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).

An avionics unit for an avionics network is disclosed having a light emitter to provide a modulated broadband optical signal. The avionics unit also includes a first optical interface and a second optical interface. The first optical interface is optically connected to the light emitter and is to receive a removable wavelength selective filter to extract a modulated narrowband optical signal from the modulated broadband optical signal. The second optical interface is optically connected to the first optical interface and is to output the modulated narrowband optical signal.

A process for detecting a detuning which currently exists at a wavelength splitter within an optical fibre transmission network, comprises assessing expected values relating to at least two light sub-carriers, and determining actual values relating to said at least two light sub-carriers. A wavelength shift value which quantifies the existing detuning is obtained from a comparison between the expected and actual values. The process may be completed with updating a tuning of a light source from which the sub-carriers are derived, so as to reduce the wavelength shift.

A passive optical network having an optical-signal monitor configured to monitor carrier-wavelength drifts during optical bursts transmitted between the optical line terminal and optical network units thereof. In an example embodiment, the optical-signal monitor uses heterodyne beating between two differently delayed portions of an optical burst to generate an estimate of the carrier-wavelength drift during that optical burst. The passive optical network may also include an electronic controller configured to use the estimates generated by the optical-signal monitor to make configuration changes at the optical network units and/or implement other control measures directed at reducing to an acceptable level the amounts of carrier-wavelength drift during the optical bursts and/or mitigating some adverse effects thereof.

A monitoring and calibration apparatus for an optical networking device such as ROADM is provided. Reflectors are integrated into the device, for example at the ends of optical interconnect cables. The reflectors reflect light in specific monitoring wavelengths and pass other wavelengths such as those used for communication. A light source emits monitoring light which is reflected by the reflector and measured by a detector to measure the integrity of optical paths. The optical paths can include optical cables and cable connectors. Path integrity between different modules of the device can therefore be monitored. Multiple reflectors, reflecting light in different wavelengths, can be placed in series along the same optical path and used to monitor multiple segments of the path. A wavelength selective switch (WSS) of the device can be used to route monitoring light to different optical paths. The WSS also operates to route communication signals in the device.

An on-chip wavelength locker may include an optical waveguide splitter to split an input optical signal received from a laser. The on-chip wavelength locker may include a plurality of integrated periodic optical elements, each to receive a respective portion of the input optical signal after splitting of the input optical signal by the optical waveguide splitter, and provide, based on the respective portion of the input optical signal, a respective periodic output optical signal of a plurality of periodic output optical signals. Each periodic output optical signal, of the plurality of periodic output optical signals, may be phase shifted with respect to other periodic output optical signals of the plurality of periodic output optical signals. The on-chip wavelength locker may include a plurality of integrated photodiodes to receive the plurality of periodic output optical signals in association with wavelength locking the laser.

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.

Devices, computer-readable media and methods are disclosed for determining reachability for a wavelength connection in a telecommunication network. For example, a processor deployed in a telecommunication network may calculate a fiber loss on a link in the telecommunication network using optical power measurements and determine that a destination node of a wavelength connection is not reachable via a path that includes the link based upon the fiber loss of the link that is calculated. In one example, the determining is based upon a number of links in the path, an effective fiber loss for each link in the path, a penalty for nodes in the path, and an acceptable loss value. The processor may further perform a remedial action in response to determining that the destination node of the wavelength connection is not reachable via the path.

An optical channel monitor is formed to include the capability to sense real-time changes in optical power across signal bands (optical power changes including, for example, a complete drop out of the signal band) and quickly measure the resulting spectrum, thus enabling the host to initiate advanced power balancing solutions that mitigate the extent of the power change until a permanent fix is provided. A set of signal band sensors is included with a conventional OCM, where each sensor includes a photodetector that is able to detect changes in operation along its associated incoming signal band. Control electronics are used to monitor the states of the photodetectors, with the ability to invoke an OCM scan of the complete wavelength range when a power change condition is flagged.

An apparatus for determining a position of a disturbance to an optical fibre assembly comprises a detector system that receives concurrently, from the optical fibre system, a first digital optical signal having a first wavelength and a second digital optical signal having a second wavelength. The apparatus monitors a common parameter of the first and second signals over time and determines respective times at which a change occurs in said parameter in each signal, the change arising from a disturbance to the optical fibre assembly. The apparatus uses the first and second times to determine a position of the disturbance.