PURPOSE: To eliminate the necessity of bending a bare optical fiber part, and eliminate the occurrence of rupture by projecting an optical fiber introducing sleeve only to the outside from an optical element housing casing, and joining and sealing the bare optical fiber part in it.
CONSTITUTION: An inner chamber casing 10 is composed of a casing main body 10a and a cover body 10b, and a through-hole 11 is formed in the side wall part 10c. A cylindrical projecting body 12 extends toward only the outside of the side wall part 10c from an outlet part of the through-hole 11. This cylindrical projecting body 12 has a hollow part 13 continuing to the through-hole 11. A tip surface of bare optical fiber 4a is connected to an end surface of an optical element 1, and forms a joining part 8. A clearance between an inside surface of the hollow part 13 of cylindrical projecting body 12 and a peripheral surface of the bare optical fiber 4a inserted in it, is filled with and sealed by a moisture nonpermeable joining material 14, for example, solder. Thereby, when influence of a difference in a thermal expansion quantity between a casing 10 and optical fiber 4 is reduced to an ignorable level, the necessity of bending a bare fiber part in a casing inner chamber 2 can be eliminated.
SHIRAISHI MASARU
SAKUMA MITSURU
TATEYAMA TAKASHI
SAITO TSUTOMU
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