| 摘要 |
PROBLEM TO BE SOLVED: To provide a distribution feedback type semiconductor laser, which can prevent single-mode characteristics from deteriorating excessively, even when the waveguide is different in equivalent refractive index and also prevent a mode hopping (caused by changes in Bragg oscillation conditions under the influence of hole burning even at high-output time. SOLUTION: A laser element has a low-κregion 9, where a coupling coefficientκis made small on a laser element front side where signal light for transmission is transmitted and a high-κregion 10, where the coupling coefficientκis made large on a laser element rear side (position L in laser element), where monitor signal light is obtained and the coupling coefficientκvarious continuously from the front to the rear of the element; and the distribution feedback type semiconductor laser having higher single-mode characteristics and higher output characteristic than a conventional example which varies in coupling coefficient abruptly fromκ1 toκ2 at a phase shift position can be manufactured with a high yield and stable single-mode oscillation is actualized, even at high- output time and high-speed modulation time.
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