Abstract: A simple synchronizing detection circuit is provided in each of logical operation circuits, and a method for making a synchronizing detection in parallel is adopted. A selector control section monitors the states of the simple synchronizing detection circuits in parallel, and supplies an output from a proper logical operation circuit detecting the synchronization establishment to a frame synchronizing/terminating circuit at the latter stage. There is provided a function of relieving a synchronization determination condition if the synchronization establishment is not detected in any of the synchronizing detection circuits, whereby the output from the proper logical operation circuit can be selected depending on a load on a transmission path.

Abstract: There is provided an optical signal transmission apparatus having a stable dispersion compensation function without unnecessarily controlling a compensation value even when a main signal quality is deteriorated due to a factor other than dispersion or in the case of a transmission failure. When it is determined that a signal quality is deteriorated due to dispersion of a fiber by determining a control mode of a variable dispersion compensator by means of optical noise information and received power information in addition to bit error information of a received signal, a compensation value of the variable dispersion compensator is varied and a compensation value other than the dispersion of the optical fiber is held to an existing set value.

Abstract: In a transmission apparatus of a Gigabit Ethernet signal, in order to improve line efficiency, time division multiplexing is used. Further, if it is possible to branch/insert plural multiplexed Gigabit Ethernet signals at arbitrary nodes, it is possible to construct a more flexible network. For this reason, importance of a time division multiplexing apparatus having a function of branching/inserting Gigabit Ethernet signals is growing. A Gigabit Ethernet signal is monitored at the previous and subsequent stages of a cross connect unit, IFGs are inserted to the signal and switching is waited. If a signal state at the cross connection unit is an IFG, transmission path switching is performed, thereby performing transmission path switching without instantaneous interruption.

Abstract: A transmission apparatus is disclosed, which performs positive/negative stuffing with 8-bit/10-bit (8B/10B) codes being kept intact while retaining the normality of 8B/10B codes and the continuity of running disparity (RD) without termination of 8B/10B codes of a plurality of Gigabit Ethernet (GbE) signals received. The apparatus then executes multiplexing and separation after synchronization of the plurality of signals, thereby achieving the “transparent” transport of management information which is contained in the 8B10B codes between user devices.

Abstract: A simple synchronizing detection circuit is provided in each of logical operation circuits, and a method for making a synchronizing detection in parallel is adopted. A selector control section monitors the states of the simple synchronizing detection circuits in parallel, and supplies an output from a proper logical operation circuit detecting the synchronization establishment to a frame synchronizing/terminating circuit at the latter stage. There is provided a function of relieving a synchronization determination condition if the synchronization establishment is not detected in any of the synchronizing detection circuits, whereby the output from the proper logical operation circuit can be selected depending on a load on a transmission path.

Abstract: There is provided an optical signal transmission apparatus having a stable dispersion compensation function without unnecessarily controlling a compensation value even when a main signal quality is deteriorated due to a factor other than dispersion or in the case of a transmission failure. When it is determined that a signal quality is deteriorated due to dispersion of a fiber by determining a control mode of a variable dispersion compensator by means of optical noise information and received power information in addition to bit error information of a received signal, a compensation value of the variable dispersion compensator is varied and a compensation value other than the dispersion of the optical fiber is held to an existing set value.

Abstract: In a transmission apparatus of a Gigabit Ethernet signal, in order to improve line efficiency, time division multiplexing is used. Further, if it is possible to branch/insert plural multiplexed Gigabit Ethernet signals at arbitrary nodes, it is possible to construct a more flexible network. For this reason, importance of a time division multiplexing apparatus having a function of branching/inserting Gigabit Ethernet signals is growing. A Gigabit Ethernet signal is monitored at the previous and subsequent stages of a cross connect unit, IFGs are inserted to the signal and switching is waited. If a signal state at the cross connection unit is an IFG, transmission path switching is performed, thereby performing transmission path switching without instantaneous interruption.

Abstract: In the WDM systems, the OSNR and the signal loss among the optical signals are substantially minimized at the receiving terminal to combat the SRS effects. An equal amount of the signal loss is expected for every span in the transmission path so that the optical amplifier gain tilt is not affected among a number of wavelength frequencies in the optical signal. This is accomplished by controlling the amplification process according to a feedback from the monitoring units for monitoring the optical signal.

Abstract: In the WDM systems, the OSNR and the signal loss among the optical signals are substantially minimized at the receiving terminal to combat the SRS effects. An equal amount of the signal loss is expected for every span in the transmission path so that the optical amplifier gain tilt is not affected among a number of wavelength frequencies in the optical signal. This is accomplished by controlling the amplification process according to a feedback from the monitoring units for monitoring the optical signal.

Abstract: In the WDM systems, the OSNR and the signal loss among the optical signals are substantially minimized at the receiving terminal to combat the SRS effects. An equal amount of the signal loss is expected for every span in the transmission path so that the optical amplifier gain tilt is not affected among a number of wavelength frequencies in the optical signal. This is accomplished by controlling the amplification process according to a feedback from the monitoring units for monitoring the optical signal.

Abstract: A transmission apparatus is disclosed, which performs positive/negative stuffing with 8-bit/10-bit (8B/10B) codes being kept intact while retaining the normality of 8B/10B codes and the continuity of running disparity (RD) without termination of 8B/10B codes of a plurality of Gigabit Ethernet (GbE) signals received. The apparatus then executes multiplexing and separation after synchronization of the plurality of signals, thereby achieving the “transparent” transport of management information which is contained in the 8B10B codes between user devices.

Abstract: In the WDM systems, the OSNR and the signal loss among the optical signals are substantially minimized at the receiving terminal to combat the SRS effects. An equal amount of the signal loss is expected for every span in the transmission path so that the optical amplifier gain tilt is not affected among a number of wavelength frequencies in the optical signal. This is accomplished by controlling the amplification process according to a feedback from the monitoring units for monitoring the optical signal.

Abstract: In the WDM systems, the OSNR and the signal loss among the optical signals are substantially minimized at the receiving terminal to combat the SRS effects. An equal amount of the signal loss is expected for every span in the transmission path so that the optical amplifier gain tilt is not affected among a number of wavelength frequencies in the optical signal. This is accomplished by controlling the amplification process according to a feedback from the monitoring units for monitoring the optical signal.

Abstract: In the WDM systems, the OSNR and the signal loss among the optical signals are substantially minimized at the receiving terminal to combat the SRS effects. An equal amount of the signal loss is expected for every span in the transmission path so that the optical amplifier gain tilt is not affected among a number of wavelength frequencies in the optical signal. This is accomplished by controlling the amplification process according to a feedback from the monitoring units for monitoring the optical signal.