A fiber optic sensing (FOS) system and method. The system may include one or more interrogator units and a proximal wavelength division multiplexer (WDM) and a distal WDM optically connectable to the one or more interrogator units, an upgoing transmission fiber, a down-going transmission fiber, and one or more downhole sensing fibers. The method may include transmitting one or more light pulses from an interrogator unit, multiplexing the one or more light pulses from the interrogator unit with a proximal WDM into an upgoing transmission fiber and a down-going transmission fiber, and receiving the one or more light pulses with a distal WDM. The method may further include multiplexing the one or more light pulses from the upgoing transmission fiber and the down-going transmission fiber into one or more downhole sensing fibers and receiving backscatter light from at least one of the one or more downhole sensing fibers.

A fiber optic sensing (FOS) system and method. The system may include one or more interrogator units and a proximal wavelength division multiplexer (WDM) and a distal WDM optically connectable to the one or more interrogator units, an upgoing transmission fiber, a down-going transmission fiber, and one or more downhole sensing fibers. The method may include transmitting one or more light pulses from an interrogator unit, multiplexing the one or more light pulses from the interrogator unit with a proximal WDM into an upgoing transmission fiber and a down-going transmission fiber, and receiving the one or more light pulses with a distal WDM. The method may further include multiplexing the one or more light pulses from the upgoing transmission fiber and the down-going transmission fiber into one or more downhole sensing fibers and receiving backscatter light from at least one of the one or more downhole sensing fibers.

Apparatuses and methods for far-end monitoring of transmitter IQ skew in a DSCM system are described. Soft symbols for a given subchannel and a corresponding mirror subchannel are used as joint inputs to a MIMO equalizer. The hard decision symbols for the given subchannel and mirror subchannel are used as references to compute the equalizer coefficients. An estimated phase or estimated transmitter IQ skew is computed for at least the given subchannel using the equalizer coefficients. The computation is repeated to obtain estimated phase or estimated transmitter skew for all subchannels. The transmitter IQ skew is computed using the estimates from all subchannels. The computation is performed for each polarization. The computed transmitter IQ skew is communicated back to the transmitter via optical path (for correcting the skew).

An apparatus for management of a spectral capacity of a wavelength division multiplexing, WDM, system includes at least one pair of transmission fibers provided for transporting optical signals. Each transmission fiber of a transmission fiber pair is connected to a first port of an optical circulator having at least two additional ports and adapted to transmit an incoming optical signal entering one of its ports via its next port. WDM subsystems configured with counter-propagating assignable wavelengths are connected to associated ports of the optical circulator of the apparatus.

Techniques are described for implementing an out-of-band communication channel used to exchange control channel information in sub-carrier-based optical communication systems. In an example implementation, an optical communication system includes a primary transceiver, a component, and secondary transceivers. The primary transceiver is operable to supply first optical subcarriers to an optical communication path, the first optical subcarriers being amplitude modulated at a first frequency to carry first control information and amplitude modulated at a second frequency to carry second control information. The component is operable to be coupled to the optical communication path and includes circuitry operable to detect the first control information. The secondary transceivers are coupled to a terminal end of the optical communication path. At least one of the secondary transceivers is operable to detect the second control information and block the first control information.

A fiber distribution device includes a swing frame chassis pivotally mounted to a support structure. At least a first optical splitter module is mounted to the swing frame chassis. Pigtails having connectorized ends are carried by the swing frame chassis and have portions that are routed generally vertically on the swing frame chassis. An optical termination field includes fiber optic adapters carried by the swing frame chassis. The fiber optic adapters are configured to receive the connectorized ends of the pigtails.

A fiber distribution device includes a swing frame chassis pivotally mounted to a support structure. At least a first optical splitter module is mounted to the swing frame chassis. Pigtails having connectorized ends are carried by the swing frame chassis and have portions that are routed generally vertically on the swing frame chassis. An optical termination field includes fiber optic adapters carried by the swing frame chassis. The fiber optic adapters are configured to receive the connectorized ends of the pigtails.

A LIDAR system includes a LIDAR assembly configured to output a LIDAR output signal that carries multiple different channels. A directional component has an optical grating that receives the LIDAR output signal from the LIDAR assembly. The directional component demultiplexes the LIDAR output signal into multiple LIDAR output channels that each carries a different one of the channels. The directional component is configured to steer a direction that the LIDAR output channels travel away from the LIDAR system.

Methods for configuring an optical link in which a distribution of transmission data rates and line rates are configured for a predetermined amount of optical bandwidth to maximize transmission capacity. In these methods, a controller of an optical network obtains input parameters that include a signal-to-noise ratio (SNR) for optical signals and an allocated bandwidth of the optical link, further obtains, for each line rate, a mapping of transmission data rates along a frequency spectrum of the allocated bandwidth compatible with the SNR, and generates a channel plan in which a number of traffic modes and a distribution of a plurality of channels in the allocated bandwidth are set to maximize transmission capacity. The plurality of channels is used for transmitting the signals on the optical link. The controller configures at least one optical network element in the optical network to establish the optical link based on the channel plan.

An optical communication device includes a WDM optical transmission reception unit that receives an optical signal and converts the optical signal to an electric signal, a MUX/DEMUX unit that converts the electric signal obtained by the conversion to a plurality of electric signals, signal detection units, a switch unit that changes paths, client IF units, and a control unit. A first signal detection unit among the signal detection units detects a first electric signal among the plurality of electric signals. When the first electric signal is a signal to be processed based on a first communication standard, the control unit controls the switch unit so that the first electric signal is inputted to a client IF unit that executes a process based on the first communication standard among the client IF units.