US 12,483,333 B2
Optical transmitter
Shigeru Kanazawa, Musashino (JP); Yasuhiko Nakanishi, Musashino (JP); Takahiko Shindo, Musashino (JP); and Meishin Chin, Musashino (JP)
Assigned to NTT, INC., Tokyo (JP)
Appl. No. 18/258,396
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed Jan. 7, 2021, PCT No. PCT/JP2021/000324
§ 371(c)(1), (2) Date Jun. 20, 2023,
PCT Pub. No. WO2022/149235, PCT Pub. Date Jul. 14, 2022.
Prior Publication US 2024/0322910 A1, Sep. 26, 2024
Int. Cl. H04B 10/50 (2013.01); G02B 6/293 (2006.01); G02B 6/42 (2006.01)
CPC H04B 10/506 (2013.01) [G02B 6/4215 (2013.01); G02B 6/4286 (2013.01); G02B 6/29367 (2013.01); G02B 6/2938 (2013.01)] 3 Claims
OG exemplary drawing
 
1. An optical transmitter that multiplexes and outputs a plurality of wavelength channels, the optical transmitter comprising:
a first light source;
at least one second light source having a different wavelength from the first light source, the at least one second light source each having a different wavelength;
a plurality of collimator lenses coupled to respective outputs of the first light source and the second light source;
an optical multiplexer that causes an output light beam from the first light source to be transmitted from a first end surface to a second end surface facing the first end surface, causes the output light beam from the first light source to be reflected by a reflecting mirror formed on the second end surface, causes an output light beam from the second light source to pass through a wavelength filter formed on the first end surface, causes the output light beam from the second light source to be reflected by the reflecting mirror, and causes output light beams of the respective wavelength channels to reciprocate between the reflecting mirror and the wavelength filter, to sequentially multiplex the output light beams of the respective wavelength channels;
a plurality of beam splitters respectively inserted between the plurality of collimator lenses and the first end surface, the beam splitters each having an antireflective film formed in a region corresponding to a maximum diameter of a parallel light beam collimated by the collimator lens, and a reflective film being formed on the same surface as the antireflective film, in a peripheral region, other than the region corresponding to the maximum diameter of the parallel light beam; and
a plurality of monitor PDs that monitor optical powers branched from the respective beam splitters of the plurality of beam splitters.