Title:
【発明の名称】光帰還式光検出装置
Document Type and Number:
Japanese Patent JP2931226
Kind Code:
B2
Abstract:
An optical feedback photodetection apparatus of the present invention achieves high-speed response while minimizing noise to obtain a high S/N ratio and a wide dynamic range. In the apparatus, on the basis of a modulated drive signal from a drive signal output circuit, a semiconductor laser outputs a light beam modulated at a frequency f0 to irradiate an object to be measured through an optical system, and the light beam reflected by the object is fed back to the semiconductor laser through the optical system. The intensity of the light beam from the semiconductor laser having an optical amplification function varies due to the return light beam. A photoconductive light-receiving device to which a modulated voltage signal at the frequency f0 from a voltage application unit is applied receives the light beam from the semiconductor laser and having an intensity varying due to the return light beam, thereby performing synchronous detection. A modulated current signal flowing through the photoconductive light-receiving device is converted to a voltage signal by a current/voltage conversion unit, and the low-frequency component of the voltage signal is extracted.
Inventors:
KOISHI JU
SHIRAKAWA KOICHI
TAKESHIMA AKIRA
SHIRAKAWA KOICHI
TAKESHIMA AKIRA
Application Number:
JP1101295A
Publication Date:
August 09, 1999
Filing Date:
January 26, 1995
Export Citation:
Assignee:
HAMAMATSU HOTONIKUSU KK
International Classes:
G01C3/06; G01J1/42; G02B21/00; G11B7/00; G01B11/00; G11B7/005; G11B7/125; G11B7/127; G11B7/13; G11B7/135; H01S5/50; H01S5/062; H01S5/068; (IPC1-7): G01J1/42; G11B7/00; G11B7/125; G11B7/135
Domestic Patent References:
| JP5694530A | ||||
| JP4281243A | ||||
| JP392732A |
Attorney, Agent or Firm:
Yoshiki Hasegawa (3 outside)