Abstract: A method for phase compensation in an optical communication network includes (1) modifying a modulated signal according to one or more correction factors to generate a compensated signal, to compensate for phase rotation, (2) modulating a magnitude of an optical signal in response to a magnitude of the compensated signal, and (3) modulating a phase of the optical signal, after modulating the magnitude of the optical signal, in response to a phase of the compensated signal.

Abstract: An optical communication system includes N optical modules at the local end. Each optical module includes a first optical interface and a second optical interface. A first optical interface of a first optical module in each of the N optical modules at the local end is connected to a peer end through a common optical fiber. A second optical interface of an ith optical module in the N optical modules at the local end is connected to a first optical interface of an (i+1)th optical module in the N optical modules at the local end, and i=1, 2, . . . , N?1.

Abstract: Techniques for driving a directly modulated laser whilst correcting non-linearities an optical output waveform, based on generating a modulating current waveform that approximates an ideal modulating current that produces a linear optical output waveform. The techniques enable useful, practical approximations to the ideal modulating current to be determined.

Abstract: A gain equalization apparatus according to an example embodiment includes a first path including a gain equalizer configured to correct a tilt of an input optical signal, a second path including a through-fiber configured to transmit the input optical signal therethrough as it is, an optical switch capable of switching between the first path including the gain equalizer and the second path including the through-fiber, at least one memory configured to store instructions, and at least one processor configured to execute the instructions to control the switching of the optical switch. By this configuration, a gain equalization apparatus and a method for equalizing a gain capable of reducing power consumption and suppressing an increase in optical loss while improving reliability are provided.

Abstract: Provided is an optical transmission system including: an optical transmission apparatus; an optical reception apparatus; a communication device that is a delay measurement target; and a transmission device that transmits a signal between the optical reception apparatus and the communication device, in which the optical transmission apparatus includes a main signal transfer unit that transmits a main signal, the transmission device transmits, to the optical reception apparatus, a first main signal transmitted from the optical transmission apparatus and transmitted via the communication device and a second main signal transmitted from the optical transmission apparatus and not transmitted via the communication device, and the optical reception apparatus includes a reception processing unit that measures a delay occurring in the communication device by using the first main signal and the second main signal transmitted from the transmission device.

Abstract: A backbone network (100) for use in an optical wireless communication system comprises one or more local switches (200) and one or more optical access points (300), APs, wherein local switches (200) are configured to provide to optical APs (300) connections to an external network. Each local switch (200) comprises a first type optical front end (210), OFE, having a rotatable orientation and a beam angle not larger than 60 degrees, and a second type OFE (230) having a 360-degree beam angle on the rotation plane of the first type OFE. Each optical AP comprises an OFE (310) having a rotatable orientation and a beam angle not larger than 60 degrees. The pairing and beam alignment between the first type OFE of a local switch and the OFE of an optical AP is achieved via the assist of the second type OFE of the local switch.

Abstract: A long-distance DWDM lightwave transmission system operating in the 2000 nm wavelength region is proposed that is based on the utilization of hollow core fiber configured to exhibit low loss (e.g., on the order of 0.02 dB/km) in combination with a hybrid TDFA/HDFA repeater device. Multiple concatenated spans of the combination of the hollow core fiber and hybrid TDFA/HDFA repeater device are able to provide communication over path lengths in excess of 10,000 km without the need for electronic regeneration of the propagating signals. In one case, the hollow core fiber is configured as a double-nested anti-resonant nodeless fiber (DNANF) with the number of nested structures and their various parameters optimized to provide the low loss operation in the 2000 nm region.

Abstract: In an optical communication network including a plurality of communication apparatuses being connected by a transmission path transmitting WDM signal light in which a plurality of optical signals are performed wavelength division multiplexing, a network management apparatus includes an addition control unit that controls a first communication apparatus, when the first communication apparatus adds the optical signal to the WDM signal light, in such a way as to add, to be adjacent to each other, a plurality of the optical signals to be dropped by a second communication apparatus to a wavelength band being sandwiched between guard bands, and a drop control unit that controls the second communication apparatus, when the second communication apparatus drops the optical signal from the WDM signal light.

Abstract: A signal transmission system for transmitting a main process variable and further data between a field device and a superordinate unit, includes a first conversion arrangement, a second conversion arrangement and an optocoupler arrangement. The optocoupler arrangement is connected between the first conversion arrangement and the second conversion arrangement. The first conversion arrangement is configured to convert at least the further data exchanged between the field device and the superordinate unit into a data signal transmittable via the optocoupler arrangement. The optocoupler arrangement transmits the data signal between the first conversion arrangement and the second conversion arrangement. The second conversion arrangement converts the data signal to the further data and transmits it to the field device. A method transmits a main process variable and further data between a field device and a superordinate unit. In the method, at least the further data is transmitted via an optocoupler arrangement.

Abstract: A system includes a downconverter, an optical transmitter, an optical receiver, and an upconverter. The downconverter includes an LO1 circuit and a mixer. The LO1 circuit generates an LO1 signal synchronized with an LO synchronization signal. The mixer receives RF signals in first frequency bands and downconverts them to second frequency bands by mixing the RF signals with the LO1 signal. The optical transmitter modulates the downconverted RF signals and the LO synchronization signal onto optical beams and transmits the modulated optical beams over a fiber. The optical receiver demodulates the modulated optical beams to reconstruct the downconverted RF signals and the LO synchronization signal. The upconverter includes an LO2 circuit and a mixer. The LO2 circuit generates an LO2 signal responsively to the reconstructed LO synchronization signal. The mixer mixes the reconstructed RF signals with the LO2 signal to reconstruct the RF signals in the first frequency bands.

