Optical Supervisory Channel for High Span Loss Optical Communication Systems

An optical supervisory channel comprising:

• a transmit path that propagates optical supervisory signals to a high span loss optical fiber span;
• an optical WDM that adds the optical supervisory signals to the high span loss optical fiber span;
• a WDM that extracts the optical supervisory signals from the high span loss optical fiber span;
• a receive path that transmits the optical supervisory signals away from the high span loss optical fiber span;
• and
• an optical amplifier that is optically coupled into one of the transmit path and the receive path of the optical supervisory channel, the optical amplifier amplifying the optical supervisory signals outside of the high span loss optical fiber span.

An optical supervisory channel comprising:

• a transmit path that propagates optical supervisory signals in a high span loss optical fiber span;
• an optical WDM that adds the optical supervisory signals to the high span loss optical fiber span;
• a WDM that extracts the optical supervisory signals from the high span loss optical fiber span;
• a receive path that transmits the optical supervisory signals away from the high span loss optical fiber span;
• and
• a Raman optical pump source having an output that is optically coupled into the high span loss optical fiber span, the Raman optical pump source generating a Raman optical pumping signal that amplifies the optical supervisory signals.

An optical supervisory channel comprising:

• a transmit path that propagates optical supervisory signals in a high span loss optical fiber span;
• an optical WDM that adds the optical supervisory signals to the high span loss optical fiber span;
• a WDM that extracts the optical supervisory signals from the high span loss optical fiber span;
• a receive path that transmits the optical supervisory signals away from the high span loss optical fiber span;
• and
• an optical filter that is optically coupled into the optical supervisory channel, the optical filter suppressing at least one of amplified spontaneous emissions, Raman optical pumping signals that amplify optical supervisory signals, Raman optical pumping signals that amplify optical data signals, and optical data signals, thereby increasing a signal-to-noise ratio of the optical supervisory signals.

An optical supervisory channel comprising:

• a transmit path that propagates optical supervisory signals in a high span loss optical fiber span;
• an optical WDM that adds the optical supervisory signals to the high span loss optical fiber span;
• a WDM that extracts the optical supervisory signals from the high span loss optical fiber span;
• a receive path that transmits the optical supervisory signals away from the high span loss optical fiber span;
• and
• a forward-error correction encoder that adds forward-error correction signals to the optical supervisory signals and a forward-error correction decoder that corrects transmission errors in the optical supervisory signals.

A method of propagating optical supervisory signals in a high-span loss optical fiber span, the method comprising:

• generating optical supervisory signals;
• adding the optical supervisory signals in a high span loss optical fiber span;
• extracting the optical supervisory signals from the high span loss optical fiber span;
• and
• amplifying the optical supervisory signals, thereby increasing a signal-to-noise ratio of the optical supervisory signals.

A method of propagating optical supervisory signals in a high-span loss optical fiber span, the method comprising:

• generating optical supervisory signals;
• adding the optical supervisory signals in a high span loss optical fiber span;
• extracting the optical supervisory signals from the high span loss optical fiber span;
• and
• filtering at least one of amplified spontaneous emissions, a Raman optical pumping signal that amplifies the optical supervisory signals, Raman optical pumping signals that amplify optical data signals, and optical data signals from the optical supervisory signals, thereby increasing a signal-to-noise ratio of the optical supervisory signals.

A method of propagating optical supervisory signals in a high-span loss optical fiber span, the method comprising:

• generating optical supervisory signals;
• encoding the optical supervisory signals;
• adding the encoded optical supervisory signals to a high span loss optical fiber span;
• extracting the encoded optical supervisory signals from the high span loss optical fiber span;
• and
• decoding the extracting encoded optical supervisory signals, thereby correcting transmission errors in the optical supervisory signals.