Abstract: A master unit configured to manage a plurality of remote units connected in a ring topology, the master unit comprising: a network management section configured to transmit at least one of a path-state monitoring control signal and a delay measurement control signal to the plurality of remote units in a first direction and a second direction which is a reverse direction of the first direction, and receives an acknowledgement signal in response to the at least one of a path-state monitoring control signal and a delay measurement control signal; and switching control means for transmitting a forward signal received from a base station in the first direction, and transmitting a switching control signal in the second direction when a defect is detected in any remote unit among the plurality of remote units by the network management section.

Abstract: An optical transmission device includes a transmission unit, a filter unit, a detection unit, and a control unit. The transmission unit superimposes identical superimposition signals of a frequency modulation method on a plurality of optical signals that have identical destinations and that have adjacent wavelengths, and transmits resultant signals as one communication signal. The filter unit filters part of two optical signals having adjacent wavelengths from among the plurality of optical signals included in the communication signal. The detection unit generates an electric signal of a detection level representing an optical intensity of the two optical signals that were filtered by the filter unit. The control unit controls timings of superimposing the superimposition signals on the two optical signals respectively by controlling the transmission unit so that variation in the detection level becomes smaller.

Abstract: Methods and systems for transient gain cancellation at an optical amplifier may involve generating saturating light that is introduced in a reverse direction to a transmission direction at a doped fiber amplification element. The doped fiber amplification element may amplify an input optical signal having a plurality of wavelengths as well as the saturating light. The saturating light may be regulated by a control circuit to counteract transient gain effects of add/drop events in the input optical signal. The saturated light may be filtered to achieve a desired spectral profile.

Abstract: A scheme is described for remote control of the wavelength of a tunable transmitter in a smart small form-factor pluggable (SFP) transceiver, a smart SFP plus (SFP+) transceiver, a smart 10 gigabit small form-factor pluggable (XFP) transceiver, a smart duplex transceiver, a smart bidirectional (BiDi) transceiver, or a smart single wavelength single fiber (SWSF) BiDi-transceiver in a communication system using an operating system with Operation, Administration, and Maintenance (OAM) and Proprietary Protocol (PP) functions; an OAM, PP & Payload Processor; a transceiver; an optical spectrum analyzer; a bit error rate test (BERT); and an optical link in the field.

Abstract: An optical communication apparatus, in the sending side, distributes client signals according to destinations and a communication capacity of each destination, electrical-to-optical converts the distributed signals to optical signals having different center frequencies, and multiplexes the optical signals to output, and in the receiving side, the optical communication apparatus divides the wavelength division multiplexed signal to each wavelength (for each sending source), optical-to-electrical converts the divided optical signals to electrical signals, and multiplexes the electrical signals to output. An add/drop port of an optical route switching apparatus includes an input/output port to the optical communication apparatus, and an optical frequency bandwidth is variable according to an optical spectrum width of the optical signal. A network is constructed by using the optical communication apparatus and the optical route switching apparatus.

Abstract: Component signal values are derived from component signals and fed to at least one fixed equalizer which generates equalizer output signals. The signals are fed to phase error detectors generating phase error signals. The phase error signals are combined with further phase error signals derived by further error detectors receiving signal values from further equalizers and/or the component signal values directly from sample units.

Abstract: A system and method including a transmitter including digital signal processor for providing a shaped data output in response to an input data stream. The shaped data output is coupled to a modulator that modulates an optical signal in response to the shaped data output to provide a non-rectangular shaped output having channel spacing greater than Nyquist channel spacing. Providing a shaped output consistent the present disclosure mitigates the effects of non-linear impairments in an optical transmission system.

Abstract: Methods, architectures, circuits, and/or systems for monitoring operating parameters and/or generating status indications associated with electronic device operation are disclosed. The method can include (i) monitoring a first operating parameter related to operation of the electronic device to determine a first parameter value, (ii) calculating a difference between the first parameter value and a predetermined value for the first operating parameter, (iii) monitoring a second operating parameter on which thresholds for operational warnings and/or alarms are based to determine a second parameter value, (iv) updating or changing the thresholds based on a predetermined change or event in the second parameter value, (v) comparing the difference to the updated or changed thresholds, and (vi) generating a corresponding one of the operational warnings and/or alarms when the difference crosses at least one of the thresholds in a predetermined direction.

Abstract: A method, a system, and an apparatus for transmitting data information by using optical signals are disclosed. The method includes: selecting at least two optical carriers, where the at least two optical carriers correspond to at least two optical frequency slots, and a vacant optical frequency slot or an optical frequency slot occupied by other optical signals exists between the two optical frequency slots; modulating data information onto the at least two optical carriers to form a channel of optical signals, so that the channel of optical signals occupies the at least two optical frequency slots, and a vacant optical frequency slot or an optical frequency slot occupied by other optical signals exists between the two optical frequency slots; and sending the channel of optical signals.

Abstract: Aspects of the present invention include apparatus and methods for transmitting and receiving signals in communication systems. A beam splitter splits an optical signal into a plurality of signals. At least one QPSK modulator generates a plurality of QPSK modulated signals from the plurality of signals. An optical multiplexer combines the plurality of QPSK modulated signals into a multiplexed signal. The multiplexed signal is then transmitted.

