| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical information reproducing device with a low noise due to return light even when an optical path length is short in the optical information reproducing device having a self-excited oscillating semiconductor laser element as a light source. SOLUTION: In this optical information reproducing device, when a period of an oscillation pulse wave under the condition that the used semiconductor laser element hasn't return light is defined T, and a pulse width that the peak intensity of the pulse wave is provided by 10% or above is TP, the T and TP are provided by the relations: TP<4L/C, T>TP+2L/C. By making it the optical information reproducing device satisfying the above-mentioned conditions, the low noise is obtained even when the optical path length is short. Then, further, by providing the relation between the pulse period T and the pulse width TP by the relation: TP/T<1/2, the lower noise is obtained. |
