Efficient highly stable laser diode module for single-mode fiber employing a combination of hemispherical ended GRIN rod lens and virtual fiber
An efficient and practical laser diode module is demonstrated forsingle-mode fiber applications. The module is developed through use of anearlier proposed combination lens method, where a hemispherical ended gradedindex rod lens and virtual fiber are employed. Since lens and virtual fibermisalignment tolerances are large in this coupling method, the YAG laser weldingtechnique is easily applicable. This laser diode module has not only a simplestructure but also high coupling efficiency, excellent reproducibility, andextremely high reliability.