Abstract: An optical analog-to-digital converter (O-ADC) converts an input optical signal (IOS) into an output digital signal. The O-ADC includes ADC stages, each of which can generate an electrical bit of the output digital signal and an optical bit. An ADC stage can include a photodetector, an ADC circuit, and an optical output circuit. The photodetector generates an analog electrical signal based on a portion of the IOS. The ADC circuit generates a digital electrical signal (electrical bit) based on the analog electrical signal and a reference analog electrical signal, which is based on a portion of a reference optical signal (ROS). The optical output circuit provides an output optical signal (OOS) (optical bit) based on the digital electrical signal and the portion of the ROS. Photodetectors of subsequent ADC stages generate analog electrical signals based further on an OOS from an optical output circuit of a previous respective ADC stage.

Abstract: In one embodiment, a method for dispersion compensation by an optical transceiver includes: receiving an output from a digital signal processor of the optical transceiver; determining a difference between the received output and an initial target output; based on determining that the difference between the received output and the initial target output exceeds a threshold, tuning a temperature of a dispersion management device of the optical transceiver across a first temperature range; identifying an adjusted target output based on the temperature tuning across the first temperature range; and adjusting the temperature of the dispersion management device to an adjusted target temperature corresponding to the adjusted target output.

Abstract: A programmable filter for electronic signals. The filter includes an input that splits power of the input signal along two paths, a first and second path that is phase shifted by ninety degrees in respect of the first path. The first and second path are each modulated to the optical domain, and provided as input to respective filter chains. The in-phase signal can be filtered by IIR or FIR optical filters with configurable operation, as well the shifted signal can be filtered by a second chain of IIR and FIR optical filters with configurable operation. Resulting output from each filter chain is recombined and demodulated from the optical domain. In this manner, the electronic filter can adopt any suitable impulse response, including impulse responses described with complex coefficients. Real parts can be configured by operation of the first filter chain and imaginary parts by operation of the second filter chain.

Abstract: The systems and devices described provide for a user selectable CPO interface for both duplex and parallel optical network interfaces. The systems include a pluggable optical device with a laser source subassembly, an internal optical connector, a plurality of laser source optical paths connecting the laser source subassembly to the internal optical connector, and an external optical connector. The system also includes a plurality of transmit optical paths connecting the internal optical connector and the external optical connector and a plurality of receive paths connecting the internal optical connector and the external optical connector.

Abstract: A first device may generate optical signals of different polarizations. Photodiodes may use the optical signals to transmit wireless signals at different polarizations and at a frequency greater than 100 GHz using the optical signals. A second device may receive the wireless signals and may convert the wireless signals into optical signals. A Stokes vector receiver on the second device may generate Stokes vectors based on the optical signals. Control circuitry on the second device may use the Stokes vectors generated for a series of training data in the wireless signals to generate a rotation matrix that characterizes polarization rotation between the first and second devices. The control circuitry may multiply wireless data in subsequently received wireless signals by the rotation matrix to mitigate the polarization rotation and other transmission impairments while using minimal resources.

Abstract: A signal generator provides a periodic optical signal as output. The signal generator can be optically coupled to a splitter or other distribution network that transits the optical signal along multiple paths to terminate at different locations and/or for use by multiple electronic circuits. Each path can include a reflector element that reflects a portion of the signal back along the optical signal path. Reflections can be separated by operation of a circulator and photodiode. Output of the photodiode can be used to adjust phase and/or amplitude of optical signals traversing each optical signal path such that each electronic circuit receives an in-phase reference signal as input.

Abstract: A connection state identification system includes an identification information addition means and an identification information acquisition means. When an inspection optical signal, which is an optical signal for inspection transmitted by a first optical communication device to a second optical communication device, is received by the second optical communication device over inter-optical communication device optical paths, which are the optical paths included in the undersea optical cable system between the optical communication devices, the identification information addition means adds, to an unassigned frequency band of the inspection optical signal, the unassigned frequency band being a frequency band other than a frequency band assigned to optical communication, identification information differing for each inter-optical communication device optical path through which the inspection optical signal passes.

Abstract: Embodiments described herein provide for improved detection and correction of a polarity mismatch/swapped fiber without requiring manual intervention. The optical transceivers and methods provide improved detection and correction by determining receive (Rx) optical signals for an optical connection are not detected in a Rx path in an optical transceiver and, upon detecting the crossover Rx optical signals in the Tx path, implementing a crossover correction scheme in the optical transceiver to enable optical connections.

Abstract: According to an aspect of the present invention, there is provided an optical receiver in an optical transmission system that transmits an optical signal between an optical transmitter and an optical receiver connected via an optical fiber transmission path, the optical receiver including: a channel distribution estimation unit that estimates channel distribution information in a transmission direction based on the optical signal transmitted from the optical transmitter and a reference signal; and a non-linear compensation unit that performs non-linear compensation based on the channel distribution information estimated by the channel distribution estimation unit.

Abstract: Aspects of the subject disclosure may include, for example, generating a first set of optical signals, demultiplexing the first set of optical signals to generate demultiplexed signals, launching the demultiplexed signals into a medium, receiving from the medium a second set of optical signals, multiplexing at least a portion of the second set of optical signals to generate one or more multiplexed signals, obtaining one or more electrical signals according to one or more measurements of one or more optical fields of the one or more multiplexed signals, and generating one or more point spread functions from the one or more electrical signals. Other embodiments are disclosed.