideband balanced optical detector 240.

During operation, the system receives an optical input signal, and also receives a reference optical frequency comb (OFC) signal. Next, the system uses a gapless spectral demultiplexer to spectrally slice the optical input signal to produce a set of spectral slices. The system also uses a high-contrast demultiplexer to strongly isolate each combline of the reference OFC signal to produce a set of reference comblines. Next, in a parallel manner, the system demodulates each spectral slice in the set of spectral slices centered on a single reference combline in the set of reference comblines to produce a set of baseband I/Q signals, wherein each spectral slice is demodulated based on a known code sequence. The system then digitizes the set of baseband I/Q signals to produce a set of digitized signals. Finally, the system processes the set of digitized signals to directly reconstruct a waveform for the optical input signal.