Abstract: Aspects of the present disclosure describe systems, methods, and structures that advantageously amplify optical signals through the effect of optical pump signals generated by a multicore laser diode and multicore rare-earth doped optical fiber in optical communication with a 3D waveguide structure and a multicore input signal fiber providing a plurality of optical signals for amplification.

Abstract: Aspects of the present disclosure describe methods of generating an optimized set of constellation symbols for an optical transmission network wherein the optimized constellation is based on GMI cost and considers both fiber nonlinearity and linear transmission noise.

Abstract: Aspects of the present disclosure describe systems, methods, and structures for providing C-band and L-band transmission exhibiting increased power efficiency by diverting a portion of C-band optical energy to an input of L-band optical amplifiers (C-seeding) while optionally employing circulators to eliminate the need for optical isolators.

Abstract: Aspects of the present disclosure describe systems, methods, and structures for providing bidirectional C-band and L-band transmission employing optical circulators which advantageously eliminates C\L WDM couplers while still blocking any backward amplified spontaneous emissions from optical amplifiers.

Abstract: [Problem] To provide an optical communication device and the like with which the optical signals output by multiple light output units can be set with an accurate wavelength interval. [Solution] An optical communication device equipped with: multiple light output units that output optical signals of mutually different wavelengths; a multiplexing unit that outputs a wavelength-multiplexed signal by multiplexing the multiple optical signals output from the multiple light output units; a reference light output unit that outputs reference light serving as a reference; a wavelength generation unit that, on the basis of the reference light, outputs multiple light beams having a wavelength interval in accordance with a prescribed frequency; and a wavelength control unit that controls the wavelength of the optical signals output by the light output units in accordance with the interference component between the wavelength-multiplexed signal and light with the wavelength of at least one of the multiple light beams.

Abstract: An optical communication substrate includes a plurality of cores to communicate optical signals; a rectangular input delivering a pump laser, and a shaped portion to combine the optical signals and the pump laser into a ring geometry at an output.

Abstract: Systems and methods for data transport in an optical communications system, including generating a pairwise optimized (PO) multi-dimensional signal constellation in a single stage. The PO multi-dimensional signal constellation is generated by selecting a pair of symbols from a received constellation with M symbols, defining and minimizing an objective function with one or more constraints to optimize the selected pair of symbols, and iteratively selecting and optimizing one or more different pairs of symbols from the received constellation until a threshold condition is reached. Neighbor symbols from the generated PO multi-dimensional signal constellation in each polarization are clustered to formulate a clustered PO multi-dimensional signal constellation, and data is modulated and transmitted in accordance with the clustered PO multi-dimensional signal constellation.

Abstract: Systems and methods for data transport in optical communications systems, including a transmitter for encoding a received information sequence by constructing an outer and inner quasi cyclic-low-density parity check (QC-LDPC) code. The encoding includes dividing the received information sequence into a plurality of messages of equal length, encoding each of the messages into a codeword to generate a plurality of outer codewords, cascading the plurality of outer codewords to generate a bit sequence, and executing inner encoding to encode each of the plurality of outer codewords into codewords in QC-LDPC inner code. A receiver decodes a received data stream based on the QC-LDPC inner code using two-phase decoding including iteratively performing at least one of inner/outer and outer/inner decoding until a threshold condition is reached.

Abstract: An optical transmission system includes: a terminal station device that transmits a wavelength multiplexed optical signal resulting from multiplexing an optical signal and dummy light; and an optical add-drop multiplexer that receives respective wavelength multiplexed optical signals transmitted from a plurality of the terminal station devices and performs add-drop processing on the wavelength multiplexed optical signals. The dummy light has a wavelength arrangement in which adjacent wavelengths are arranged with equal spacing, and the wavelength arrangement of the dummy light differs between the terminal station devices.

Abstract: Methods and systems for communication with a modified constellation are provided. One of the methods includes coding, by a transmitter in the user equipment, an input data stream into a constellation of symbols having at least two neighboring symbols therein which differ by more than one bit and which are separated by a modified Euclidean distance to increase a Gaussian white noise resiliency of the at least two neighboring symbols with respect to remaining symbols, the remaining symbols being separated by the Euclidean distance of exactly one bit. The method further includes modulating, by the transmitter, the symbol stream into a transmission stream.

Abstract: Methods and systems for communication with an optimized constellation include coding an input data stream to a symbol stream according to an optimized constellation that has a non-Gray bit mapping and that has neighboring points having more than one bit difference farther apart than neighboring points having one bit difference. The symbol stream is modulated onto a transmission signal and subsequently demodulated at a receiver to produce a received symbol stream. The received symbol stream is decoded to a bitstream according to an optimized constellation that has a non-Gray bit mapping and that has neighboring points having more than one bit difference farther apart than neighboring points having one bit difference.

Abstract: Aspects of the present disclosure are directed to the mitigation of multi-path interference from quasi-single-mode fiber using hybrid span configuration and digital signal processing wherein a hybrid span of quasi-single mode fibers and single-mode fibers are used to configure the hybrid span. Additional aspects are directed to introducing a low-baud rate sub-banding signal to reduce the number of DD-LMS taps required when compensating the multi-path interference as the low-baud rate signal requires fewer taps to cover a given range of MPI as compared to a high-baud rate signal. Finally further aspects are directed to an ALMS equalizer which further reduces the number of equalizer taps by shifting its center tap towards the right if higher-order modes transmit slower than a fundamental mode, otherwise the center tap is shifted to the left.

