Complex rare-earths doped optical waveguide

Details Complex rare-earths doped optical waveguide Complex rare-earths doped optical waveguide

2000-02-04

2002-10-01

Ullah, Akm E. (Department: 2874)

Optical waveguides

Having particular optical characteristic modifying chemical...

Of waveguide core

Reexamination Certificate

active

06459846

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a complex rare-earths doped optical waveguide. In particular, the complex rare-earths doped optical waveguide in accordance with an embodiment of the present invention is for modifying emission spectrum of erbium that is able to significantly enhance optical gain from shorter wavelength than 1530 nm.
BACKGROUND OF THE INVENTION
Wavelength division multiplexing method has been studied as a core technology for satisfying increasing demand in the area of optical communication networks. Likewise, optical amplifiers with broadband gain are needed.
Currently, gain wavelength of erbium doped silica optical amplifier is fixed over 1530 nm. Also, in order to amplify other wavelength regions, optical gain is obtained at ~1300 nm, ~1470 nm, and ~1650 nm by employing praseodymium (Pr) ion and thulium (Tm) ion, respectively.
Erbium ion is an efficient gain medium. Since erbium results in a conspicuous gain when configured to optical fiber amplifiers regardless of host compositions of the optical fibers, many studies have been performed to obtain gain at shorter wavelength than 1530 nm by employing erbium ion.
When erbium ion dopes a crystal or a glass, it is excited by light or electricity and as a result, fluorescent emission in 1460~1650 nm is evident, which is from
4
I
13/2
→
4
I
15/2
transition.
Gain wavelength of conventional erbium doped optical fiber amplifiers is between 1530 nm and 1600 nm and it is difficult for conventional erbium doped optical fiber amplifiers to obtain gain at wavelength shorter than 1530 nm. It is because that the emission cross-section of
4
I
13/2
→
4
I
15/2
transition is small at wavelength shorter than 1530 nm.
Generally, spectral lineshape of a gain spectrum is similar to shape of the amplified spontaneous emission spectrum, it is difficult for conventional erbium doped optical fiber amplifiers to obtain gain at wavelength shorter than 1530 nm.
SUMMARY OF THE INVENTION
A complex rare-earths doped optical waveguide is provided. The complex rare-earths doped optical waveguide in accordance with an embodiment of the present invention includes clad and core. The core is doped with erbium (Er) ion. The interior or exterior region of the core is doped with at least one of complex rare-earth ions. The interior and (or) the exterior region of the core, where the rare-earth ion (s) dope (s), is at a certain distance apart from the erbium-doped region.
Preferably, the complex rare-earth ion is thulium (Tm), terbium (Tb), dysprosium (Dy), or neodymium (Nd).
Preferably, erbium (Er) is doped within certain length from center of the core.
Preferably, the interior and (or) exterior of the core is doped with at least one complex rare-earth ion.
Preferably, a layer doped with at least one complex rare-earth ion wraps the erbium-doped layer of the core.
Preferably, distance between the erbium doped layer and the complex rare-earths doped layer is farther than 20 nm.
A complex rare-earths doped optical waveguide is provided. The. complex rare-earths doped optical waveguide in accordance with an embodiment of the present invention includes clad and core. In the whole region or in a fraction of the core are doped combination of erbium (Er) ion and ytterbium (Yb) ion. A layer, a certain distance apart from the erbium/ytterbium-doped layer is introduced and the layer is doped with at least one complex rare-earth ion.
Preferably, the complex rare-earth ion is thulium (Tm), terbium (Tb), dysprosium (Dy), or neodymium (Nd).
Preferably, erbium (Er) and ytterbium (Yb) are codoped in the core.
Preferably, the internal or the surface of the core is doped with at least one complex rare-earths ion.
Preferably, the internal or the surface of the core is wrapped by at least one complex rare-earths ion.
Preferably, distance between the erbium (Er) and ytterbium (Yb) codoped layer and the complex rare-earths doped layer is farther than 20 nm.
A complex rare-earths doped optical waveguide is provided. The complex rare-earths doped optical waveguide in accordance with an embodiment of the present invention includes clad and core. The core is doped with erbium (Er) ion and part of the clad is doped with at least one complex rare-earths ion.
Preferably, the complex rare-earths ion is thulium (Tm), terbium (Tb), dysprosium (Dy), or neodymium (Nd).
A complex rare-earths doped optical waveguide is provided. The complex rare-earths doped optical waveguide in accordance with an embodiment of the present invention includes clad and core. The core is doped with combination of erbium (Er) ion and ytterbium (Yb) ion and part of the clad is doped with at least one complex rare-earths ion. A complex rare-earths doped layer is introduced apart a certain distance from the core, in the clad region.
Preferably, the complex rare-earths ion is thulium (Tm), terbium (Tb), dysprosium (Dy), or neodymium (Nd).


REFERENCES:
patent: 4923279 (1990-05-01), Ainslie et al.
patent: 5274734 (1993-12-01), Jin et al.
patent: 5668659 (1997-09-01), Sakamoto et al.
patent: 6122429 (2000-09-01), Wessels et al.
patent: 6151429 (2000-11-01), Kristensen et al.
patent: 6226308 (2001-05-01), Samson et al.
patent: 6288835 (2001-09-01), Nilsson et al.
Ainslie et al., “The Absorption and Fluorescence Spectra of Rare Earth Ions in Silica-Based Monomode Fibre,”Journal of Lightwave Technology, 6(2):287-293, Feb., 1988.
Diggonet, “Closed Form Expressions for the Gain in Three-and Four-Level Laser Fibers,”IEEE Journal of Quantum Electronics, 26(10):1788-1796, Oct., 1990.
Sakamoto et al., “35-dB Gain Tm-Doped ZBLYAN Fiber Amplifier Operting at 1.65 um,”IEEE Photonics Technology Letters, 8(3):349-351, Mar., 1996.

Affiliated with

Also associated with

Rating

Complex rare-earths doped optical waveguide does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Complex rare-earths doped optical waveguide, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Complex rare-earths doped optical waveguide will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2998398