Optical fiber amplifier and dispersion compensating fiber module for optical fiber amplifier

An apparatus, comprising:

• means for receiving from an optical fiber a WDM optical signal traveling in the optical fiber in a first direction;
• means for amplifying the received WDM optical signal;
• and,
• means for outputting a pumping light to the optical fiber, said pumping light traveling in the optical fiber in a second direction opposite to the first direction, and causing amplification of the WDM optical signal by Stimulated Raman Scattering in the optical fiber with a first gain of reduced polarization dependency.

An apparatus comprising:

• an optical device for receiving from an optical fiber an optical signal including a plurality of optical signals with different wavelengths and traveling in the optical fiber in a first direction;
• a pumping light source outputting a pumping light to the optical fiber so that the pumping light travels in the optical fiber in a second direction and causing the optical signal to be amplified by Stimulated Raman Scattering in the optical fiber with a first gain of reduced polarization dependency;
• and,
• an optical amplifier, further amplifying the Raman amplified optical signal with a second gain.

An apparatus for coupling to an optical fiber, comprising:

• means for outputting a pumping light to the optical fiber causing amplification of an optical signal, the optical signal traveling in the optical fiber in a first direction;
• and,
• means for further amplifying the amplified optical signal, wherein
• the pumping light traveling in the optical fiber in a second direction and the optical signal is amplified by Stimulated Raman Scattering in the optical fiber with a first gain of reduced polarization dependency.

An optical amplifying apparatus, comprising:

• means for outputting a pumping light to an optical fiber which causes a WDM optical signal to be amplified, the WDM optical signal traveling in the optical fiber in a first direction;
• means for receiving the amplified WDM optical signal from the optical fiber;
• and,
• means for further amplifying the received amplified WDM optical signal, wherein
• the pumping light travels in the optical fiber in a second direction opposite to the first direction and the WDM optical signal is amplified by Stimulated Raman Scattering in the optical fiber with a first gain of reduced polarization dependency.

A method of amplifying a WDM optical signal, comprising:

• transmitting the WDM optical signal through an optical fiber in a first direction;
• outputting a pumping light to an optical fiber, the pumping light traveling in the optical fiber in a second direction and causing the WDM optical signal to be amplified by Stimulated Raman Scattering with a first gain of reduced polarization dependency;
• coupling the Raman amplified WDM optical signal to an optical amplifier;
• and,
• further amplifying the Raman amplified WDM optical signal by the optical amplifier.