Light amplifier

Abstract

Abstract PURPOSE:To obtain the light amplifier which has small gain variation with ambient temperature, etc., by providing a circuit which superposes a high frequency upon the driving current of an LD for excitation. CONSTITUTION:The high frequency current of a high frequency power source 20 is superposed upon the driving current of the exciting LD 17 for the light amplifier through a bias circuit 21. At this time, the frequency of the power source 20 is set to a frequency which is an integral multiple of the reciprocal of the time of the reciprocation of light between the exciting LD 17 and a means 12 for exciting light and then the exciting LD 17 can be put in multimode oscillation efficiently. Therefore, even if an optical coupler 8 varies in size owing to variation in the ambient temperature, etc., the distance between the return means 12 for the exciting light and exciting LD 17 varies slightly, the transmissivity of the exciting LD 17 to reflected light does not vary, so the quantity of the exciting light incident on an optical fiber 5 does not varies and the gain to signal light 3 becomes stable.

Inventors

• 👤 Junichiro Yamashita
• 👤 純一郎 山下

Bibliographic Details