Abstract: Spatial division multiplexing (SDM) allows multiple optical signals to be multiplexed onto a single optical link. Performance of SDM systems may be improved by monitoring performance metrics indicative of crosstalk between the spatially multiplexed signals and adjusting at least one transmission characteristic of one or more of the multiplexed signals in order to reduce the impact of the intermodal crosstalk.

Abstract: An analog radio over fiber (AROF) wavelength division multiplexing (WDM) system and method for reducing adjacent channel leakage ratio (ACLR) in a radio frequency signal provided by an AROF WDM system are provided. The AROF WDM system comprises a plurality of transmitters, a multiplexer, a demultiplexer, a plurality of receivers and a controller. Each transmitter is for receiving a radio frequency input signal and for modulating the radio frequency input signal onto an optical signal to obtain a modulated optical signal. The multiplexer is for receiving each modulated optical signal from the plurality of transmitters and for combining the modulated optical signals into a combined optical signal to be sent a distance over an optical fiber. The multiplexer has a pluralities of passbands with each passband having a center wavelength. The demultiplexer is for receiving the combined optical signal and for separating the combined optical signal back into the individual modulated optical signals.

Abstract: An analog radio over fiber (AROF) wavelength division multiplexing (WDM) system and method for reducing adjacent channel leakage ratio (ACLR) in a radio frequency signal provided by an AROF WDM system are provided. The AROF WDM system comprises a plurality of transmitters, a multiplexer, a demultiplexer, a plurality of receivers and a controller. Each transmitter is for receiving a radio frequency input signal and for modulating the radio frequency input signal onto an optical signal to obtain a modulated optical signal. The multiplexer is for receiving each modulated optical signal from the plurality of transmitters and for combining the modulated optical signals into a combined optical signal to be sent a distance over an optical fiber. The multiplexer has a pluralities of passbands with each passband having a center wavelength. The demultiplexer is for receiving the combined optical signal and for separating the combined optical signal back into the individual modulated optical signals.

Abstract: Spatial division multiplexing (SDM) allows multiple optical signals to be multiplexed onto a single optical link. Performance of SDM systems may be improved by monitoring performance metrics indicative of crosstalk between the spatially multiplexed signals and adjusting at least one transmission characteristic of one or more of the multiplexed signals in order to reduce the impact of the intermodal crosstalk.

Abstract: A spatial mode multiplexer for multiplexing optical signals onto different spatial modes includes an optical path for directing a probe signal through a mode converter of the multiplexer. A spatial profile of an optical phase of the probe signal is detected e.g. by splitting the reference signal into monitoring and reference paths to produce an interference pattern that can be captured and processed to control the spatial mode converters.

Abstract: An optical system for coupling an optical signal into an orbital angular momentum (OAM) mode of an OAM optical fiber is disclosed. The system includes a first detector array for capturing an input image, a processor for processing the input image to determine modal purity and for generating a feedback signal based on the modal purity and a spatial light modulator (SLM) having an array of pixels that are adjustable in response to the feedback signal. This system improves modal purity and lessens modal crosstalk.

Abstract: A system and method are presented for coupling OAM optical beams to optical fibers. The system may include, for instance, an OAM beam generator, for receiving one or more of a plurality of input signals, and generating a different OAM mode signal for each input signal. The OAM beam generator may further be operative to adjust a location and/or an exit angle of the one or more OAM mode signals before sending the one or more OAM mode signals to a beam combiner that combines the one or more OAM mode signals into a combined mode OAM transmission. The system may further include a controller in communication with at least one crosstalk estimate sensor and the at least one OAM beam generator, the controller operative to optimize the crosstalk estimate by receiving the crosstalk estimate for one of the OAM mode signals, and sending control instructions instructing the OAM beam generator to adjust a location and/or an exit angle of the one or more OAM mode signals to reduce the crosstalk estimate.

Abstract: A digital-electrical to analog-optical converter for converting a N-bit digital data signal uses a non-linear optical element that is susceptible to the Kerr effect. N digitally modulated optical bit stream sources are co-polarized and modulated according to individual bit streams of the digital data. The co-polarized digitally modulated signals interact with a polarized probe signal in the optical element causing the polarization of the probe signal to be changed. Propagating the polarization-changed probe signal output from the optical element through a polarizer provides an amplitude modulated optical signal corresponding to the N-bit digital signal.

Abstract: A digital-electrical to digital-optical converter converts the digital electric signal to a plurality of digital-optical signals. The plurality of digital signals are used in controlling one or more cross phase modulator semiconductor optical amplifiers (XMP-SOAs) in order to modulate a continuous wave optical signal and produce an analog-optical signal corresponding to the digital-electrical signals.

Abstract: A digital-electrical to analog-optical converter for converting a N-bit digital data signal uses a periodically poled non-linear waveguide connected to (i) N optical signals each modulated by a corresponding bit stream of the N-bit digital data signal, (ii) N pump optical signals and (iii) a probe optical signal to generate an output optical signal having an amplitude corresponding to the N-bit digital data signal. The output optical signal is filtered out from other optical signals output from the periodically poled non-linear waveguide by an optical filter.

Abstract: A digital-electrical to digital-optical converter converts the digital electric signal to a plurality of digital-optical signals. The plurality of digital signals are used in controlling one or more cross phase modulator semiconductor optical amplifiers (XMP-SOAs) in order to modulate a continuous wave optical signal and produce an analog-optical signal corresponding to the digital-electrical signals.