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, 1996
Filed:
Oct. 13, 1995
Takashi Iwasaki, Tokyo, JP;
Haruyoshi Uchiyama, Tokyo, JP;
Kazuo Aida, Yokohama, JP;
Yoshiaki Sato, Chiba, JP;
Ando Electric Co., Ltd., Tokyo, JP;
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Abstract
A simple, quick and precise method for determining a noise factor of an optical amplifier system is presented and demonstrated with an apparatus based on rare-earth doped optical fibers. The method is based on rapid adjustments of the phase differentials between the input optical signals into and the output optical signals from the optical amplifier to compensate for system variables including the optical fiber lengths within the apparatus as well as in the ancillary devices. A cw laser source is modulated with a first pulse having a significantly shorter cycle than a lifetime of excited atoms within the doped fiber, and the modulated pulses are continually applied to the noise determining apparatus. The optical output signal from the apparatus is synchronized with the first pulse and the optical output signal is further modulated with a series of second pulses having increasing phase differentials in relation to the first pulse. The electrical output power from the noise determining apparatus undergoes a maximum and a minimum values, and the noise factor of the apparatus is calculated by using the values of the respective maximum and the minimum electrical output power.