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:
Nov. 12, 1996
Filed:
Oct. 24, 1995
Ando Electric Co., Ltd., Tokyo, JP;
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Abstract
A noise determination apparatus for simple and precise determination of a noise factor of an optical fiber amplifier is presented. An optical pulse Pin is inputted via an optical coupler 2 into an optical looping circuit 14, and for every loop around the circuit 14, the spontaneous emission light generated in a rare-earth doped optic fiber amplifier 4 is integrated. The amplitude of the light intensity of the optical pulse train outputted from the optical splitter 3 decreases as the looping cycles are increased, and ultimately, the light intensity of the accumulated spontaneous emission light becomes equal to that of the optical pulse train. The pulse train outputted from the photodetector 7 diminishes. The number of pulses in the looping process from the initial pulse train to the expiration event are counted by means of a pulse counting device 8. Based on the count, the noise factor NF of the optical amplifier 4 is calculated using the gain of the optical amplifier 4, the bandwidth of the bandpass filter 5, oscillation frequency of light and the pulse intensity.