| US 7,492,993 B2 | ||
| Multi-port coupler, optical amplifier, and fiber laser | ||
| Michihiro Nakai, Sakura (Japan); and Tetsuya Sakai, Sakura (Japan) | ||
| Assigned to Fujikura Ltd., Tokyo (Japan) | ||
| Filed on May 30, 2007, as Appl. No. 11/755,681. | ||
| Claims priority of application No. 2006-149696 (JP), filed on May 30, 2006; and application No. 2006-260881 (JP), filed on Sep. 26, 2006. | ||
| Prior Publication US 2007/0280597 A1, Dec. 06, 2007 | ||
| Int. Cl. G02B 6/26 (2006.01) | ||
| U.S. Cl. 385—46 [385/15; 385/31; 385/39] | 13 Claims |
| 1. A multi-port coupler for coupling a pumping light source to a cladding pump fiber for optical amplification, comprising:
a central signal fiber and a plurality of pumping fibers arranged around the central signal fiber, the central signal fiber
and the plurality of pumping fibers being unified and a front side is reduced in diameter,
wherein an emitted light confining waveguide part is provided around a core of the signal fiber located at the center, and
the emitted light confining waveguide part whose outer diameter is larger than that of the core has a higher refractive index
than a cladding and a lower refractive index than the core and the emitted light confining waveguide part is formed continuously
from a splicing point of the cladding pump fiber to a coupler front end branched into multiple fibers.
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