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:
Mar. 19, 2013
Filed:
May. 14, 2009
Fumihiko Ito, Tsukuba, JP;
Keiji Okamoto, Tsukuba, JP;
Fumihiko Ito, Tsukuba, JP;
Keiji Okamoto, Tsukuba, JP;
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Abstract
Light to be measured L and sampling pulse light Lare each split into M beams, and a time delay of 0, T, 2T, . . . , (M−1)T is given to each of the M-split sampling pulse light beams. The M-split light beams to be measured are then respectively multiplexed with M optical 90-degree hybrids, and M electrical field amplitudes per time T are determined for the light beam to be measured, based on M sets of output currents received at a balance light receiving element that receives light emitted from each of the optical 90-degree hybrids. The amplitudes of the respective wavelength optical signals contained in the light beam to be measured are calculated through Fourier transformations of the field electrical amplitudes. Pulsed light with a spectral width that covers the total frequency bandwidth of the light to be measured is used as the sampling pulse light. Where the total frequency bandwidth of the light to be measured is Δf, and the frequency interval of the optical signals contained in the light to be measured is Δf, T≦1/Δfand 1/(MT)≦Δf are set.