56 results about "Super-channel" patented technology

Methods and systems for mitigating effects of polarization dependent loss (PDL) in an optical network transmitting a multi-carrier optical signal comprising a plurality of subcarriers may involve assigning and modifying a state of polarization to each subcarrier prior to transmission. An assigned state of polarization for each subcarrier may be modified for the subcarrier in the digital domain and / or the optical domain. Various specific assignment methods may be used, including individual subcarrier assignment, subcarrier set assignment, arbitrary subcarrier group assignment, random assignment, and / or combinations thereof. The assigned states of polarization may be selected based on a resulting minimum PDL-induced peak-to-peak power variation over a sum of the subcarriers for all orientations of a principal axis of PDL.

A number of carriers are selected according to a modulation format and symbol rate to realize a superchannel having fixed capacity, for example. At a receive node, the superchannel is optically demultiplexed from a plurality of other superchannels. The plurality of carriers are then supplied to a photodetector circuit, which receives additional light at one of the optical signal carrier wavelengths from a local oscillator laser. An analog-to-digital converter (ADC) is provided in the receive node to convert the electrical signals output from the photodetector into digital form. The output from the ADC is then filtered in the electrical domain, such that optical demultiplexing of the carriers is unnecessary.

Consistent with the present disclosure, data, in digital form, is received by a transmit node of an optical communication system, and converted to an analog signal by a digital-to-analog converter (DAC) to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data forming a plurality of corresponding carriers. The carriers are modulated according to one of a plurality of modulation formats and then optically combined to form a superchannel of a constant maximum capacity, for example. Accordingly, the number of carriers and the bit rate for each carrier remain constant for each modulation format to realize a constant maximum capacity. The superchannel is then transmitted over an optical communication path to a receive node. At the receive node, the superchannel is optically demultiplexed from a plurality of other superchannels. The plurality of carriers of the superchannel are then supplied to a photodetector circuit, which receives additional light at one of the optical signal carrier wavelengths from a local oscillator laser. An analog-to-digital converter (ADC) is provided in the receive node to convert the electrical signals output from the photodetector into digital form. The output from the ADC is then filtered in the electrical domain, such that optical demultiplexing of the carriers is unnecessary.

A method, device, and apparatus that provide a means for generating a network frame that provides information related to one or more super-channels for data transmission, which are comprised of one or more sub-channels for data transmission, over which the network frame is transmitted are disclosed.

An optical transceiver including a multi-direction variable transmitter including multiple outputs with different subcarriers being directed to different ones of the outputs to go to different directions in a network, and a multi-direction variable receiver for receiving multiple inputs thereby enabling transmission direction in a network with the transceiver at subcarrier granularity and avoiding entire super-channel granularity and enabling unused subcarriers to be utilized for traffic in other directions or destinations and making switching granularity finer for flexibility in the network.

A method for transmitting data over an optical super-channel partitions the data unequally into a set of data streams for transmission over the set of sub-channels of the super-channel, such that a size of a first data stream for transmission over a first sub-channel is different than a size of a second data stream of the data for transmission over a second sub-channel. The method encodes each data stream of the data with an error correction code (ECC) having different ECC rates to produce a set of encoded data streams and transmits concurrently the set of encoded data streams over the set of sub-channels of the super-channel. Accordingly, the method uses an adaptive ECC for optical super-channels, such that a first ECC rate for encoding the first data stream is different than a second ECC rate for encoding the second data stream.

Consistent with the present disclosure, a coherent detector is provided that includes an optical hybrid that supplies optical signals including local oscillator light to a balanced detector. The amount of imbalance or “balance error” in the balanced detector is identified by comparing an output of the balanced detector and an output of a photodiode that receives a portion of an input optical signal provided to the optical hybrid. Based on the balance error, electrical signals generated by the balanced detector or the power of optical signals passing through (or output from) the optical hybrid circuit can be adjusted so that the balance error is minimized or reduced to zero. As a result, imbalance associated with the balanced detector is corrected so that unwanted currents and / or related electrical signals are cancelled out or substantially cancelled out. Such unwanted currents and / or related electrical signals are generated in response to noise in the local oscillator light as well as intensity noise associated with non-selected optical signals in a superchannel.

The disclosure relates to technology for constructing an optical network. A central node is selected among a plurality of nodes in the optical network, and each of the nodes is connected to the central node via a set of superchannels, wherein each of the superchannels includes sub-carriers and has a same data rate. The network resources between the central node and each of the plurality of nodes are managed by dynamically allocating the sub-carrier bandwidths to support communication among the plurality of nodes via the superchannels, and wavelength selective switching is performed among the superchannels at the central node.