摘要:
The present invention relates to an optical receiver, in which the transmittance of a Mach-Zehnder interferometer can be locked at a normal operation point in a simple structure and control.A transmittance detecting circuit and a minute modulation signal detecting circuit are provided in parallel after a balanced optical receiver, and a switch is selectively connectable either a minute modulation signal detecting circuit and a transmittance detecting circuit. In the initial stage of frequency pull-in, the switch is set to connect the transmittance detecting circuit to the synchronous detection circuit. If the transmittance detecting circuit detects that the transmittance of the Mach-Zehnder interferometer at the carrier frequency becomes a desired transmittance, the connection of the switch is switched from the transmittance detecting circuit to the minute modulation signal detecting circuit.
摘要:
The present invention relates to an optical receiver, in which the transmittance of a Mach-Zehnder interferometer can be locked at a normal operation point in a simple structure and control. A transmittance detecting circuit and a minute modulation signal detecting circuit are provided in parallel after a balanced optical receiver, and a switch is selectively connectable either a minute modulation signal detecting circuit and a transmittance detecting circuit. In the initial stage of frequency pull-in, the switch is set to connect the transmittance detecting circuit to the synchronous detection circuit. If the transmittance detecting circuit detects that the transmittance of the Mach-Zehnder interferometer at the carrier frequency becomes a desired transmittance, the connection of the switch is switched from the transmittance detecting circuit to the minute modulation signal detecting circuit.
摘要:
An optical transmission system is provided in which the optimum operating point of a Mach-Zehnder interferometer, matched to the optical frequency of the light source on the transmitting side, can be set. The optical receiver (2) has an infinitesimal-modulated signal component detection circuit (222), which uses the signal train output from a balanced detection circuit (221) to detect the infinitesimal-modulated signal component applied to the phase adjustment terminal (201) of an MZI (200) by an infinitesimal-modulated signal oscillation circuit (224); a synchronous detection circuit (223), which synchronously detects the infinitesimal-modulated signals output from the infinitesimal-modulated signal component detection circuit (222) and infinitesimal-modulated signal oscillation circuit (224) and detects the error signal component arising from the shift between the optical signal carrier frequency and the optical frequency characteristic of the MZI (200); and a controller (207), which outputs a control signal to adjust the phase difference between two split optical signals output from the MZI (200) so as to correct the shift amount.
摘要:
An optical transmission system is provided in which the optimum operating point of a Mach-Zehnder interferometer, matched to the optical frequency of the light source on the transmitting side, can be set. The optical receiver (2) has an infinitesimal-modulated signal component detection circuit (222), which uses the signal train output from a balanced detection circuit (221) to detect the infinitesimal-modulated signal component applied to the phase adjustment terminal (201) of an MZI (200) by an infinitesimal-modulated signal oscillation circuit (224); a synchronous detection circuit (223), which synchronously detects the infinitesimal-modulated signals output from the infinitesimal-modulated signal component detection circuit (222) and infinitesimal-modulated signal oscillation circuit (224) and detects the error signal component arising from the shift between the optical signal carrier frequency and the optical frequency characteristic of the MZI (200); and a controller (207), which outputs a control signal to adjust the phase difference between two split optical signals output from the MZI (200) so as to correct the shift amount.
摘要:
An optical transmission system is provided in which the optimum operating point of a Mach-Zehnder interferometer, matched to the optical frequency of the light source on the transmitting side, can be set. The optical receiver (2) has an infinitesimal-modulated signal component detection circuit (222), which uses the signal train output from a balanced detection circuit (221) to detect the infinitesimal-modulated signal component applied to the phase adjustment terminal (201) of an MZI (200) by an infinitesimal-modulated signal oscillation circuit (224); a synchronous detection circuit (223), which synchronously detects the infinitesimal-modulated signals output from the infinitesimal-modulated signal component detection circuit (222) and infinitesimal-modulated signal oscillation circuit (224) and detects the error signal component arising from the shift between the optical signal carrier frequency and the optical frequency characteristic of the MZI (200); and a controller (207), which outputs a control signal to adjust the phase difference between two split optical signals output from the MZI (200) so as to correct the shift amount.
摘要:
The present invention relates to an automatic dispersion compensating optical link system. Carrier suppressed RZ encoded optical signals generated using carrier suppressing means and binary NRZ code or partial response code, or carrier suppressed clock signals generated using carrier suppressing means and clock signals are transmitted on an optical transmission line. Two bands of the carrier suppressed RZ encoded optical signals or carrier suppressed clock signals transmitted on the optical transmission line are each divided into bands and are received. Phase information of the respective basebands is extracted from the binary NRZ code components or partial response code components or clock signals in each band and the relative phase difference thereof is detected. The chromatic dispersion value of the optical transmission line is then calculated from the relative phase difference.
摘要:
The present invention suppresses to a minimum the degradation of the transmission quality caused by chromatic dispersion characteristic of an optical transmission medium, and the interplay between the chromatic dispersion and non-linear optical effects in dense WDM transport systems. A baseband input data signal is pre-coded in advance by a pre-coding unit, phase modulation is carried out using a pre-coded signal by the optical phase modulating unit, and the phase modulated optical signal is converted to an RZ intensity modulated signal by the optical filter unit that performs phase-shift-keying to amplitude-shift-keying conversion. For example, an optical phase modulating unit generates an encoded DPSK phase modulated signal using a differential phase shirt keying (DPSK) format, and a phase modulated signal is converted to an RZ intensity modulated signal by the optical filter unit disposed downstream of the optical phase modulating unit.