US 7,127,139 B2Granted

Optical multiplexing method and optical multiplexer, and optical amplifier using same

AssigneeFujitsu Limited

InventorsMiki Onaka, Etsuko Hayashi, Hiroshi Onaka

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Abstract

An object of the invention is to provide an optical multiplexing method and an optical multiplexer, capable of fixing lights of different wavelengths at required wavelengths to stably multiplex them with a simple optical circuit configuration. To this end, in the present optical multiplexer, there is provided a tilted FBG, which is formed on an optical fiber through which a first light is propagated, with a grating direction thereof being tilted to an axial direction of the optical fiber, and has the sufficiently high reflectance to a second light (multiplexed light) of a wavelength different from that of the first light. The multiplexed light emitted from a light source is irradiated to the tilted FBG, via a free space from an angle direction determined according to a grating pitch of the tilted FBG and the wavelength of the multiplexed light, to be coupled within the optical fiber. Further, a low reflective FBG reflecting light coupled within the optical fiber is formed on the optical fiber, to achieve a resonance structure between the low reflective FBG and the light source, thereby stabling the wavelength of the multiplexed light.

Claims20

Dependent claims

An optical multiplexer, in which a first light being propagated through an optical fiber is multiplexed with a second light having a wavelength different from that of said first light, comprising:

a first fiber Bragg grating, which has transmission wavelength characteristics to transmit said first light and to reflect said second light, and is formed on said optical fiber with a grating direction thereof being tilted to an axial direction of said optical fiber;
a light source irradiating lights containing a wavelength component of said second light to said first fiber Bragg grating from an angle direction determined according to a grating pitch of said first fiber Bragg grating and the wavelength of said second light;
and
a second fiber Bragg grating, which has the reflectance lower than the reflectance of said first fiber Bragg grating relative to said second light and has a grating plane perpendicular to the axial direction of said optical fiber, and is formed on said optical fiber on the side where said second light irradiated from said light source to said first fiber Bragg grating and coupled within said optical fiber is propagated,
wherein said second light is resonated between said light source and said second fiber Bragg grating via said first fiber Bragg grating;
and
wherein said light source irradiates a light obtained by polarizingly combining a plurality of lights in different polarization states to said first fiber Bragg grating.

4 more elements

An optical amplifier, in which supplies a pumping light to an amplification medium, to perform the optical amplification on a signal light being propagated through said amplification medium, comprising:

a first fiber Bragg grating, which has transmission wavelength characteristics to transmit said signal light and to reflect said pumping light, and is formed on an optical fiber connected to said amplification medium with a grating direction thereof being tilted to an axial direction of said optical fiber;
a pumping light source irradiating lights containing a wavelength component of said pumping light to said first fiber Bragg grating from an angle direction determined according to a grating pitch of said first fiber Bragg grating and the wavelength of said pumping light;
and
a second fiber Bragg grating, which has the reflectance lower than the reflectance of said first fiber Bragg grating relative to said pumping light and has a grating plane perpendicular to the axial direction of said optical fiber, and is formed on said optical fiber on the side where said pumping light emitted from said pumping light source, and irradiated to said first fiber Bragg grating and coupled within said optical fiber is propagated,
wherein said pumping light is resonated between said pumping light source and said second fiber Bragg grating via said first fiber Bragg grating.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/878,619Filed 29 Jun 2004
Priority: JP 2004-04773924 Feb 2004
Published: US 2005/0185885 A125 Aug 2005
Granted: 24 Oct 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

H01S 3/302
Using scattering effects, e.g. stimulated Brillouin or Raman effects: in an optical fibre
G02B 6/29319
Light guides of the optical fibre type: with a cascade of diffractive elements or of diffraction operations
G02B 6/2938
Characterised by the function or use of the complete device: for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g.…
H04B 10/291
Repeaters: in which processing or amplification is carried out without conversion of the main signal from optical form