Abstract 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.
A semiconductor laser comprising: a resonator having two resonator cavities, which have different lengths, all in a unitary structure, one of said resonator cavities having a length 1/m (where m is an integer) that of the other of said two resonator cavities; and a reflection mirror which is common to said two resonator cavities and which has a distributed feedback construction.
Claim 2
Dependent Claim
61 words
A semiconductor laser comprising: a resonator having two resonator cavities, which have different lengths, all in a unitary structure, one of said resonator cavities having a length 1/m (where m is an integer) that of the other of said two resonator cavities; and a reflection mirror which is common to said two resonator cavities and which has a distributed feedback construction.
Claim 3
Dependent Claim
34 words
A semiconductor laser according to claim 1, further comprising a high-frequency modulation region which is disposed within a longer one of said two resonator cavities, for performing high-frequency modulation with a fundamental mode-locking frequency.
Claim 4
Dependent Claim
21 words
A semiconductor laser according to claim 2, further comprising a high frequency generator which is coupled to said high-frequency modulation region.
Claim 5
Dependent Claim
25 words
A semiconductor laser according to claim 1, further comprising a saturable absorption region which is disposed within a longer one of said two resonator cavities.
Claim 6
Dependent Claim
19 words
A semiconductor laser according to claim 4, wherein said saturable absorption region is reverse-biased by a DC power supply.