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:
Mar. 28, 2000
Filed:
Jun. 03, 1997
Tadashi Koga, Tokyo, JP;
Takaaki Ogata, Tokyo, JP;
Hitoshi Oguri, Chiba, JP;
Takashi Nakamura, Chiba, JP;
NEC Corporation, Tokyo, JP;
Sumitomo Osaka Cement Co., Ltd., Tokyo, JP;
Abstract
An optical receiver board wherein, a signal light is amplified in an optical fiber amplifier. The amplified signal light is supplied to an electrically driven optical wavelength-tuning filter such as a multi-layered film interference filter, through which a signal light of a predetermined wavelength bandwidth is transmitted. The transmitted signal light is divided into first and second signal lights. The first signal light is converted to an electric signal which is amplified by an equalizing amplifier, and an amplified electric signal is supplied to a discrimination circuit, in which an information electric signal is generated by using a timing signal. The optical wavelength-tuning filter comprises a rotation actuator having a magnet-rotating portion and control coils, and an optical filter member fixed to the top of the magnet-rotating portion. In operation, the wavelength-tuning filter is swept by a sweep signal, so that an electric signal converted from a signal light transmitted through the optical wavelength-tuning filter becomes a predetermined value, and the tracking control is carried out to maximize power of the transmitted signal light. The inclination angle of the optical filter member is changed by controlling currents flowing through the control coils of the actuator, so that a transmission center wavelength of the signal light is adjusted.