A data communication system comprises an optical transferring device, optical network units, and user processors. The optical transferring device splits a received optical signal into split optical signals. Each optical network unit transforms a respective split optical signal into M first electronic signals, M>1. Each user processor comprises an input mapping unit to map the respective M first electronic signals into N second electronic signals, N?M; an equalization processor to equalize the N second electronic signals and generate a set of N equalized electronic signals; a wave-front demultiplexer to perform a wave-front demultiplexing transform on the N equalized electronic signals, and output N wave-front demultiplexed signals, each of the N wave-front demultiplexed signals being a unique linear combination of the N equalized electronic signals; and an output mapping unit to map the N wave-front demultiplexed signals into at least M third digital electronic data signals.

An optical signal detecting apparatus and method. The optical signal detecting apparatus includes an optical demultiplexer configured to demultiplex an input optical signal into a first optical signal having a first band wavelength and a second optical signal having a second band wavelength, a first optical detector configured to detect the first optical signal, and a second optical detector configured to detect the second optical signal, and the optical demultiplexer, the first optical detector, and the second optical detector may be provided in a TO-CAN package.

An apparatus includes a demultiplexing device, a bank of filters, a wavefront processor, and an optimizer. The demultiplexing device demultiplexes M data streams into N wavefront signals which include P pilot signals, N, M, and P being positive integers and N>M. The bank of filters filters the N wavefront signals using filter weights. The wavefront processor, having N input ports and N output ports, performs an N-to-N wavefront demultiplexing transform on the N wavefront signals at the N input ports and outputs N wavefront demultiplexed signals at the N output ports such that each of the N wavefront demultiplexed signals is a linear combination of the N wavefront signals. The N wavefront demultiplexed signals include P recovered pilot signals. The optimizer updates the filter weights using performance indices based on the P recovered pilot signals and known pilot signals corresponding to the P pilot signals.

A system for transmitting data, images, and audio to and from an aerially moved payload, the system having one or more media converters for converting coax signals to fiber signals and at least two wave division multiplexers, one for combining two or more distinct fiber signals into a single fiber signal and one for splitting the two or more combined fiber signals back into two distinct fiber signals. The system also includes at least one line along which one or more of data, images, and audio may be transmitted to and from the aerially moved payload.

Methods, systems, and devices for implementing optical interface and multiplexing devices. An input optical signal is received over an input fiber by an optical interface device. A modulated optical signal and an unmodulated optical signal are demultiplexed from the input optical signal, the unmodulated optical signal is modulated based on a data signal to generate an output optical signal; and the output optical signal is transmitted over an output fiber. A modulated optical signal is received over a network connection from an optical network by an optical multiplexing device. An unmodulated optical signal is generated using a generator device; the unmodulated optical signal and a signal that includes the modulated optical signal are multiplexed using an optical multiplexer to generate an output signal; and the output signal is transmitted over an output fiber to the optical interface device.

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. Each receiver is for receiving one of the modulated optical signals from the demultiplexer and for converting the received modulated optical signal into a radio frequency output signal. The controller is configured to detune, for each transmitter, one of that transmitter and the multiplexer relative to the other such that a wavelength of the modulated optical signal transmitted by that transmitter is longer than the center wavelength of a corresponding one of the plurality of passbands of the multiplexer.

Optical fiber data communications are described. A comb laser can provide light at a first wavelength and a second wavelength. Using that light, polarization multiplexing circuitry can generate an optical signal having different polarization components and transceivers can transmit the optical signal having the first wavelength and a probe having the second wavelength via an optical fiber. A polarimeter can determine characteristics of the polarization of the probe. Based on the characteristics, a polarization controller can adjust a polarization of the optical signal. The optical signal can then be split into different polarization components.

A method of interrogating a WDM optical communication system is provided to obtain one or more performance parameters. In accordance with the method, an optical probe wavelength is generated and possibly modulated in a prescribed manner. The probe signal is transmitted along a selected optical path through the WDM optical communication system for a duration of time that is less than a response time of network elements that impact signal quality along the selected optical path.

A system is provided for high speed optical fiber data transmission by generating artificial wavefronts along multiple paths exhibiting spatial mutual orthogonality. Multiple independent signal streams are structured over a group of different propagation paths that are coherently organized by wavefront multiplexing and dc-multiplexing techniques. Therefore, signal streams with enhanced throughput and reliability may be fully recovered at destinations via embedded diagnostic signals and optimization loops. Multiple optical channels are matched with multiple orthogonal wavefronts created by a signal pre-processor. A receiving end signal post-processor dynamically aligns propagation paths via diagnostic signals and orthogonality of the propagation wavefronts electronically. The multiple optical channels are coherently bonded into a single virtual channel, thereby increasing data bandwidth while reducing interference and unwanted multi-path effects. The wavefront multiplexing and de-multiplexing functions may be performed in a dedicated signal processor or may reside in a general-purpose microprocessor located in the user terminal.

A wavelength demultiplexer is equipped with a spectroscopic means (which separates light that is input from multiple input light paths, and outputs the light to multiple output light paths) and a light path switching device (a device that switches the light paths that are input to the spectroscopic means, with the switching being performed by an external operation), and the light path switching device may be a device that distributes the input from one input port to multiple output ports. The light path switching device and the spectroscopic means are polarization-independent, with the input light paths, the output light paths, and the light paths between the light path switching device and the spectroscopic means being polarization-maintaining light paths, so the relative polarization configuration is the same for the input light and the output light.