| 摘要 |
PROBLEM TO BE SOLVED: To provide a stable semiconductor laser module whose connection efficiency between a semiconductor laser and a core enlarging fiber is high by specifying the enlargement rate of a core and the change rate of a mode field diameter. SOLUTION: The semiconductor laser module 10 is provided with a semiconductor laser 11, a first lens 12, a second lens 13, a core enlargement fiber 14 and an airtight case 20. In the core enlargement fiber, the enlargement rate of the core is set to be more than 1.3 and the absolute value of the change rate of the mode field diameter to be smaller than 6.0×10<-4>μm<-1> . Thus, the dispersion of connection efficiency in the assembled module becomes small and the module of high connection efficiency can stably be manufactured. The change rate of the mode field diameter in the core enlargement fiber 14 can be controlled by various means on the flow rate adjustment of fuel gas and the control of the size and temperature of flame at the time of heating a single mode fiber by a burner and enlarging the core.
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