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:
Jul. 06, 2021
Filed:
Sep. 18, 2020
Fujitsu Limited, Kawasaki, JP;
FUJITSU LIMITED, Kawasaki, JP;
Abstract
Embodiments of this disclosure provide a method and apparatus for monitoring a modulation depth of a dither signal and an optical transmitter. The apparatus includes a detector to detect an optical signal output by a Mach-Zehnder modulator to obtain an electrical signal, a dither signal at a determined frequency is superimposed on a direct current bias voltage of the Mach-Zehnder modulator; a frequency-doubling dither signal synchronization detection module to perform synchronization detection on the electrical signal and a frequency-doubling dither signal at a frequency twice the determined frequency, to obtain an amplitude of a signal component contained in the electrical signal at a frequency identical to the frequency of the frequency-doubling dither signal A signal processor is to calculate a modulation depth of the dither signal superimposed on the direct current bias voltage according to the amplitude of the signal component at the frequency identical to the frequency of the frequency-doubling dither signal.