The present invention relates to a communication system for receiving electromagnetic radiation (EMR) signals from a plurality of sources or directions. A communication system comprises a transmission section surrounding an antenna section. The transmission section can be made of concentric layers of lens elements, mirror elements, or refraction medium. The layers allow incoming EMR to be directed to the antenna section through reflection or refraction. The antenna section can be made of a plurality of antenna elements such that each antenna element detects incoming EMR signals from different angles of origin even when the signals are received simultaneously.

An optical communication network includes a downstream optical transceiver. The downstream optical transceiver includes at least one coherent optical transmitter configured to transmit a downstream coherent dual-band optical signal having a left-side band portion, a right-side band portion, and a central optical carrier disposed within a guard band between the left-side band portion and the right-side band portion. The network further includes an optical transport medium configured to carry the downstream coherent dual-band optical signal from the downstream optical transceiver. The network further includes at least one modem device operably coupled to the optical transport medium and configured to receive the downstream coherent dual-band optical signal from the optical transport medium. The at least one modem device includes a downstream coherent optical receiver, and a first slave laser injection locked to a frequency of the central optical carrier.

A coherent optical injection locking (COIL) apparatus generates multiple optical source outputs from a single optical source generated by a parent laser. The COIL apparatus includes a plurality of optical source generators each having a child laser, of lesser performance than the parent laser, that is injection locked to the single optical source. The optical source generators may have one or both of a shared configuration and a cascaded configuration that replicates the single optical source, or a single wavelength of the single optical source when it is a comb source.

An optical WDM system configured to use direct detection of communication signals that is compatible with electronic CD compensation on a per-channel basis. In an example embodiment, to enable full (e.g., amplitude and phase) electric-field reconstruction at the receiver, the optical WDM system uses a carrier-frequency plan according to which the carrier-frequency comb used at one end of the WDM link and the carrier-frequency comb used at the other end of the WDM link are offset with respect to one another by one half of the bandwidth of an individual WDM component transmitted therethrough. This frequency offset places each local carrier frequency at a roll-off edge of the corresponding incoming data-modulated signal. As a result, the corresponding combined optical signal beneficially lends itself to direct detection that can be followed by full electric-field reconstruction using a known self-coherent Kramers-Kronig method and then by conventional electronic CD compensation.

A phase ambiguity processing method and device are provided. The phase ambiguity processing method includes: deciding symbols on a Y polarization state and an X polarization state of a received signal, and mapping to obtain first bit information, where the received signal includes a plurality of first signals; checking and analyzing the first bit information to generate a first check result; judging the first check result to obtain a judgment result as to whether the received signal has phase ambiguity; acquiring at least one of the plurality of first signals in the received signal when the judgment result indicates that the received signal has phase ambiguity; performing phase rotation on the first signal to obtain a second signal; and checking and analyzing the second signal, storing the second signal so that the first signal is replaced with the second signal for decoding processing if a check result is normal.

To provide a method for performing phase control of coherent two light wave signals while maintaining coherence in the state of the light signal, and a device which realizes such a method, there is provided, as illustrated in FIG. 1, a phase adjustment device 1 for two light waves including: a two light wave source 3, a wavelength separator 5, a first phase modulator 7, and a second phase modulator 9, whereby coherent two light waves are used as input signals to perform wavelength separation of those input signals thereafter to control optical phases of the respective light signals thereafter to multiplex them by using a multiplexer 11, thus to be able to obtain an output signal of which optical phase has been adjusted.

An optical WDM system configured to use direct detection of communication signals that is compatible with electronic CD compensation on a per-channel basis. In an example embodiment, to enable full (e.g., amplitude and phase) electric-field reconstruction at the receiver, the optical WDM system uses a carrier-frequency plan according to which the carrier-frequency comb used at one end of the WDM link and the carrier-frequency comb used at the other end of the WDM link are offset with respect to one another by one half of the bandwidth of an individual WDM component transmitted therethrough. This frequency offset places each local carrier frequency at a roll-off edge of the corresponding incoming data-modulated signal. As a result, the corresponding combined optical signal beneficially lends itself to direct detection that can be followed by full electric-field reconstruction using a known self-coherent Kramers-Kronig method and then by conventional electronic CD compensation.

An optical transmission device includes a data duplicating unit that duplicates signals of each of the lanes subjected to symbol mapping and sets the number of the lanes to the number of lanes of a first number; a waveform converting unit that waveform-converts a signal that can take a value of a type of a second number into a signal that can take a value of a type of a third number larger than the second number; a polarity inverting unit that inverts polarity; a lane replacing unit that performs replacement of lanes in two or more lanes; and an optical-signal generating unit that converts electric signals of the signals of each of the lanes input from the lane replacing unit into optical signals and combines and outputs the optical signals of the lanes.

A width-tunable single-frequency fiber laser light source for coherent optical orthogonal frequency division multiplexing system including a chirped fiber grating with high reflectivity, a high gain optical fiber, a chirped fiber grating with low reflectivity, a single-mode semiconductor pump laser, an optical wavelength division multiplexer, an optical coupler, an optical circulator, and a tunable optical filter module is provided. The chirped fiber grating with low reflectivity and the chirped fiber grating with high reflectivity together serve as a front cavity mirror and a back cavity mirror of a resonant cavity to realize laser oscillation. After a laser with broad spectrum output from the optical wavelength division multiplexer is split by the optical coupler, a part of the laser passes through the optical circulator to enter the tunable optical filter module. A wavelength corresponding to any nominal center frequency stipulated by the ITU-T is selected by the tunable optical filter module, with a 3 dB spectral width of less than 0.1 nm, and is then injected back into the resonant cavity via the optical circulator and the optical coupler, and the resonant cavity is subjected to a self-injection locking.

A phase ambiguity processing method and device are provided. The phase ambiguity processing method includes: deciding symbols on a Y polarization state and an X polarization state of a received signal, and mapping to obtain first bit information, where the received signal includes a plurality of first signals; checking and analyzing the first bit information to generate a first check result; judging the first check result to obtain a judgment result as to whether the received signal has phase ambiguity; acquiring at least one of the plurality of first signals in the received signal when the judgment result indicates that the received signal has phase ambiguity; performing phase rotation on the first signal to obtain a second signal; and checking and analyzing the second signal, storing the second signal so that the first signal is replaced with the second signal for decoding processing if a check result is normal.