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:
Sep. 12, 2017
Filed:
Aug. 20, 2014
Nec Corporation, Tokyo, JP;
Hirokazu Komatsu, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
In order to reduce a delay at the time of detecting inputted optical signals in an optical receiver using a variable optical attenuator, the optical receiver includes: a variable optical attenuator that outputs optical signals by attenuating the intensity of inputted optical signals; a photoelectric converter that converts the optical signals into electric signals; an amplitude detection circuit that outputs an output voltage based on the amplitude of the electric signals; an optical attenuator control circuit that outputs signals for controlling an attenuation quantity of the variable optical attenuator based on the output voltage; a signal detection circuit that outputs signal detection output by comparing the output voltage and a signal detection threshold voltage, i.e., reference of signal detection, to each other; and a threshold control circuit, which monitors the output voltage, and which changes the signal detection threshold voltage when an output voltage change state becomes stable with time.