US 11,888,281 B2
Multimode optical amplifier
Hirotaka Ono, Musashino (JP); Takayuki Mizuno, Musashino (JP); Koki Shibahara, Musashino (JP); and Yutaka Miyamoto, Musashino (JP)
Assigned to NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo (JP)
Appl. No. 17/252,443
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed Jul. 12, 2019, PCT No. PCT/JP2019/027672
§ 371(c)(1), (2) Date Dec. 15, 2020,
PCT Pub. No. WO2020/017446, PCT Pub. Date Jan. 23, 2020.
Claims priority of application No. 2018-136139 (JP), filed on Jul. 19, 2018.
Prior Publication US 2021/0257802 A1, Aug. 19, 2021
Int. Cl. H01S 3/067 (2006.01); H01S 3/00 (2006.01); H01S 3/16 (2006.01)
CPC H01S 3/06716 (2013.01) [H01S 3/0078 (2013.01); H01S 3/1608 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A multimode optical amplifier that provides gain to a plurality of propagation modes of signal light, the multimode optical amplifier comprising:
a multiplexer that multiplexes the signal light and excitation light;
an amplifying fiber which has a core that propagates a predetermined plurality of propagation modes of the signal light and a predetermined plurality of propagation modes of the excitation light, and which provides an individual gain value for each of the predetermined propagation modes of the signal light;
a wavelength-flattening filter that maintains a constant gain value for a frequency for all predetermined propagation modes of the signal light; and
a mode-flattening filter that maintains the gain value at a constant value for a predetermined propagation mode of the signal light for all predetermined propagation modes of the signal light.