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US 6,310,717 B1Granted
Optical amplifier and fiber module for optical amplification
AssigneeFujitsu Limited
InventorsNorihisa Naganuma, Norifumi Shukunami
Life of this patent
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Abstract
Disclosed herein is an optical amplifier reduced in gain deviation. The optical amplifier includes a nonsilica fiber doped with a rare earth, and a fiber holder in which the nonsilica fiber is inserted and fixed. The fiber holder is optically arranged so that signal light to be amplified propagates in the nonsilica fiber. The nonsilica fiber is pumped so that the nonsilica fiber provides a gain band including the wavelength of the signal light. Opposite ends of the fiber holder are hermetically sealed to thereby easily cut off the nonsilica fiber from the outside air, so that the nonsilica fiber is stabilized physically or chemically. A fluoride glass fiber is suitable for the nonsilica fiber to reduce the gain deviation in a 1.55 μm band.
Claims31
An optical amplifier comprising:
- a nonsilica fiber doped with a rare earth element;
- a fiber holder having a first end portion, a second end portion, and a hole extending between said first end portion and said second end portion, said nonsilica fiber being inserted and fixed in said hole;
- sealing means for hermetically sealing said first end portion and said second end portion of said fiber holder;
- optical means optically connected to said first end portion and said second end portion so that signal light to be amplified propagates in said nonsilica fiber;
- and
- means for pumping said nonsilica fiber so that said nonsilica fiber provides a gain band including the wavelength of said signal light,
- said nonsilica fiber comprising a first nonsilica fiber having a first end and a second end respectively corresponding to said first end portion and said second end portion of said fiber holder, and a second nonsilica fiber having a third end and a fourth end respectively corresponding to said first end portion and said second end portion of said fiber holder.
4 more elements
An optical amplifier comprising:
- a nonsilica fiber doped with a rare earth element;
- a fiber holder having a first end portion, a second end portion, and a hole extending between said first end portion and said second end portion, said nonsilica fiber being inserted and fixed in said hole;
- sealing means for hermetically sealing said first end portion and said second end portion of said fiber holder;
- optical means optically connected to said first end portion and said second end portion so that signal light to be amplified propagates in said nonsilica fiber;
- and
- means for pumping said nonsilica fiber so that said nonsilica fiber provides a gain band including the wavelength of said signal light,
- said sealing means comprising antireflection films formed on said first end portion and said second end portion of said fiber holder so as to cover end faces of said nonsilica fiber.
4 more elements
An optical amplifier comprising:
- a nonsilica fiber doped with a rare earth element;
- a fiber holder having a first end portion, a second end portion, and a hole extending between said first end portion and said second end portion, said nonsilica fiber being inserted and fixed in said hole;
- sealing means for hermetically sealing said first end portion and said second end portion of said fiber holder;
- optical means optically connected to said first end portion and said second end portion so that signal light to be amplified propagates in said nonsilica fiber;
- and
- means for pumping said nonsilica fiber so that said nonsilica fiber provides a gain band including the wavelength of said signal light;
- said optical means comprising first and second lenses respectively opposed to said first end portion and said second end portion of said fiber holder;
- said optical amplifier further comprising a first sleeve in which said first lens and said first end portion of said fiber holder are inserted, and a second sleeve in which said second lens and said second end portion of said fiber holder are inserted;
- whereby hermetic sealing of said first end portion and said second end portion of said fiber holder by said sealing means is enhanced.
6 more elements
An optical amplifier comprising:
- a nonsilica fiber doped with a rare earth element;
- a fiber holder having a first end portion, a second end portion, and a hole extending between said first end portion and said second end portion, said nonsilica fiber being inserted and fixed in said hole;
- sealing means for hermetically sealing said first end portion and said second end portion of said fiber holder;
- optical means optically connected to said first end portion and said second end portion so that signal light to be amplified propagates in said nonsilica fiber;
- and
- means for pumping said nonsilica fiber so that said nonsilica fiber provides a gain band including the wavelength of said signal light;
- said nonsilica fiber comprising a first nonsilica fiber having a first end and a second end respectively corresponding to said first end portion and said second end portion of said fiber holder, and a second nonsilica fiber having a third end and a fourth end respectively corresponding to said first end portion and said second end portion of said fiber holder;
- and
- said rare earth element being selected from the group consisting of Er (erbium), Pr (praseodymium), and Nd (neodymium).
6 more elements
An optical amplifier comprising:
- a nonsilica fiber doped with a rare earth element;
- a fiber holder having a first end portion, a second end portion, and a hole extending between said first end portion and said second end portion, said nonsilica fiber being inserted and fixed in said hole;
- sealing means for hermetically sealing said first end portion and said second end portion of said fiber holder;
- optical means optically connected to said first end portion and said second end portion so that signal light to be amplified propagates in said nonsilica fiber;
- and
- means for pumping said nonsilica fiber so that said nonsilica fiber provides a gain band including the wavelength of said signal light;
- said nonsilica fiber comprising a first nonsilica fiber having a first end and a second end respectively corresponding to said first end portion and said second end portion of said fiber holder, and a second nonsilica fiber having a third end and a fourth end respectively corresponding to said first end portion and said second end portion of said fiber holder;
- and
- said nonsilica fiber being selected from the group consisting of a fluoride glass fiber and a tellurite glass fiber.
