| 摘要 |
PROBLEM TO BE SOLVED: To provide a temperature independent laser which can suppress mode hopping and can produce an oscillation frequency independent of temperature. SOLUTION: In the temperature independent laser, a material 51 having a refractive index temperature coefficient having a sign opposite to the optical waveguide is positioned at an upper-side clad part 14 of a grating waveguide 15 to be formed as a reflection part for formation of a laser cavity in the waveguide. Light guided through a core 13 is leaked even into the clad 14 as part of its energy, senses both of refractive indexes of the core 13 and clad 14, and takes an effective refractive index value intermediate of the both refractive indexes. Accordingly, when the temperature coefficient adjustment material 51 is inserted in a partially or wholly removed part of the upper clad 14 and has a temperature coefficient of a sign opposed to that of the waveguide (in particular, the core 13), the temperature coefficient can be set to zero by adjusting the temperature coefficient of the effective refractive index. As a result, mode hopping can be suppressed to the temperature change and there can be realized a laser which has a constant oscillation frequency. |
