A method includes generating, using a transmitter, an optical signal for each fiber incoherently combined in a fiber bundle. The method also includes transmitting the optical signal from each fiber as pulses at a target. The method further includes receiving, using a receiver array, the pulses of the optical signals and identifying one or more parameters of the target based on the pulses of the optical signals.

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 optical signal transmission method according to an embodiment of the disclosure is an optical signal transmission method in which a processor performs at least part of each operation, and may include an operation of receiving a data stream, an operation of separating at least part of the data stream into three channels, modulating the separated data streams respectively according to M-ary frequency shift keying (M-FSK) scheme so as to produce an FSK modulated signal, an operation of combining a plurality of FSK modulated signals modulated respectively in the three channels, and producing a color modulated signal according to a bit-color mapping table set in advance, and an operation of transmitting the color modulated signal by controlling a light source of the same optical channel based on the color modulated signal.

An optical signal transmission method according to an embodiment of the disclosure is an optical signal transmission method in which a processor performs at least part of each operation, and may include an operation of receiving a data stream, an operation of separating at least part of the data stream into three channels, modulating the separated data streams respectively according to M-ary frequency shift keying (M-FSK) scheme so as to produce an FSK modulated signal, an operation of combining a plurality of FSK modulated signals modulated respectively in the three channels, and producing a color modulated signal according to a bit-color mapping table set in advance, and an operation of transmitting the color modulated signal by controlling a light source of the same optical channel based on the color modulated signal.

An optical transmitter, having an encoder and modulator, transmits a data signal. The encoder maps information bits of the data signal to a symbol in eight-dimensional (8D) constellation space spanned by vectors IXT1, QXT1, IYT1, QYT1, IXT2, QXT2, IYT2, QYT2, wherein I and Q are in-phase and quadrature components of an optical carrier, X and Y are orthogonal polarizations of the optical carrier, and T1 and T2 are two consecutive transmission time slots, by selecting the symbol from a set of constellation points in the 8D space. The modulator uses the symbol in the two consecutive transmission time slots to modulate two carrier waves, and to transmit the two carrier waves over the orthogonal polarizations of the optical carrier. The set of constellation points do not include any constellation point with parallel Stokes vectors in the two consecutive transmission time slots but comprise constellation points with orthogonal Stokes vectors.

A spatial optical transmitter modulates an optical signal of a single wavelength in accordance with a signal to be transmitted, divides the modulated optical signal into two, rotates polarizations of the two divided optical signals, and transmits the two optical signals as optical signals of two orthogonal polarizations to space.

A wireless optical transceiver, comprising: a light splitter for splitting light emitted from a light source into two lights; a data converter for dividing input data into a plurality of divided data in a symbol unit of a predetermined number of bits, and for converting values of a phase bit and a duty bit at a predetermined position in each of the divided data into a phase control signal and a blocking control signal; a modulator for polarization phase modulating two lights split according to the phase control signal, and for conveying or blocking two modulated polarized lights in response to the blocking control signal to modulate a pulse position; a polarized light combiner for generating a transmission optical signal by combining two polarized lights with a modulated polarization phase and a modulated pulse position; and a light amplifier for amplifying the transmission optical signal and transmitting it through a standby channel.

A receiver system is provided for receiving a coherent Pulse Amplitude Modulation (PAM) encoded signal. The receiver system may include an optical polarization component configured to modulate a polarization of the received coherent PAM encoded signal. The receiver system may further include a digital signal processor (DSP) configured to perform polarization recovery between the received coherent PAM encoded signal and the LO signal using a first control loop, and to perform phase recovery between the received coherent PAM encoded signal and the LO signal using a second control loop.

An apparatus for generating a time-delayed product of two independent signals includes a fixed-wavelength laser. A first optical modulator is optically coupled to the fixed-wavelength laser and configured to modulate a fixed wavelength optical carrier with a first input signal of a set of input signals. The apparatus also includes a tunable laser. A second optical modulator is optically coupled to the tunable laser and configured to modulate a tunable optical carrier with a second input signal of the set of input signals. The apparatus also includes a dispersive element coupled to the second optical modulator, a first optical detector coupled to the dispersive element, a third optical modulator optically coupled to the first optical detector and the first optical modulator, an optical 90-degree hybrid element optically coupled to the third optical modulator, and a plurality of optical detectors optically coupled to the optical 90-degree hybrid element.

An apparatus for generating a time-delayed product of two independent signals includes a fixed-wavelength laser. A first optical modulator is optically coupled to the fixed-wavelength laser and configured to modulate a fixed wavelength optical carrier with a first input signal of a set of input signals. The apparatus also includes a tunable laser. A second optical modulator is optically coupled to the tunable laser and configured to modulate a tunable optical carrier with a second input signal of the set of input signals. The apparatus also includes a dispersive element coupled to the second optical modulator, a first optical detector coupled to the dispersive element, a third optical modulator optically coupled to the first optical detector and the first optical modulator, an optical 90-degree hybrid element optically coupled to the third optical modulator, and a plurality of optical detectors optically coupled to the optical 90-degree hybrid element.