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. 13, 1998
Filed:
Apr. 15, 1996
Hiroyuki Itou, Sapporo, JP;
Michikazu Shima, Kawasaki, JP;
Yoshihito Onoda, Kawasaki, JP;
Yuji Tamura, Sapporo, JP;
Fujitsu Limited, Kanagawa, JP;
Abstract
A control apparatus for an optical amplifier such as an erbium-doped optical-fiber (EDF) amplifier suppresses overshooting of ALC control at power on and at the time of input light restoration from an off condition, while ensuring quick starting. At power on and at the time of input light restoration from an off condition, an idling current (IDC) reference value generating circuit generates an IDC reference voltage that increases to a value sufficiently greater than a value in a normal operating condition with a time constant corresponding to a rise time of the EDF, and thereby controls a laser diode for pumping the EDF. The voltage may be set to a value larger than the value in the normal operating condition for a predetermined period of time by using a timer.