Abstract: Aspects of the present invention include apparatus and methods for transmitting and receiving signals in communication systems. A multicarrier generator generates a multicarrier signal. An optical demultiplexer separates the multicarrier signal into separate multicarrier signals. At least one QPSK modulator modulates signals from the separate multicarrier signals. An optical multiplexer combines the QPSK modulated signals into a multiplexed signal. The multiplexed signal is then transmitted.

Abstract: A method and apparatus for determining in-band OSNR in optical information signals, e.g. in polarization-multiplexed QPSK and higher-order M-ary QAM signals, are disclosed. A correlation measurement of the signal amplitude or power at two distinct optical frequencies of the signal may be used to determine the in-band optical noise in the signal. A measurement of the signal power may be used to determine the OSNR based on the determined in-band noise.

Abstract: An optical communications beacon receiver including a camera for capturing a plurality of beacon images. The plurality of beacon images includes a beacon signal transmitted from a beacon transmitter. The beacon receiver also including processing circuitry configured for determining the state of the beacon signal for each of the plurality of beacon images based on the known pattern, at least one beacon image of the plurality of beacon images includes a beacon on state and at least one beacon image of the plurality of beacon images includes a beacon off state, comparing the at least one beacon image including the beacon on state to the at least one beacon image including the beacon off state, and determining a beacon location based on the comparison of the at least one beacon image including the beacon on state to the at least one beacon image including the beacon off state.

Abstract: Systems and methods for data transport, including submarine reconfigurable optical add/drop multiplexers, branching units configured to receive signals from trunk terminals (TTs), and dummy light filters configured to pass useful signals through the filters, and to reflect dummy light. Optical interleavers are configured to separate useful signals into two or more groups of optical channels, and the optical channels are set to a frequency of either a left or a right portion of a total channel bandwidth. De-interleavers merge signal groups together from trunk terminals, and lasers at each of the transponders at the source terminals are configured to adjust a destination of a channel by fine tuning a frequency or wavelength of the one or more signals.

Abstract: A communication device includes: a converter circuit configured to convert an optical signal that carries an oscillator signal of a radio frequency and transmission signals generated in a signal processing device into an electric signal; an extractor configured to extract the oscillator signal from the electric signal; a recovery circuit configured to recover the transmission signals from the electric signal; a radio frequency signal generator configured to generate radio frequency signals that respectively carry the transmission signals recovered by the recovery circuit using the oscillator signal; amplifiers respectively configured to amplify the radio frequency signals; antennas respectively configured to output the amplified radio frequency signals; a feedback circuit configured to generate a feedback signal from the amplified radio frequency signals; and a transmitter configured to convert the feedback signal into an optical signal and transmit it to the signal processing device.

Abstract: A Pulse Amplitude Modulated (PAM) optical device utilizing multiple wavelengths, features a communications interface having enhanced diagnostics capability. New registers are created to house additional diagnostic information, such as error rates. The diagnostic information may be stored in raw form, or as processed on-chip utilizing local resources.

Abstract: A Pulse Amplitude Modulated (PAM) optical device utilizing multiple wavelengths, features a communications interface having enhanced diagnostics capability. New registers are created to house additional diagnostic information, such as error rates. The diagnostic information may be stored in raw form, or as processed on-chip utilizing local resources.

Abstract: A system for communicating between an object in space and a ground station, between objects in space, or between ground stations, includes a telecentric lens. Photodetectors positioned upon a focal plane of the telecentric lens detect an inbound light beam, received from a source, that has passed through the telecentric lens to the focal plane. Lasers positioned upon the focal plane transmit light beams from the focal plane through the telecentric lens to an area that includes the source of the inbound light beam. A processor detect signals from individual photodetectors corresponding to light detected, and selectively signals individual lasers that are close to those photodetectors, resulting in a returning beam that arrives close to the source, and which carries encoded data.

Abstract: Systems and methods for autonomous signal modulation format identification are disclosed. In an example embodiment of the disclosed technology, a method includes mapping an input signal to Stokes space to generate a representation of the input signal in three-dimensional space. The method may further include determining the dimension of the representation and, based on the dimension, selecting a subset of modulation from a plurality of mutually exclusive subsets of modulation formats. Further, the method may include defining a cost function for identifying the modulation format from the selected subset and evaluating the cost function to identify the modulation format.

Abstract: A method for performing blind channel estimation for an MLSE receiver in a communication channel, according to which Initial Metrics Determination Procedure (IMDP) is performed using joint channel and data estimation in a decision directed mode. This is done by generating a bank of initial metrics that assures convergence, based on initial coarse histograms estimation, representing the channel and selecting a first metrics set M from the predefined bank. Then an iterative decoding procedure is activated during which, a plurality of decision-directed adaptation learning loops are carried out to perform an iterative histograms estimation procedure for finely tuning the channel estimation. Data is decoded during each iteration, based on a previous estimation of the channel during the previous iteration. If convergence is achieved, ISI optimization that maximizes the amount of ISI that is compensated by the MLSE is performed.

