SEMICONDUCTOR SHORT PULSE LIGHT SOURCE AND GENERATING METHOD OF SHORT LIGHT PULSE TRAIN

摘要

PURPOSE:To generate a short light pulse train which has a frequency positive- integer-times as high as the frequency of a modulation signal by a method wherein one or more gain modulation regions or absorption modulation regions are periodically provided with specific position relations in an optical resonator. CONSTITUTION:A laser which is used for ultra-high optical communication has gain modulation regions 9 which change an optical gain in regard to a time and passive waveguides 25 and 26 in its optical resonator. One or a plurality of the gain modulation regions 9 are provided along a route through which a light travels in the optical resonator in such a manner that an optical length which the light travels since it starts from the gain modulation region till it reaches the adjacent or the same gain modulation region is one positive-integer' th as short as an optical length which the light travels to make a round trip in the optical resonator. With this constitution, the light is made to pass through a plurality of the gain modulation regions 9 while it makes a round trip in the optical resonator and a light pulse train having a higher frequency than an external modulation frequency can be generated.