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. 23, 2008
Filed:
Dec. 10, 2007
Yasushi Koiwai, Kawasaki, JP;
Hiroki Kanesaka, Kawasaki, JP;
Yasushi Koiwai, Kawasaki, JP;
Hiroki Kanesaka, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
An apparatus is provided with a biasing unit supplying a bias signal to a first avalanche photodiode and a second avalanche photodiode, the bias signal having a first level and a second level, the first level causing a multiplying effect and the second level causing a non-multiplying effect for the first and the second avalanche photodiodes; a smoothing unit smoothing the bias signal biasing the first avalanche photodiode into a smoothed bias signal; a current detecting unit detecting photocurrent from the second avalanche photodiode, with a multiplying current value corresponding to the multiplying bias level and a non-multiplying current value corresponding to the non-multiplying bias level; a multiplication factor calculating unit calculating a multiplication factor of the second avalanche photodiode based on the multiplying current value and the non-multiplying current value; and a control unit controlling the first level of the bias signal based on the calculated multiplication factor.