A polarization tracking device that tracks polarization fluctuation of light using a Stokes vector, includes: an updating unit configured to express a fluctuation amount of the Stokes vector on a Poincare sphere in an xy plane perpendicular to a travelling direction of a light wave using a first and a second angles, the first angle being an angle between a direction of an electric field of the light wave and y axis, and the second angle being a phase difference between a component of the optical electric field in a direction of the y axis and a component of the optical electric field in a direction of an x axis; and an application unit configured to rotate the Stokes vector using an inverse polarization rotation matrix expressed with the first and the second angles.

An optical transmission apparatus includes a wavelength converter that wavelength-converts input signal light using a nonlinear optical medium to output the converted signal light, a memory that holds first information relating to a wavelength conversion characteristic of the wavelength converter, a communication interface that receives second information relating to a second wavelength conversion characteristic of an adjacent optical transmission apparatus, and a control circuit that determines, using the first information and the second information when the second information is received, an excitation light frequency at which a gain deviation of main signal light subjected to a wavelength conversion is minimized to set the determined excitation light frequency in the wavelength converter.

A pluggable optical connector is configured to be insertable into and removable from an optical communication apparatus, and to be capable of communicating a modulation signal and a data signal with the optical communication apparatus. A wavelength-tunable light source is configured to output an output light and a local oscillation light. An optical transmission unit is configured to output an optical signal generated by modulating the output light in response to the modulation signal. An optical reception unit is configured to demodulate an optical signal received by using the local oscillation light to the data signal. Pluggable optical receptors are configured in such a manner that an optical fiber is insertable into and removable from the pluggable optical receptors, and configured to be capable of outputting the optical signal to the optical fiber and transferring the optical signal received thorough the optical fiber to the optical reception unit.

A technique is described to deterministically tune the emission frequency of individual semiconductor photon sources, for example quantum dots. A focused laser is directed at a film of material that changes form when heated (for example, a phase change material that undergoes change between crystal and amorphous forms) overlaid on a photonic membrane that includes the photon sources. The laser causes a localized change in form in the film, resulting in a change in emission frequency of a photon source.

A converter includes a combiner configured to polarization-combine a first pump light and a second pump light, a nonlinear medium configured to wavelength-convert first signal light into second signal light to output the second signal light after wavelength conversion from a second port, and to wavelength-convert the second signal light into first signal light to output the first signal light after wavelength conversion from the first port, a first circulator configured to input the first signal light from the first port into the nonlinear medium, and output the first signal light after wavelength conversion in the nonlinear medium from the first port, and a second circulator configured to input the second signal light from the second port into the nonlinear medium, and output the second signal light after wavelength conversion in the nonlinear medium from the second port.

One embodiment of the present invention provides an optical link coupling two nodes in an optical transport network. The optical link includes a fiber span, which includes a first optical fiber, a second optical fiber, and a splitter. The input of the splitter is coupled to an input of the fiber span, and first and second outputs of the splitter are coupled, respectively, to the first and second optical fibers. The optical link further includes a first amplifier coupled to the first optical fiber, a second amplifier coupled to the second optical fiber, and an optical switch. Two inputs of the optical switch are coupled to outputs of the first and second amplifiers, respectively; and an output of the optical switch is coupled to an input of a third amplifier.

The present disclosure provides a fiber laser light coherent combination system, comprising: a modulator module configured to perform a phase modulation on sub-beams according to pseudo-random sequences orthogonally independent from each other, and perform a frequency shift on a reference beam according to a set frequency; a fiber laser light amplifier module configured to perform a power amplification on the modulated sub-beams; a laser light collimation emission module configured to collimate and output the sub-beams and the reference beam; a combination sampling module configured to perform a combination of the sub-beams and the reference beam which are collimated and outputted, and convert them into an electrical signal; a digital phase modulation and demodulation module configured to perform a demodulation on the electrical signal according to the shifted frequency and each of the pseudo-random sequences, and obtain a phase difference between each of the sub-beams and the reference beam.

The present disclosure provides a fiber laser light coherent combination system, comprising: a modulator module configured to perform a phase modulation on sub-beams according to pseudo-random sequences orthogonally independent from each other, and perform a frequency shift on a reference beam according to a set frequency; a fiber laser light amplifier module configured to perform a power amplification on the modulated sub-beams; a laser light collimation emission module configured to collimate and output the sub-beams and the reference beam; a combination sampling module configured to perform a combination of the sub-beams and the reference beam which are collimated and outputted, and convert them into an electrical signal; a digital phase modulation and demodulation module configured to perform a demodulation on the electrical signal according to the shifted frequency and each of the pseudo-random sequences, and obtain a phase difference between each of the sub-beams and the reference beam.

A pluggable optical connector is configured to be insertable into and removable from an optical communication apparatus, and to be capable of communicating a modulation signal and a data signal with the optical communication apparatus. A wavelength-tunable light source is configured to output an output light and a local oscillation light. An optical transmission unit is configured to output an optical signal generated by modulating the output light in response to the modulation signal. An optical reception unit is configured to demodulate an optical signal received by using the local oscillation light to the data signal. Pluggable optical receptors are configured in such a manner that an optical fiber is insertable into and removable from the pluggable optical receptors, and configured to be capable of outputting the optical signal to the optical fiber and transferring the optical signal received thorough the optical fiber to the optical reception unit.

A method for transmitting and receiving an electromagnetic radiation beam, adapted to determine an orbital angular momentum of the received electromagnetic radiation beam, is described. There is further described a system for transmitting and receiving an electromagnetic radiation beam, capable of performing the aforesaid method. A method for performing a telecommunication of signals modulated according to any modulation technique and grouped by means of orbital angular momentum multiplexing is further described. There is further described a telecommunication system capable of performing the aforesaid method for performing a telecommunication of modulated signals.