A laser noise elimination circuit raises the gain of a first TIA and at the same time reflected light from an optical disc of a laser beam is subjected to photoelectric conversion by means of a photo detector and a second TIA to obtain an RF signal. Then, the direct current component of the FPD signal obtained by photoelectric conversion of part of the laser beam by means of another photo detector and the first TIA is cut out by a high pass filter and then subtracted by a subtracter. The gain of the first TIA is raised in a read mode of operation for reading data from the optical disc and lowered in a write mode of operation for writing data onto the optical disc so as to always effectively eliminate only the laser noise from the RF signal and prevent the circuit from being saturated in a write mode.

 
Web www.patentalert.com

< Hybrid high power laser to achieve high repetition rate and high pulse energy

> Surface-emission laser diode operable in the wavelength band of 1.1-1.7 micrometers and optical telecommunication system using such a laser diode

> Method and system for integrated inertial stabilization mechanism

~ 00544