Patent ID: 7103275
Filing Date: 2006-09-05
Classification: H04B

Abstract:
1. An optical transmission system which transports information over fiber-optic transmission lines of upstream and downstream links, comprising: (a) an end station comprising: monitoring signal transmission means for transmitting over the upstream link a monitoring request signal including a monitoring command signal with a first optical wavelength and a response carrier wave with a second optical wavelength which is different from the first optical wavelength, the monitoring command signal requesting a specified repeater to provide information about operating status thereof, the response carrier wave being a carrier wave for the specified repeater to return the requested information as a monitoring response signal, and operating status receiving means for receiving the monitoring response signal and identifying the operating status of the specified repeater from the received monitoring response signal; and (b) a repeater comprising: an upstream optical coupler, attached to the upstream link, which has a first port for splitting off a part of upstream transmission signals including the monitoring request signal sent from said end station and a second port for taking out an optical signal that enters the first port, an upstream wavelength selection means, coupled to the first port of said upstream optical coupler, for selectively passing the first optical wavelength and reflecting back the second optical wavelength, thereby extracting the monitoring command signal from the monitoring request signal received through said upstream optical coupler while reflecting the response carrier wave back to the first port, monitoring control means, responsive to the monitoring command signal supplied from said upstream wavelength selection means, for collecting information about operating status of said repeater, and encoding the collected information into a response message signal, excitation means for supplying a pump beam into the fiber-optic transmission line of the upstream link to perform optical amplification using the fiber-optic transmission line as an amplifying medium, modulation control means, coupled to said excitation means, for modulating the pump beam with the response message signal, whereby the response message signal is superimposed on the response carrier wave propagating on the upstream link and the resulting monitoring response signal reaches said upstream optical coupler, and a downstream optical coupler, attached to the downstream link, which has a port to accept the monitoring response signal from the second port of said upstream optical coupler and direct the monitoring response signal into the downstream link for delivery to said operating status receiving means in said end station.