PURPOSE: To suppress the shifting of a light emitting point by the temperature change caused by the difference of the thermal expansion coefficient between a metallic block for heat radiation and a package stem, and lessen the fluctuation of optical output, and also, lessen the tracking error of a semiconductor laser module.
CONSTITUTION: A metallic block 102 for heat radiation is made extensively in the direction of a semiconductor laser device 103 being placed, whereby this emitter is made in such structure that the light emitting point 104 of a semiconductor laser device 103 is positioned on the center G of gravity of the metallic block 102 for heat radiation or in its vicinity and that the light emitting point 104 is positioned on the center axis A of a package stem 101. Moreover, a stem 1 is attached so that the surface may incline by a certain angle from the face vertical to light emission, and the assembling is performed in geometric arrangement such as that the length of the line expansion by the stem at the surface vertical to light emission and the length of the line expansion by the block may negate each other.
OMURA ETSUJI
TAKEMOTO AKIRA
SHIGIHARA KIMIO
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