Abstract: A wavelength selective switch includes: N input ports, an input-side fiber array, an input-side collimator array, an input-side beam deformation and polarization conversion component, an input-side wave-demultiplexing component, an input-side switching engine, a focusing transformation lens group, an output-side switching engine, an output-side wave-combining component, an output-side beam deformation and polarization conversion component, an output-side collimator array, an output-side fiber array, and M output ports. The focusing transformation lens group includes two identical aspheric convex lenses that are placed in parallel, where a curvature from a center to an edge of a surface of the aspheric convex lens changes continuously.

Abstract: An optical transmitter converts a plurality of transmission signals transmitted via a plurality of lanes into a multi-carrier signal and transmits the multi-carrier signal. The optical transmitter includes: a controller configured to generate allocation information that indicates an allocation of sub-carriers to the plurality of lanes according to a bit rate of the transmission signal of each of the lanes and a possible transmission capacity of each of the sub-carriers; and a signal processor configured to convert the plurality of transmission signals into the multi-carrier signal in accordance with the allocation information generated by the controller.

Abstract: An optical communication system with a hierarchical branch configuration. The system includes first and second cable landing stations coupled to a trunk path in an optical cable. At least one hub-node is coupled to the trunk path through an associated hub-node branching unit. Sub-nodes are coupled the hub-nodes through associated sub-node branching units and sub-node paths in the optical cable. Sub-node signals may be communicated between the sub-nodes and the hub-nodes without being provided on the trunk path.

Abstract: Disclosed are an optical network unit included in an OFDMA-PON system that is capable of reducing OBI (optical beat interference), and a method of controlling the optical network unit. The disclosed optical network unit includes: a signal generator part configured to generate an electrical signal carrying transmission data; an RF tone generator part configured to generate an RF tone; a combiner part configured to combine the electrical signal and the RF tone; and a photoelectric converter part configured to convert the combined signal of the electrical signal and RF tone into an optical signal.

Abstract: An optical transmitter includes a DMT modulating unit that allocates information signals to SCs and that generates a DMT signal by performing multi-level modulation on each of the information signals allocated to each of the SCs. The optical transmitter includes a mixer that shifts, on the basis of the probe result of the DMT signal and frequency information on a wireless signal that is input, the carrier frequency of the wireless signal so as not to overlap the SC to which the information signal in the DMT signal is allocated. Furthermore, the optical transmitter includes a multiplexing unit that multiplexes the DMT signal received from the DMT modulating unit and the wireless signal in which the carrier frequency has been shifted and outputs the multiplexed signal.

Abstract: Embodiments of the present invention disclose a method, an apparatus, and a system for detecting an optical network. The method comprises: receiving, by a management device, a reflection peak power reported by a testing device, where the reflection peak power is a reflection peak power of an optical splitter that is obtained by the testing device according to a reflected optical signal, the reflected optical signal is an optical signal obtained by reflecting, by the optical splitter, a testing optical signal that is sent by the testing device and is transmitted to the optical splitter through an optical cable, and the optical splitter reflects the testing optical signal by using a reflective film disposed on an end surface of one optical output port. a detector does not need to carry a testing device to a site, to perform detection, efficiency of detecting performance of an optical network is improved.

Abstract: Systems, devices and techniques for receiving a signal comprising a quadrature duobinary modulated signal include performing channel equalization of the received signal using a constant multi-modulus to obtain a set of channel estimation coefficients and a stream of symbols, partitioning, based on modulus, the stream of symbols into three partitions, estimating carrier frequency based on the partitioned stream of symbols, recovering a phase of the signal using a maximum likelihood algorithm, and decoding the partitioned stream of symbols to recover data.

Abstract: Systems and methods for autonomous signal modulation format identification are disclosed. In an example embodiment of the disclosed technology, a method includes applying higher-order statistics to an input signal to identify the input signal's modulation format. The method may include applying higher-order statistics to the input signal to calculate higher-order cumulant values for the input signal as higher-order cumulants are indicative of a particular modulation format signature. The method may further include employing a decision tree to determine the modulation format of the input signal.

Abstract: A method is provided for carrying out channel performance monitoring in an optical communication system. The method comprising: receiving an optical signal; obtaining digitized samples associated with the optical signal; storing the digitized samples; carrying out an off-line processing of the stored samples. The off-line processing includes: using the digitized samples to determine information characterizing the at least one optical channel used for conveying the optical signal; using the determined information to estimate a value of at least one optical channel performance parameter characterizing the at least one optical channel; and forwarding the value of the at least one optical channel performance parameter to a network management element; and wherein the at least one optical channel performance parameter is estimated without a prior knowledge of information on a modulation format associated with the optical channel.

Abstract: Disclosed herein are a SATA host bus adapter using a optical signal and a method for connecting SATA storage using the optical signal. The SATA host bus adapter includes: a first conversion unit for converting a PCI-Express signal, transmitted from a host computer, into a data signal, using a protocol defined in a bus; a optical signal conversion unit for converting the data signal into a optical signal and for transmitting the optical signal to a optical signal reception unit; and a second conversion unit for converting the optical signal, received by the optical signal reception unit, into the data signal, for converting the data signal into a SATA signal, using the protocol, and for transmitting the SATA signal to the SATA storage.