| abstract |
An optical resonator having excellent temperature characteristics, allowing mass-production, having an excellent long-time stability, and forming wavelength control module capable of coping with an increase in density of wavelength interval, wherein two substrates having a specified reflectance are disposed opposedly and parallel to each other through a spacer with the reflection surfaces thereof facing inward, the spacer is formed of a material with a coefficient of linear expansion of almost zero, formed in a block with a specified thickness, and provided with a hollow part passing through in thickness direction, the hollow part communicates with the outside through a groove part, and two substrates are connected to each other on both end faces thereof in thickness direction. |