ALEXANDRIA, Va., Feb. 17 -- United States Patent no. 12,556,285, issued on Feb. 17, was assigned to NTT Inc. (Tokyo).
"Optical transmitter and frequency control method in optical transmission" was invented by Ryo Igarashi (Musashino, Japan), Masamichi Fujiwara (Musashino, Japan) and Junichi Kani (Musashino, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "An optical transmission apparatus includes an optical transmitter that generates an optical signal in an uplink direction by modulating output light of a laser that outputs light of a first frequency with a subcarrier on which transmission data is superimposed, a heterodyne detection unit that receives an optical signal in a downlink direction by hetero...