Systems and methods for performing wavelength conflict detection are provided. These are to detect situations in optical networks where two instances of the same wavelength channel have been added. Wavelength conflict detection is performed for each of a plurality of possible wavelength channels that could be present in an optical signal, each wavelength channel that is present modulated by a pilot tone signal with a respective pilot tone frequency, the pilot tone signal carrying M-ary pilot tone data, M=2.sup.n, n≧1, with a respective one of M different sequences being used to represent each of M possible data values over a data value period. Conflict detection for each wavelength channel involves performing correlation peak detection using each of the M different sequences to determine correlation peaks for each of the M different sequences, and, based on the determined correlation peaks, determining whether multiple instances of the wavelength channel are present in the optical signal.

Provided is a chromatic dispersion compensation method including: dividing a reception signal obtained by receiving an optical signal using a coherent detection scheme into a plurality of frequency bands; adjusting a timing on a time axis of the reception signal for each of the divided frequency bands; performing combination processing for combining the reception signals included in the plurality of frequency bands; performing chromatic dispersion compensation on the reception signal at any timing before or after the combination processing; selecting, before the combination processing, sections in which overlapping parts determined based on lengths of overlap parts are generated; outputting the reception signal for each of the selected sections as a division processing block; and removing the overlap parts from both ends of a processing block generated by combination of the division processing blocks in the combination processing so as to be continuous on a frequency axis.

A coherent optical spectrum analyser for monitoring a spectrum of a fibre link is provided. The coherent optical spectrum analyser comprises an input connectable to the fibre link, the input being connected to a first input of a coherent detector having at least two input, the first and a second input, and an output. The coherent optical spectrum analyser further comprises a local oscillator having an output connected to the second input of the coherent detector, wherein the output of the coherent detector is connected to a first input of a processing unit, the processing unit also being connected to an input of the local oscillator, the processing unit being configured for analysing information from the coherent detector. The local oscillator comprises a semiconductor laser tuned by temperature to a specific wavelength and swept by changing a bias current, the local oscillator being controlled by the processing unit.

An information processing apparatus, includes: a memory that stores a wavelength defragmentation program; and a processor that performs, based on the wavelength defragmentation program, operations of: selecting an optical line according to a specific sequence in design information to allocate optical lines for respective optical wavelengths within a network; moving a selected optical line to a move-to optical wavelength; stopping, when movement of the selected optical line to the move-to optical wavelength is difficult, a selection of the optical line according to the specific sequence; and selecting a new optical line from optical lines indicated in a priority list.

A frequency offset detection method in an optical spectrum measurement device, implemented by a controller, includes determining a reference optical spectrum based on expected channels and their associated spectral occupancy without extracting any information from actual received optical spectrum; obtaining a measured optical spectrum from the optical spectrum measurement device; and performing a frequency offset control loop using the reference optical spectrum and the measured optical spectrum to correct frequency offset in the optical spectrum measurement device. The optical spectrum measurement device can be an Optical Channel Monitor and the measured optical spectrum can include optical channels partially overlapping one another in Nyquist or in super-Nyquist spacing.

An optical spectrum analyzer (OSA) for measuring an optical spectrum of an input optical signal in a measurement wavelength range is provided. The OSA comprises a modulator, an integrated optical filter, and a photodetector. The modulator modulates the input optical signal by applying a dither modulation to facilitate detection and noise rejection. The integrated optical filter, which may include a ring resonator system, is sequentially tunable to selectively transmit each wavelength of the modulated optical signal in the measurement wavelength range. The photodetector sequentially detects each wavelength of the modulated optical signal in the measurement wavelength range to provide a representative output electrical signal.

An optical wavelength and optical power measurement device is provided. The optical wavelength and optical power measurement device includes: an input unit in which an optical connector that emits communication light of an infrared ray wavelength region is connected; a filter unit that separates the communication light of an infrared ray wavelength region and light of a visible ray wavelength region; a sensing unit that communicates with a path of the communication light of an infrared ray wavelength region of the filter unit and in which a signal of the communication light of an infrared ray wavelength region is input; and an inspection unit that communicates with a path of the light of the visible ray wavelength region of the filter unit and that inspects a surface of the optical connector.

There is provided a transmission apparatus including: generators to generate optical signals having wavelengths included in a predetermined band, the wavelengths being variable; a transmitter to multiplex the optical signals and transmit the optical signals to another transmission apparatus; a memory; and a processor coupled to the memory and the processor to: monitor reception quality of an optical signal for monitoring received by the another transmission apparatus while changing a wavelength of the optical signal for monitoring which is generated by the generators, determine a first wavelength of a first optical signal having a longest wavelength and a second wavelength of a second optical signal having a shortest wavelength, based on the reception quality monitored, determine a wavelength of an optical signal except for the first and second optical signals, based on the first second wavelengths, and control the wavelength generated by the generators, based on the wavelength determined.

An optical device may include a dispersion element. The optical device may include a reflective optic to reflect an optical beam with a fixed offset perpendicular to a dispersion direction of the dispersion element and with a negative offset in the dispersion direction of the dispersion element. The reflective optic may be aligned to the dispersion element to offset an optical beam with respect to the dispersion element and to cause the optical beam to pass through the dispersion element on a plurality of passes, offsetting the optical beam on each of the plurality of passes.

Communication of light signals and optical cables can be managed to mitigate error associated with using optical cables to communicate light signals. A communication management component (CMC) can embed respective timing synchronization pulses in respective lights signals having respective wavelengths. The light signals can be typical light signals or can be squeezed and twisted to generate a desired twisted light signal. The light signals can be transmitted via the optical cable to a receiver. A CMC, at the receiver end, can determine error associated with the transmission of the light signals via the optical cable and respective characteristics of the respective light signals, including respective arrival times of the respective timing synchronization pulses and respective light intensity or power levels of the respective light signals. From the respective characteristics, CMC can determine a compensation action to perform mitigate the error with regard to subsequent transmissions of light signals.