The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 27, 2017
Filed:
Sep. 11, 2014
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Toshiya Matsuda, Tokyo-to, JP;
Fukutaro Hamaoka, Tokyo-to, JP;
Akira Naka, Tokyo-to, JP;
Kohei Saito, Tokyo-to, JP;
Nippon Telegraph And Telephone Corporation, Tokyo, JP;
Abstract
A receiver is configured to have two coherent receivers using two pieces of local oscillator of optical frequencies fand fclose to optical frequency fof signal light, the two pieces of local oscillator being controlled to have a predetermined optical frequency spacing ΔF, and a digital signal processor demodulating transmission data signal sequences based on outputs from the coherent receivers. When the frequency difference Δfof one of the two pieces of local oscillator from a virtual reference frequency f' close to the optical frequency fof the signal light is set, the digital signal processor obtains the frequency difference Δfof the other of the two pieces of local oscillator by calculating Δf−ΔF, inputs electric signals output from the two coherent receivers, and compensates the phase rotation caused in the electric signals by frequency differences Δfand Δf