Low-noise laser diode (0.78 μm) for video disk reading

Abstract

Various types of visible laser diode have been reported as light sources for optical disk reading, such as audio and video disks. However, among them single-longitudinal-mode lasers need special means, such as super imposing (radio) high frequency on the bias current for applications in video disk reading, which requires about a 30-dB higher SNR than audio disk reading. Because without such means the noise of single-longitudinal-mode lasers increases drastically when a part of the reflected output is returned to the laser diode, resulting in mode jumping. On the other hand, multilongitudinal-mode laser diodes do not show such significant noise deterioration.