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:
Feb. 27, 2001
Filed:
Jan. 18, 2000
Makoto Haneda, Takasaki, JP;
Hiroaki Hanawa, Hino, JP;
Other;
Abstract
An optical transmission device obtains driving control data corresponding to a temperature detected by a temperature detection circuit (,) from memory means (,), controls a driving current to be supplied to a laser diode (,) based on the driving control data, and measures a driving current to be actually supplied to the laser diode whose emission power is held constant by an automatic optical output control circuit (,). Further, when the difference between the measured driving current and a driving current determined by the driving control data corresponding to the detected temperature at that time exceeds an allowable range, the optical transmission device updates the driving control data. Upon determination of the deterioration of the laser diode, the progress of the deterioration of the laser diode is determined based on the difference between a driving current defined by driving control data corresponding to a newly measured temperature and an actual driving current formed by automatic optical output control. Therefore, a distinction between whether an increase in driving current due to the automatic optical output control results from the deterioration of the laser diode and whether it results from a variation in ambient temperature is reliably made.