US 12,438,330 B2
Optical device and fiber laser apparatus
Yasuhiro Mashiko, Sakura (JP); Shinichi Sakamoto, Sakura (JP); and Sho Namiki, Sakura (JP)
Assigned to Fujikura Ltd., Tokyo (JP)
Appl. No. 17/792,295
Filed by Fujikura Ltd., Tokyo (JP)
PCT Filed Feb. 19, 2021, PCT No. PCT/JP2021/006361
§ 371(c)(1), (2) Date Jul. 12, 2022,
PCT Pub. No. WO2021/210267, PCT Pub. Date Oct. 21, 2021.
Claims priority of application No. 2020-072971 (JP), filed on Apr. 15, 2020.
Prior Publication US 2023/0344187 A1, Oct. 26, 2023
Int. Cl. H01S 3/067 (2006.01); H01S 3/091 (2006.01)
CPC H01S 3/06708 (2013.01) [H01S 3/091 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An optical device comprising:
a first fiber including a first reflector;
a second fiber including a second reflector; and
an amplifying fiber that has a normalized frequency that is greater than or equal to 5.13 and is wound so as not to intersect on one plane and including:
an outer section wound in a circular manner;
an inner section having first arc portions and wound such that at least two of the first arc portions have a radius of curvature in which a higher-order mode that is higher than an LP11 mode has loss;
a first end connected to the first fiber and disposed on an inside of the amplifying fiber; and
a second end connected to the second fiber.