摘要:
A polarization scrambler has a polarization state rotating unit rotating the polarization state of a signal light, and a rotation speed controlling unit controlling the rotation speed of the polarization state in the polarization state rotating unit on the basis of the speed and scheme of modulation of the signal light, and the value of polarization mode dispersion of a transmission path on which the signal light is to be transmitted. Degradation of the transmission quality due to PMD is more mitigated than the known techniques.
摘要:
A polarization scrambler has a polarization state rotating unit rotating the polarization state of a signal light, and a rotation speed controlling unit controlling the rotation speed of the polarization state in the polarization state rotating unit on the basis of the speed and scheme of modulation of the signal light, and the value of polarization mode dispersion of a transmission path on which the signal light is to be transmitted. Degradation of the transmission quality due to PMD is more mitigated than the known techniques.
摘要:
A phase shift unit provides a prescribed phase difference (π/2, for example) between a pair of optical signals transmitted via a pair of arms constituting a data modulation unit. A low-frequency signal f0 is superimposed on one of the optical signals. A signal of which phase is shifted by π/2 from the low-frequency signal f0 is superimposed on the other optical signal. A pair of the optical signals is coupled, and a part of which is converted into an electrical signal by a photodiode. 2f0 component contained in the electrical signal is extracted. Bias voltage provided to the phase shift unit is controlled by feedback control so that the 2f0 component becomes the minimum.
摘要:
A phase shift unit provides a prescribed phase difference (π/2, for example) between a pair of optical signals transmitted via a pair of arms constituting a data modulation unit. A low-frequency signal f0 is superimposed on one of the optical signals. A signal of which phase is shifted by π/2 from the low-frequency signal f0 is superimposed on the other optical signal. A pair of the optical signals is coupled, and a part of which is converted into an electrical signal by a photodiode. 2f0 component contained in the electrical signal is extracted. Bias voltage provided to the phase shift unit is controlled by feedback control so that the 2f0 component becomes the minimum.
摘要:
A phase shift unit provides a prescribed phase difference (π/2, for example) between a pair of optical signals transmitted via a pair of arms constituting a data modulation unit. A low-frequency signal f0 is superimposed on one of the optical signals. A signal of which phase is shifted by π/2 from the low-frequency signal f0 is superimposed on the other optical signal. A pair of the optical signals is coupled, and a part of which is converted into an electrical signal by a photodiode. 2f0 component contained in the electrical signal is extracted. Bias voltage provided to the phase shift unit is controlled by feedback control so that the 2f0 component becomes the minimum.
摘要:
A phase shift unit provides a prescribed phase difference (π/2, for example) between a pair of optical signals transmitted via a pair of arms constituting a data modulation unit. A low-frequency signal f0 is superimposed on one of the optical signals. A signal of which phase is shifted by π/2 from the low-frequency signal f0 is superimposed on the other optical signal. A pair of the optical signals is coupled, and a part of which is converted into an electrical signal by a photodiode. 2f0 component contained in the electrical signal is extracted. Bias voltage provided to the phase shift unit is controlled by feedback control so that the 2f0 component becomes the minimum.
摘要:
An interferometer for demodulating a differential M-phase shift keying signal includes a PLC type interferometer main body, a heating portion that heats the PLC type interferometer main body, and an intermediate member having a higher stiffness than that of the PLC type interferometer main body, for bonding the PLC type interferometer main body and the heating portion with each other while being sandwiched therebetween. A linear expansion coefficient difference between the PLC type interferometer main body and the intermediate member is equal to or smaller than 4.5×10−6/° C., and a thermal conductivity difference between the PLC type interferometer main body and the intermediate member is equal to or larger than 10 W/mK. A phase of an optical signal flowing through the interferometer is adjusted by using the heating portion and a second heating portion.
摘要:
An interferometer for demodulating a differential M-phase shift keying signal includes a PLC type interferometer main body, a heating portion that heats the PLC type interferometer main body, and an intermediate member having a higher stiffness than that of the PLC type interferometer main body, for bonding the PLC type interferometer main body and the heating portion with each other while being sandwiched therebetween. A linear expansion coefficient difference between the PLC type interferometer main body and the intermediate member is equal to or smaller than 4.5×10−6/° C., and a thermal conductivity difference between the PLC type interferometer main body and the intermediate member is equal to or larger than 10 W/mK. A phase of an optical signal flowing through the interferometer is adjusted by using the heating portion and a second heating portion.
摘要:
An optical sender is disclosed that operates in a Differential Quadrature Phase Shift Keying modulation scheme for high speed optical transmission and is capable of performing logical calculations at a low speed. The optical sender transmits a Differential Quadrature Phase Shift Keying (DQPSK) signal generated with modulation signals ρk and ηk so that a signal directly output from a signal receiver corresponding to the optical sender is in agreement with data signals Ik and Qk to be transmitted. The signal receiver is capable of modulation by DQPSK, and the modulation signals ρk and ηk are precoded by using the data signals Ik and Qk and the modulation signals one symbol earlier (ρk−1 and ηk−1) . The optical sender includes plural precoders that perform logical calculation simultaneously and in parallel on plural data signals one period after another period.
摘要:
A wavelength division multiplexing system according to the present art adjusts the amount of dispersion compensation (the amount of dispersion compensation of an NZ-DSF and a DCF) every all spans on the basis of the time slot when an intensity modulation signal transmitter outputs an intensity modulation signal and the wavelength interval when a wavelength coupler multiplexes a phase modulation signal (output from a phase modulation signal transmitter) and the intensity modulation signal.