摘要 |
A semiconductor laser is provided which is capable of generating a train of ultrashort light pulses with an ultrahigh repetition frequency and which is useful in optical communications and optical information processing. The semiconductor laser is a mode-locked semiconductor laser which has two resonator cavities which are formed by two facets and a distributed feedback structure between these two facets. The length of the resonator cavity formed between one facet and the distributed feedback structure is 1/m (where m is an integer) of the length of the resonator cavity formed by the other facet and the distributed feedback structure. A saturable absorption region and a high-frequency modulation region are provided within the longer of the resonator cavities. By making the high-frequency modulation frequency be equal to the round trip frequency of the light within the longer resonator cavity, mode-locked operation is achieved. Because of the linking of the shorter resonator cavity, a train of light pulses having a repetition frequency of m times the mode-locked pulse train frequency is obtained.
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