Optical transmission system with raman amplifiers comprising a supervisory system
AssigneeAlcatel
InventorsRoberto Avallone, Andrea Fregosi
Life of this patent
Estimating the term…
Abstract
An optical transmission system having a supervisory system of devices disposed along an optical link. Co-propagating Raman amplifiers are disposed along the optical link. Low frequency supervisory signals are superimposed on the optical signals traveling on the optical link by suitable modulators in the devices disposed along the line or by the same co-propagating Raman amplifiers. Regeneration of the supervisory signal is provided in at least one device disposed along the optical link in order to counteract attenuation introduced on the supervisory signal by the co-propagating Raman amplifiers.
Claims36
An optical transmission system comprising:
- at least a first and a second terminal station, optically connected with each other by an optical link, said first or said second terminal station being configured to send on said optical link at least a first optical signal having a first direction;
- at least a first pump source disposed along said optical link, said pump source being configured to send on said optical link a pump radiation in said first direction, so as to cause Raman amplification of said first optical signal;
- and
- at least one device disposed along said optical link;
- said device comprising:
- at least a first photodetector configured for converting a portion of said first optical signal in an electrical signal;
- and
- a first supervisory unit configured for amplifying said electrical signal, for extracting a first supervisory signal from said electrical signal, and for feeding said extracted amplified first supervisory signal to at least a first modulator connected to said optical link or to a driving circuit of said pump source, so as to superimpose said extracted amplified first supervisory signal on said first optical signal, wherein said first modulator is not said first pump source, and a network analyzer is coupled between said modulator and a photodiode.
An optical repeater comprising:
- at least a first optical fiber configured to carry a first optical signal in a first direction, at least a first pump source connected to said first optical fiber, said first pump source configured to send on said first optical fiber a pump radiation in said first direction, so as to cause Raman amplification of said first optical signal;
- at least a first photodetector configured for converting a portion of said first optical signal in an electrical signal;
- and
- a first supervisory unit configured for amplifying said electrical signal, for extracting a first supervisory signal from said electrical signal, and for feeding said extracted amplified first supervisory signal to at least a first
- modulator connected to said first optical fiber or to a driving circuit of said first pump source, so as to superimpose said extracted amplified first supervisory signal on said first optical signal.
A method for supervising an optical transmission system comprising an optical link between at least a first and a second terminal station, said method comprising:
- transmitting a first optical signal on said optical link in a first direction;
- sending on said optical link a pump radiation in said first direction, so as to cause Raman amplification of said first optical signal;
- converting, in a point along said optical link, a portion of said first optical signal into an electrical signal
- amplifying said electrical signal;
- extracting a supervisory signal from said electrical signal;
- and
- superimposing said extracted amplified supervisory signal on said first optical signal.
Dependencies are inferred from the claim text.