HERMETICALLY SEALED OPTICAL DEVICE

PROBLEM TO BE SOLVED: To restrict the oxidation of fluxless Sn(91)-Zn(9) solder in a hermetically sealed package.SOLUTION: A waveguide type wavelength conversion element 1 which requires hermetic seal, a metal holder 2 and a thermo-module 3 are sealed air-tight in a hermetically sealed package 4. A heat radiation face 3b of the thermo-module 3 is joined to an inner region 4b of the hermetically sealed package 4 with fluxless Sn(91)-Zn(9) solder 5. Oxygen-free inert gas 7 is filled in a space inside the hermetically sealed package 4. This results in that the fluxless Sn(91)-Zn(9) solder is not oxidized even in a hermetically sealed state. Also, because the package is sealed air-tight, the waveguide type wavelength conversion element 1, etc. can be protected against dust and moisture, etc.