Hybrid brillouin/erbium doped fiber amplifier apparatus and method

An apparatus for use in fiber optic transmission systems, said apparatus comprising:

• a coherent light source;
• an erbium-doped fiber amplifier (EDFA) for amplifying light received from the light source in a first optical path;
• a phase modulator for modulating light received from said optical source in a second optical path;
• a circulator receiving amplified optical signals from said EDFA;
• an optical fiber for receiving optical signals at one end thereof from said circulator, an opposite end of said fiber receiving modulated optical signals from said phase modulator, said optical fiber and said circulator being used for Brillouin amplification of optical signals;
• and
• a detector for detecting optical signals output from said circulator.

A method for modulating optical signals in analog photonic links, said method comprising:

• amplifying light received in a first optical path from an optical source using an erbium-doped fiber amplifier (EDFA);
• phase-modulating light received in a second optical path from said optical source using a phase modulator;
• receiving amplified optical signals from said EDFA in a circulator;
• receiving amplified optical signals from said circulator into a first end of said optical fiber;
• passing phase-modulated optical signals from said phase modulator into an opposite second end of said optical fiber;
• and
• detecting output signals from said circulator.

An apparatus for use in fiber optic transmission systems, said apparatus comprising:

• a coherent laser source;
• a coupler receiving input light from the laser source for splitting input light into first and second optical paths;
• an erbium-doped fiber amplifier (EDFA) disposed in said first optical path, said EDFA receiving input light from said coupler and amplifying the input light;
• a fiber-optic circulator receiving said amplified input signals from said EDFA and supplying output signals from one port of said circulator to a first end of an optical fiber;
• a phase modulator disposed in said second optical path for modulating the input light prior to forwarding the input light into a second opposite end of the optical fiber;
• and

A method for light amplification and noise reduction in fiber optic communication links, said method comprising:

• providing a coherent laser source;
• amplifying light received from the laser source in a first optical path by an erbium-doped fiber amplifier (EDFA);
• receiving light from the EDFA in a circulator;
• feeding output signals from said circulator into a first end of an optical fiber;
• modulating, at Brillouin frequency, light received from the laser source in a second optical path using a phase modulator;
• feeding the modulated light into an opposite second end of the optical fiber;
• and
• detecting the output of said circulator.

A hybrid amplifier for use in fiber optic communication links, said amplifier comprising:

• a coherent laser source;
• an erbium-doped fiber amplifier(EDFA) for amplifying optical signals;
• a circulator in combination with an optical fiber used as a Brillouin amplifier;
• and
• a phase modulator for providing seed input to the Brillouin amplifier.

An apparatus for filtering noise in fiber optic communication links, said apparatus comprising:

• a laser source;
• an amplifier disposed in a first optical path, said amplifier receiving light from said laser source;
• a circulator receiving light from amplifier and producing output signals, the output signals being fed into a first end of an optical fiber, a second opposite end of the fiber receiving light from said laser source in a second optical path;
• and
• a detector for detecting output of said circulator.