Raman excitation control method and optical transmission system using the same

A Raman excitation control system comprising:

• a back power monitor circuit detecting backward lights produced by, and output in a backward direction from, a laser diode circuit producing Raman excitation light provided to an optical transmission line to thereby cause Raman amplification to occur in the optical transmission line;
• and
• a control circuit controlling light emission power of the Raman excitation light produced by the laser diode circuit according to level of the backward lights detected by the back power monitor circuit.

A method of controlling a laser diode producing excitation light provided to an optical transmission line to cause Raman amplification to occur in the optical transmission line, the method comprising:

• controlling the laser diode in accordance with a level of backward light produced by, and output in a backward direction from, the laser diode, to control light emission power of the excitation light produced by the laser diode.

An apparatus for controlling a laser diode producing excitation light provided to an optical transmission line to cause Raman amplification to occur in the optical transmission line, the apparatus comprising:

• a controller controlling the laser diode in accordance with a level of backward light produced by, and output in a backward direction from, the laser diode, to control light emission power of the excitation light produced by the laser diode.

An apparatus comprising:

• a laser diode producing excitation light provided to an optical transmission line to cause Raman amplification to occur in the optical transmission line;
• and
• means for controlling the laser diode in accordance with a level of backward light produced by, and output in a backward direction from, the laser diode, to control light emission power of the excitation light produced by the laser diode.

A method comprising:

• detecting backward light produced by, and output in a backward direction from, a laser diode producing excitation light provided to an optical transmission line to cause Raman amplification to occur in the optical transmission line;
• and
• controlling the laser diode in accordance with a level of the detected backward light to control light emission power of the excitation light produced by the laser diode.

An apparatus comprising:

• a detector detecting backward light produced by, and output in a backward direction from, a laser diode producing excitation light provided to an optical transmission line to cause Raman amplification to occur in the optical transmission line;
• and
• a controller controlling the laser diode in accordance with a level of the detected backward light to control light emission power of the excitation light produced by the laser diode.

A method comprising:

• detecting backward lights produced by, and output in a backward direction from, laser diodes producing excitation lights provided to an optical transmission line to cause Raman amplification to occur in the optical transmission line;
• and
• controlling the laser diodes in accordance with levels of the detected backward lights to control light emission powers of the excitation lights produced by the laser diodes.

An apparatus comprising:

• a detector detecting backward lights produced by, and output in a backward direction from, laser diodes producing excitation lights provided to an optical transmission line to cause Raman amplification to occur in the optical transmission line;
• and
• a controller controlling the laser diodes in accordance with levels of the detected backward lights to control light emission powers of the excitation lights produced by the laser diodes.

An apparatus comprising:

• a detector detecting backward lights produced by, and output in a backward direction from, laser diodes producing excitation lights provided to an optical transmission line to cause Raman amplification to occur in the optical transmission line;
• and
• means for controlling the laser diodes in accordance with levels of the detected backward lights to control light emission powers of the excitation lights produced by the laser diodes.