Abstract: A wavelength division multiplexing system and method featuring a wavelength monitor that is configured to receive a portion of a combined signal of wavelength division multiplexing channels and determine the wavelengths of each channel or the guardband between each channel in the combined signal. The wavelength monitor determines if there is excess laser drift for each channel in the combined signal. If excess laser drift is determined, feedback is sent to the transmitter for the signal with excess laser drift and the signal is adjusted to produce a target wavelength. The wavelength monitor may utilize optical intradyning in order to monitor the wavelengths of each channel in the combined signal.

Abstract: A wavelength division multiplexing optical transmission apparatus includes a plurality of polarization multiplexing optical modulation means, polarization-maintaining optical multiplexing means, and delay adjustment means. The polarization multiplexing optical modulation means generate a plurality of polarization multiplexed optical modulation signals having different wavelengths. The polarization-maintaining optical multiplexing means multiplexes the wavelengths of the polarization multiplexed optical modulation signals to generate a wavelength multiplexed optical signal (WDM). The delay adjustment means adjusts a delay such that light intensities of polarization multiplexed optical modulation signals having adjacent wavelengths in the wavelength multiplexed optical signal (WDM) vary inversely with respect to each other.

Abstract: [Problem] To provide an optical communication device and the like with which the optical signals output by multiple light output units can be set with an accurate wavelength interval. [Solution] An optical communication device equipped with: multiple light output units that output optical signals of mutually different wavelengths; a multiplexing unit that outputs a wavelength-multiplexed signal by multiplexing the multiple optical signals output from the multiple light output units; a reference light output unit that outputs reference light serving as a reference; a wavelength generation unit that, on the basis of the reference light, outputs multiple light beams having a wavelength interval in accordance with a prescribed frequency; and a wavelength control unit that controls the wavelength of the optical signals output by the light output units in accordance with the interference component between the wavelength-multiplexed signal and light with the wavelength of at least one of the multiple light beams.

Abstract: Methods and systems for communication with an optimized constellation include coding an input data stream to a symbol stream according to an optimized constellation that has a non-Gray bit mapping and that has neighboring points having more than one bit difference farther apart than neighboring points having one bit difference. The symbol stream is modulated onto a transmission signal and subsequently demodulated at a receiver to produce a received symbol stream. The received symbol stream is decoded to a bitstream according to an optimized constellation that has a non-Gray bit mapping and that has neighboring points having more than one bit difference farther apart than neighboring points having one bit difference.

Abstract: A system for carrier phase recovery, including a receiver for receiving one or more frames of L symbols. A phase estimator performs carrier phase estimation for the received frames of L symbols, and the resulting carrier phase estimates are stored in a non-transitory computer-readable storage medium. One or more rotators de-rotates the received frames of L symbols by one or more of the carrier phase estimates, and a data processor calculates a sum of the outputs of the L de-rotated signals raised to an nth power, and determines a real part of the sum. A minimum determination device determines a minimum of the real part of the sum with respect to the carrier phase estimates, and phase unwrapping and multiplier removal is performed if a minimum has been determined.

Abstract: Aspects of the present disclosure are directed to the mitigation of multi-path interference from quasi-single-mode fiber using hybrid span configuration and digital signal processing wherein a hybrid span of quasi-single mode fibers and single-mode fibers are used to configure the hybrid span. Additional aspects are directed to introducing a low-baud rate sub-banding signal to reduce the number of DD-LMS taps required when compensating the multi-path interference as the low-baud rate signal requires fewer taps to cover a given range of MPI as compared to a high-baud rate signal. Finally further aspects are directed to an ALMS equalizer which further reduces the number of equalizer taps by shifting its center tap towards the right if higher-order modes transmit slower than a fundamental mode, otherwise the center tap is shifted to the left.

Abstract: A polarization multiplexing optical transmitter of the present invention includes frequency dividing means (21) that performs frequency dividing on a clock signal having a Baud rate frequency, phase modulation means (8) that performs phase modulation on a light signal in accordance with the clock signal having undergone the frequency dividing, branching means (2) that branches the phase-modulated light into two light signals, delay means (10) that delays one branched light signal relative to the other branched light signal to generate light signals having phases inverted relative to each other, and polarization multiplexing means (5) that synthesizes the generated signals lights with orthogonal polarizations to generate a polarization multiplexed signal. Hence, the polarization multiplexing optical transmitter that can further improve the signal quality can be accomplished.

Abstract: At a receiver side, to enhance the performance of concatenated LDPC and TCM coding, an iterative decoding between TCM decoder and LDPC decoder enables improvement in the reliability of received LLRs of each symbol after each iteration. A SOVA output of the TCM is used for LDPC decoding, and then the updated LLRs from LDPC decoder are further looped back to the TCM decoder for the next iteration. In such a manner, the decoding performance could be significantly improved after just several iterations.