US 12,288,962 B2
Optical transmitter
Takahiko Shindo, Musashino (JP); Meishin Chin, Musashino (JP); and Shigeru Kanazawa, Musashino (JP)
Assigned to Nippon Telegraph and Telephone Corporation, Tokyo (JP)
Appl. No. 17/760,662
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed Sep. 26, 2019, PCT No. PCT/JP2019/037956
§ 371(c)(1), (2) Date Mar. 15, 2022,
PCT Pub. No. WO2021/059447, PCT Pub. Date Apr. 1, 2021.
Prior Publication US 2022/0337026 A1, Oct. 20, 2022
Int. Cl. H01S 5/00 (2006.01); H01S 5/026 (2006.01); H01S 5/12 (2021.01); H01S 5/34 (2006.01); H01S 5/50 (2006.01); G02F 1/017 (2006.01); H01S 5/062 (2006.01); H01S 5/10 (2021.01); H04B 10/50 (2013.01)
CPC H01S 5/026 (2013.01) [H01S 5/0265 (2013.01); H01S 5/12 (2013.01); H01S 5/34 (2013.01); H01S 5/50 (2013.01); H01S 5/5027 (2013.01); G02F 1/01708 (2013.01); G02F 2203/70 (2013.01); H01S 5/06226 (2013.01); H01S 5/1014 (2013.01); H01S 5/1039 (2013.01); H04B 10/503 (2013.01)] 7 Claims
OG exemplary drawing
 
1. An optical transmitter comprising, on a substrate:
a distributed feedback (DFB) laser including an active region with a multi quantum well;
an electro-absorption (EA) modulator configured to modulate light emitted from the DFB laser; and
a semiconductor optical amplifier (SOA) having an active region with an identical composition as the active region of the DFB laser and configured to amplify signal light from the EA modulator,
wherein the SOA includes two or more electrically separated regions defined by contact layers disposed on the SOA along an optical waveguide direction, and a length in the optical waveguide direction of an N-th region (N is equal to or greater than 2) counting from an incidence end of the SOA is shorter than a length of the region located closer to the incidence end than the N-th region.