Abstract: An optical system includes: an optical module that sends and receives an optical signal; an optical switch that optically connects to the optical module; and a plurality of optical connectors that optically connect to the optical switch. The optical switch selectively connects at least one of the plurality of optical connectors to the optical module.

Abstract: An optical amplifier control apparatus according to the present invention includes control circuit 300; optical amplifiers 4, 5 respectively located on paths; a plurality of light sources 200, 201 that output excitation lights that differ in light intensity; and optical switch 32 that changes optical routes of excitation lights that are output from light sources 200, 201 and inputs the excitation lights to optical amplifiers 4, 5 as determined by control circuit 300. Control circuit 300 is provided with determination section 301 that determines which paths to allocate which excitation lights that differ in light intensity based on a parameter that relates to wavelength lights on a plurality of paths when wavelength lights of WDM signal light that propagate to one of the plurality of paths are optically amplified.

Abstract: An optical amplifier of the present invention includes: an optical amplifier circuit that amplifies input signal light and outputs the amplified light as output signal light; a first monitor for monitoring the presence or absence of the input signal light; and a control circuit that, when receiving a shutdown control signal, controls the optical amplifier circuit such that a shutdown control speed for reducing a level of the output signal light to zero differs according to the presence or absence of the input signal light.

Abstract: An optical amplifier control apparatus according to the present invention includes control circuit 300; optical amplifiers 4, 5 respectively located on paths; a plurality of light sources 200, 201 that output excitation lights that differ in light intensity; and optical switch 32 that changes optical routes of excitation lights that are output from light sources 200, 201 and inputs the excitation lights to optical amplifiers 4, 5 as determined by control circuit 300. Control circuit 300 is provided with determination section 301 that determines which paths to allocate which excitation lights that differ in light intensity based on a parameter that relates to wavelength lights on a plurality of paths when wavelength lights of WDM signal light that propagate to one of the plurality of paths are optically amplified.

Abstract: Methods and systems for controlling power fluctuations in a network including a plurality of nodes are disclosed. A node in the network may be configured to modify power levels in accordance with either an active state or an inactive state. The node may transition to an inactive state in response to a power change that exceeds a power change threshold. The role of the node in controlling the power fluctuation in the network is reduced in the inactive state.

Abstract: An optical amplifier of the present invention includes: an optical amplifier circuit that amplifies input signal light and outputs the amplified light as output signal light; a first monitor for monitoring the presence or absence of the input signal light; and a control circuit that, when receiving a shutdown control signal, controls the optical amplifier circuit such that a shutdown control speed for reducing a level of the output signal light to zero differs according to the presence or absence of the input signal light.

Abstract: An optical amplifier includes a detecting section configured to detect a part of an input optical signal from a first node on an input side optical fiber; and a rare earth element doped optical fiber amplifier configured to amplify a remaining part of the input optical signal supplied from the input side optical fiber by using an excitation optical signal supplied from a second node and to output the amplified optical signal as an output optical signal to an output side optical fiber. A control unit controls the excitation optical signal based on the detected part of the input optical signal by the detecting section without real time control based on the output optical signal.

Abstract: An optical transmission apparatus includes a transmitting unit for transmitting an optical signal with a specified wavelength, a multiplexing unit for multiplexing the optical signal with the specified wavelength and an optical signal with a wavelength other than the specified wavelength and outputting the multiplexed signal as a wavelength division multiplexed optical signal, an optical amplifier for amplifying the wavelength division multiplexed optical signal outputted from the multiplexing unit, a level detecting unit detecting a variation of an optical power of the wavelength division multiplexed optical signal inputted to the optical amplifier, and a level adjusting unit for adjusting, when a variation of the optical power of the wavelength division multiplexed optical signal is detected by the level detecting unit, a transmitting power of the optical signal with the specified wavelength transmitted from the transmitting unit so that an output power becomes a level before the variation.

Abstract: Methods and systems for controlling power fluctuations in a network including a plurality of nodes are disclosed. A node in the network may be configured to modify power levels in accordance with either an active state or an inactive state. The node may transition to an inactive state in response to a power change that exceeds a power change threshold. The role of the node in controlling the power fluctuation in the network is reduced in the inactive state.

Abstract: An optical amplifier includes a detecting section configured to detect a part of an input optical signal from a first node on an input side optical fiber; and a rare earth element doped optical fiber amplifier configured to amplify a remaining part of the input optical signal supplied from the input side optical fiber by using an excitation optical signal supplied from a second node and to output the amplified optical signal as an output optical signal to an output side optical fiber. A control unit controls the excitation optical signal based on the detected part of the input optical signal by the detecting section without real time control based on the output optical signal.

Abstract: An optical transmission apparatus includes a transmitting unit for transmitting an optical signal with a specified wavelength, a multiplexing unit for multiplexing the optical signal with the specified wavelength and an optical signal with a wavelength other than the specified wavelength and outputting the multiplexed signal as a wavelength division multiplexed optical signal, an optical amplifier for amplifying the wavelength division multiplexed optical signal outputted from the multiplexing unit, a level detecting unit detecting a variation of an optical power of the wavelength division multiplexed optical signal inputted to the optical amplifier, and a level adjusting unit for adjusting, when a variation of the optical power of the wavelength division multiplexed optical signal is detected by the level detecting unit, a transmitting power of the optical signal with the specified wavelength transmitted from the transmitting unit so that an output power becomes a level before the variation.

Abstract: A gain equalizer for two-way transmission includes first and second circulators which are common to upstream and downstream signals, and which are provided in series along an optical transmission path through which an optical signal is transmitted in two directions and partially constitute an upstream path and a downstream path, and a gain equalization circuit which has been inserted into at least one of the upstream and downstream paths and which equalizes the characteristics of all of channels of WDM (wavelength division multiplexing) signals passed therethrough.