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. 21, 1995
Filed:
Mar. 30, 1994
NEC Corporation, Tokyo, JP;
Abstract
A frequency stabilization method of a semiconductor laser is provided. A driving current, a forward voltage and an output light power of the laser mounted on a heat sink is detected. A temperature of the heat sink is also detected. A consumption power of the laser is obtained from the driving current and voltage thus detected, providing a relationship between the output light power and the consumption power. The driving current is controlled so that the output light power is kept constant, and the temperature of the heat sink is controlled based on the relationship so that a temperature of an active layer of the laser is maintained. The output light power is kept constant and at the same time, any temperature change of the active layer is cancelled through the temperature control of the heat sink. Even if the consumption power changes due to an leakage current and/or a recombination current without luminescence to maintain the output light power during long time operation, the temperature of the active layer is maintained by cancelling the consumption power change through the temperature control of the heat sink. Thus, the oscillation frequency of the semiconductor laser can be stabilized at a given value.