Methods and systems for monitoring an optical network are described. An optical device may receive a data signal. The optical device may send the data signal to a test port. A measuring device may measure characteristics associated with the data signal.

An apparatus includes a reconfigurable optical add/drop multiplexer (ROADM) having an input port to receive a first optical signal from a second device. The ROADM also includes a first wavelength selective switch (WSS), in optical communication with the input port, to convert the first optical signal into a second optical signal, a loopback, in optical communication with the first WSS, to transmit the second optical signal, and a second WSS, in optical communication with the loopback, to convert the second optical signal to a third optical signal and direct the third optical signal back to the second device via the input port.

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.

A system may include a receiver configured to receive a communications signal from a transmitter and processing circuitry configured to: determine at least one frequency characteristic of the communications signal and compare the at least one frequency characteristic to at least one verified frequency characteristic stored by a memory associated with the processing circuitry to determine whether the transmitter is a verified transmitter. In some examples, the transmitter, receiver and communications signal are an optical transmitter, and optical receiver, and an optical signal, respectively.

An optical module has an optical amplifier that amplifies an optical signal in which multiple wavelengths are multiplexed, an optical demultiplexer that separates the multiple wavelengths from the optical signal having been amplified by the optical amplifier, a first photodetector that monitors the optical signal at an input side of the optical amplifier, a second photodetector that monitors each of the multiple wavelengths at an output side of the optical demultiplexer, and a control circuit that controls a center wavelength of a filter of the optical demultiplexer based upon a first output from the first photodetector and a second output from the second photodetector.

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).

A method for in-field calibration of a laser transmitter includes receiving, at an optical network unit (ONU), a downstream connection from an optical line terminal (OLT) where the ONU includes a Distributed Bragg Reflector (DBR) laser. The method further includes attempting to establish an upstream connection between the ONU and the OLT. When the ONU establishes the upstream connection to the OLT, the method also includes receiving, at the ONU, a message to initiate calibration of the ONU where the message is generated to indicate that the DBR laser is operating outside an operational state. The method further includes tuning, by the ONU, the DBR laser to the operational state by adjusting an injection current for the DBR laser.

According to examples, a wavelength identification and analysis sensor may include a wavelength transmitter, operably connectable to an input or output of a wavelength selective device of a wavelength division multiplex (WDM) network, to transmit test signals on a plurality of wavelengths into the input or output of the wavelength selective device of the WDM network. A wavelength analyzer is to detect returned signals from the input or output of the wavelength selective device of the WDM network, with each returned signal being associated with one of the transmitted test signals. Further, the wavelength analyzer is to analyze the returned signals and identify, based on the analysis of the returned signals, a wavelength associated with the input or output of the wavelength selective device of the WDM network.

An optical channel monitor (OCM) may include a modulator to provide a modulation signal and a local oscillator (LO) to provide a modulated LO signal. The modulated LO signal may be created by modulating an LO signal based on the modulation signal. The OCM may include a mixer to generate a pair of mixed optical signals. The pair of mixed optical signals may be generated based on mixing the modulated LO signal and an input optical signal. The OCM may include an optical detector to provide, based on the pair of mixed optical signals, a first electrical signal corresponding to a coherent mixture of the input optical signal and the modulated LO signal. The OCM may include a synchronous demodulator to provide, based on the first electrical signal and the modulation signal, a second electrical signal representative of the optical power spectrum of the input optical signal.

An apparatus includes a reconfigurable optical add/drop multiplexer (ROADM) having an input port to receive a first optical signal from a second device. The ROADM also includes a first wavelength selective switch (WSS), in optical communication with the input port, to convert the first optical signal into a second optical signal, a loopback, in optical communication with the first WSS, to transmit the second optical signal, and a second WSS, in optical communication with the loopback, to convert the second optical signal to a third optical signal and direct the third optical signal back to the second device via the input port.