Abstract: A system of thermally tuning an optical device is described. The system may include an optical device configured to output an optical signal. An amplitude of the optical signal may be dependent on a temperature of the optical device. The system may also include a control circuit, an adjust circuit, and a heater circuit. The control circuit may be configured to output a control current. The adjust circuit may be configured to perform an approximate square-root operation on the control current and to output a modified control current. The heater circuit may be coupled to the adjust circuit and may be configured to generate heat based on the modified control current. The heater circuit may also be positioned such that the generated heat affects the amplitude of the optical signal. The control circuit may linearly adjust the control current to approximately linearly adjust the heat generated by the heater.

Abstract: An optical access system is provided that enables subscriber terminals or termination devices to be interconnected via dedicated lines as needed, with respect to subscriber terminals or termination devices participating in an optical network. The optical network is a network connecting a plurality of accommodating stations, and in this network, the accommodating stations have a plurality of optical line termination devices and optical path selection means, the subscriber side optical terminals or optical line termination devices are connected in single star optical paths, and the optical line termination devices in the accommodating stations are connected with the above mentioned optical terminals or optical line termination devices via the optical path selection means.

Abstract: A fiber optic system includes a transmitter configured to utilize a plurality of modulation formats and a receiver communicatively coupled to the transmitter and configured to utilize a plurality of modulation formats. The transmitter and the receiver are cooperatively configured to set a modulation format of the plurality of modulation formats based upon optical signal-to-noise ratio associated therewith. A flexible bandwidth adaptation method includes monitoring at least one aspect of an optical link at a network element, responsive to the at least one aspect, computing a new modulation scheme for the optical link, and, if a solution is found for the new modulation scheme, changing to the new modulation format.

Abstract: A coaxial line terminal (CLT) comprising an optical port configured to couple to an optical line terminal (OLT) via an optical distribution network (ODN), an electrical port configured to couple to a coaxial network unit (CNU) via an electrical distribution network, and a processor coupled to the optical port and the electrical port, wherein the processor is configured to receive from the OLT a plurality of first frames addressed to the CNU, receive from the OLT a plurality of second frames not addressed to the CNU, forward the first frames to the CNU, and prohibit the second frames from being forwarded to the CNU.

Abstract: A system includes an optical power meter operable to generate an optical power signal corresponding to the optical power of a received output signal generated by an optical IQ-modulator. The system further includes a processor operable to receive the optical power signal and determine, based on a minimization algorithm and the received optical power signal, a first bias voltage to be applied to a first sub-modulator of the optical IQ-modulator and a second bias voltage to be applied to a second sub-modulator of the optical IQ-modulator. The system may also include a peak power meter operable to generate a peak power signal corresponding to the peak power of the received output signal generated by the optical IQ-modulator, wherein the processor is further operable to determine, based on a minimization algorithm and the received peak power signal, a third bias voltage to be applied to a phase shift component of the optical IQ-modulator.

Abstract: Wireless communication systems are provided including a transmitter and a receiver. The transmitter is configured to transmit a first polarized signal and a second polarized signal to the receiver, and in accordance with an instruction from the receiver, halt transmission of the second polarized signal. The receiver is configured to receive the polarized signals from the transmitter, determine whether or not the reception quality of the second polarized signal is below a threshold, and if so, instruct the transmitter to halt transmission of the second polarized signal.

Abstract: In a method for optically transmitting data by means of a pulse-width-modulated light source (LED), a pulse duty factor (N) of a pulse width modulation is specified to set the brightness of the light source (LED). A bright time (T) is divided into at least a first and second partial bright time using at least one blanking so that the data (DATA) to be transmitted are encoded by the start and time length of the at least one blanking. The sum of the partial bright times within the pulse width modulation cycle substantially corresponds to the bright time according to the specified pulse duty factor.

Abstract: Systems and methods are provided for a low frequency AC comparison circuit. The low frequency AC comparison circuit includes circuitry configured to receive a monitoring signal generated by an optical detector, the monitoring signal being proportional to an amount of light generated by an optical transmission device that transmits based on a data signal that is received by an optical driver. The comparison circuit is further configured to generate a modulation current control signal that is transmitted to the optical driver based on a comparison of a low frequency AC component of the monitoring signal and a correlated low frequency AC component of the data signal.

Abstract: An apparatus comprises an optical port; a first optical transmitter; a second optical transmitter; a partially reflective mirror positioned between the first optical transmitter, the second optical transmitter, and the optical port; and an optical rotator positioned between the partially reflective mirror and the first optical transmitter.

Abstract: Described is a light module interlock system comprising: an optical cable enabled to transmit light of a first wavelength and a second wavelength different than the first wavelength; a first light module enabled to provide the first wavelength to the optical cable; a second light module enabled to provide the second wavelength to the optical cable; a sensor enabled to detect the first wavelength transmitted by the optical cable, the sensor located at an opposite end of the optical cable as the first light module; and an interlock in communication with the sensor, the interlock enabled to: disable the second light module when the sensor fails to detect the first wavelength, such that the second wavelength is no longer provided to the optical cable.