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:
Oct. 01, 2024
Filed:
Jan. 08, 2020
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Osamu Moriwaki, Musashino, JP;
Takashi Saida, Musashino, JP;
Kenya Suzuki, Musashino, JP;
Takashi Go, Musashino, JP;
Manabu Oguma, Musashino, JP;
Yuichiro Ikuma, Musashino, JP;
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Abstract
A wavelength monitoring apparatus includes a wavelength monitoring circuit. The wavelength monitoring circuit includes: a split circuit that splits an input optical signal into two; an optical delay circuit that applies a delay time difference to the two split optical signals; and a two-input two-output optical multiplexer/demultiplexer circuit that outputs a result of applying multiplexing interference to the optical signals to which the delay time difference has been applied. The wavelength monitoring apparatus further includes photoelectric conversion elements that perform photoelectric conversions on the two optical signals output from the wavelength monitoring circuit so as to output electrical signals. The wavelength monitoring apparatus is configured to obtain the wavelength of the optical signal, by calculating a ratio between two electrical outputs of the photoelectric conversion elements and referring to a correspondence table indicating wavelengths of optical signals input to the wavelength monitoring circuit and ratios between electrical outputs.