6 more elements
An optical amplifier comprising:
- a nonsilica fiber doped with a rare earth element;
- a fiber holder having a first end portion, a second end portion, and a hole extending between said first end portion and said second end portion, said nonsilica fiber being inserted and fixed in said hole;
- sealing means for hermetically sealing said first end portion and said second end portion of said fiber holder;
- optical means optically connected to said first end portion and said second end portion so that signal light to be amplified propagates in said nonsilica fiber;
- and
- means for pumping said nonsilica fiber so that said nonsilica fiber provides a gain band including the wavelength of said signal light;
- said nonsilica fiber comprising a first nonsilica fiber having a first end and a second end respectively corresponding to said first end portion and said second end portion of said fiber holder, and a second nonsilica fiber having a third end and a fourth end respectively corresponding to said first end portion and said second end portion of said fiber holder;
- and
- the doping concentration of said rare earth element being 50,000 ppm or more, so that the length of said nonsilica fiber is reduced sufficiently in practical use.
6 more elements
An optical amplifier according to claim 17, wherein:
- each of said first and second polarization beam combiners comprises a birefringent prism.
An optical amplifier comprising:
- a first optical waveguide structure doped with a rare earth element and having a first end and a second end;
- a second optical waveguide structure doped with a rare earth element and having a third end and a fourth end respectively corresponding to said first end and said second end;
- a first lens opposed to said first end and said third end;
- a second lens opposed to said second end and said fourth end;
- first and second pump light sources for respectively outputting first and second pump light beams;
- and
- a reflector provided near a focal point of said second lens for coupling said second end of said first optical waveguide structure and said fourth end of said second optical waveguide structure by reflection of signal light;
- said first pump light beam being supplied through said reflector and said second lens to said second end of said first optical waveguide structure;
- said second pump light beam being supplied through said reflector and said second lens to said fourth end of said second optical waveguide structure;
- said first end of said first optical waveguide structure and said third end of said second optical waveguide structure being coupled through said first lens to an input port and an output port for said signal light, respectively.
7 more elements
A fiber module for optical amplification, comprising:
- a nonsilica fiber doped with a rare earth element;
- a fiber holder having a first end portion, a second end portion, and a hole extending between said first end portion and said second end portion, said nonsilica fiber being inserted and fixed in said hole;
- and
- sealing means for hermetically sealing said first end portion and said second end portion of said fiber holder, said sealing means comprising
- antireflection films formed on said first end portion and said second end portion of said fiber holder so as to cover end faces of said nonsilica fiber.
2 more elements
A fiber module for optical amplification, comprising:
- a nonsilica fiber doped with a rare earth element;
- a fiber holder having a first end portion, a second end portion, and a hole extending between said first end portion and said second end portion, said nonsilica fiber being inserted and fixed in said hole;
- and
- sealing means for hermetically sealing said first end portion and said second end portion of said fiber holder, wherein
- each of said first end portion and said second end portion of said fiber holder is polished substantially spherically;
- said sealing means comprises first and second fiber assemblies respectively abutting against said first end portion and said second end portion of said fiber holder;
- and
- each of said first and second fiber assemblies comprises a silica fiber and a ferrule having a hole in which said silica fiber is inserted and fixed.
5 more elements
A fiber module for optical amplification, comprising:
- a nonsilica fiber doped with a rare earth element;
- a fiber holder having a first end portion, a second end portion, and a hole extending between said first end portion and said second end portion, said nonsilica fiber being inserted and fixed in said hole;
- first and second lenses respectively opposed to said first end portion and said second end portion of said fiber holder;
- a first sleeve in which said first lens and said first end portion of said fiber holder are inserted;
- and
- a second sleeve in which said second lens and said second end portion of said fiber holder are inserted.
3 more elements
An apparatus comprising:
- a nonsilica fiber doped with a rare earth element;
- a fiber holder having a first end portion, a second end portion, and a hole extending between said first end portion and said second end portion, said nonsilica fiber being inserted and fixed in said hole;
- sealing means for hermetically sealing said first end portion and said second end portion of said fiber holder;
- and
- means for pumping said nonsilica fiber so that said nonsilica fiber provides a gain band,
- said nonsilica fiber comprising a first nonsilica fiber having a first end of a second end respectively corresponding to said first end portion and said second end portion of said fiber holder, and a second nonsilica fiber having a third end and a fourth end respectively corresponding to said first end portion and said second end portion of said fiber holder.
3 more elements
Dependencies are inferred from the claim text.