An optical communication device and related method are provided for reducing power variations among wavelength division multiplexing (WDM) signals. The device includes a dynamic gain equalizer (DGE) coupled to an optical communication path carrying WDM optical signals. The DGE is controlled in response to signals generated by an optical channel monitor (OCM). The OCM monitors signals coming into the DGE and monitors the signals leaving the DGE to thus monitor the WDM spectrum for optical signal power variations and adjust the DGE to reduce the signal power variations.

The present invention provides a signal processing apparatus, an optical line terminal, and a communications system. The signal processing apparatus includes a signal input interface, a signal output interface, a reset signal generation unit, a signal amplification and equalization unit, an enable signal generation unit, and N direct-current offset calibration loop units. The signal input interface is connected to the signal amplification and equalization unit, the signal amplification and equalization unit is connected to the signal output interface and the enable signal generation unit, the enable signal generation unit is connected to the N direct-current offset calibration loop units, the N direct-current offset calibration loop units are connected to the signal amplification and equalization unit, and the reset signal generation unit is connected to the N direct-current offset calibration loop units. The present invention can reduce an LA burst settling time, thereby reducing physical overheads of a link.

A distributed Automatic Power Optimization (APO) system and method are provided. The distributed APO system includes: one or more APO modules and a network management system. The one or more APO modules belong to one or more pre-divided APO links. Each APO module in the one or more APO modules belongs to only one APO link. The APO module is configured to, when the APO link to which the APO module belongs is triggered to perform power regulation, regulate a power attenuation or a gain between the two adjacent stations corresponding to the APO module and report a regulation result. The network management system is configured to, when learning that all of one or more APO modules in one APO link are successful in regulation, if there is a next APO link of the APO link, trigger the next APO link of the APO link to perform power regulation.

Methods and systems enable amplifying optical signals using a Bragg reflection waveguide (BRW) having second order optical nonlinearity to generate an optical pump by injection locking. The BRW may also be used for parametric amplification of optical signals using the optical pump. Feedback phase-power control may be performed to maximize output power.

The embedded apparatus disclosed herein may measure reflection coefficient values associated with back reflections in a fiber optics transmission system during a variable detection window to detect normal conditions, simulated Brillouin scattering (SBS), or excessive back reflections triggering remedial action. For example, the back reflections may indicate normal conditions if the reflection coefficients measured during an entire detection window remained below a threshold or a maximum reflection coefficient observed therein was below the threshold. Alternatively, the back reflections may trigger remedial action if the reflection coefficients measured in the entire detection window exceeded the threshold or a minimum reflection coefficient observed therein was above the threshold. Otherwise, the back reflections may indicate the SBS effect if the reflection coefficients measured during the detection window included points above and below the threshold or the minimum and maximum reflection coefficients observed therein were below and above the threshold.

An excitation light source apparatus capable of assuring an excellent optical transmission characteristic even at occurrence of a gain tilt is provided. The excitation light source apparatus comprises an excitation light outputting means, a control signal detection means, a control signal detection means, an excitation light control means, and a multiplexing means. The excitation light outputting means outputs excitation light for Raman amplification. The control signal detection means detects a control signal of the excitation light outputting means from beams of WDM signal light transmitted through optical fibers in an upstream direction and a downstream direction. The excitation light control means controls the excitation light outputting means, based on the control signal. The multiplexing means multiplexes the excitation light and each of the beams of the WDM signal light, and outputs the respective multiplexed beams of light to the optical fiber.

Wavelength multiplexed optical communication systems include a channeled chromatic dispersion compensator coupled to receive modulated optical beams associated with a plurality of optical channels at respective communication wavelengths. The channeled chromatic dispersion compensator applies independently selected dispersion compensations to each of the optical channels by identifying a dispersion compensation associated with a preferred bit error rate, inter-symbol interference, or other signal quality metric, or determined using optical fiber properties such as dispersion slope and zero dispersion wavelength. Chromatic dispersion compensation can be coupled with channel power equalization, and can be performed at a receiver or a transmitter or in the middle of a fiber span.

The invention relates to a device and a method performed by the device of monitoring an optical fibre link. The method provided for monitoring an optical fibre link comprises generating a monitoring signal used for monitoring the optical fibre link, combining the generated monitoring signal with a data signal to be transmitted over the optical fibre link, detecting backscattering of the monitoring signal from the optical fibre link, comparing the detected backscattered monitoring signal with an estimated monitoring signal backscattered along the optical fibre link, and determining, based on the comparison, at least one location along the optical fibre link where the monitoring signal is backscattered, and signal loss caused by the backscattering.

The present disclosure relates to an optical module having digital diagnostic monitoring functions and a circuit and method to control the optical module. In an embodiment, a control circuit for an optical module including an optical receiving unit and an optical transmitting unit may comprise a first memory for storing a plurality of configuration parameters at predefined locations within the first memory, a second memory for storing a plurality of variables at dynamically allocated locations of the second memory, the plurality of variables including variables corresponding to a current operation status of the optical module, and an analog-to-digital converter configured to receive an analog signal corresponding to the current operation status and convert the analog signal to a digital value to be stored as the variable corresponding to the current operation status in the dynamically allocated location of the second memory.

An optical reception apparatus (1) of the present invention includes: a local oscillator (11) outputting local oscillation light (22); an optical mixer (12) receiving a multiplexed optical signal (21) and the local oscillation light, and selectively outputting an optical signal (23) corresponding to the wavelength of the local oscillation light from the multiplexed optical signal; a photoelectric converter (13) converting the optical signal (23) output from the optical mixer into an electric signal (24); a variable gain amplifier (15) amplifying the electric signal (24) to generate an output signal (25) whose output amplitude is amplified to a certain level; a gain control signal generating circuit (16) generating a gain control signal (26) for controlling the gain of the variable gain amplifier (15); and a monitor signal generating unit (17) generating a monitor signal (27) corresponding to the power of the optical signal (23) using the gain control signal (26).