Semiconductor laser
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsToshitaka Aoyagi, Satoshi Shirai
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Abstract
In a refractive index coupling distributed semiconductor laser having a Λ/2-phase-shift distributed feedback structure having a diffraction grating having a refractive index coupling property on an active layer, when viewed in a light distributed feedback direction, a value of (duty of a high refractive index portion)/(duty of a low refractive index portion) of a diffraction grating in a rear end face region is set to be larger than that of a diffraction grating in a front end face region. In this manner, a coupling coefficient κ2 in a front end face region of a conventional semiconductor laser is set to be smaller than a coupling coefficient κ1 in a rear end face region and is set to be larger than 100 cm−1.
Claims9
A refractive index coupling distributed feedback semiconductor laser comprising a phase-shift structure, wherein when viewed from an almost central portion in a light distributed feedback direction in a region in which diffraction gratings are formed, an average coupling coefficient κ2 of a diffraction grating on one end face side is smaller than an average coupling coefficient κ1 of a diffraction grating on other end face side, and the coupling coefficient κ2 exceeds 100 cm−1.
A complex coupling distributed feedback semiconductor laser of a complex coupling type in which an absolute value of a real part of a coupling coefficient is four or more times an absolute value of an imaginary part of the coupling coefficient, comprising a phase-shift structure, wherein when viewed from an almost central portion in a light distributed feedback direction in a region in which diffraction gratings are formed, an average coupling coefficient κ2 of a diffraction grating on one end face side is smaller than an average coupling coefficient κ1 of a diffraction grating on other end face side, and the coupling coefficient κ2 exceeds 100 cm−1.
Dependencies are inferred from the claim text.