Technology Investigation On The Coupling Between LD And Tapered Fiber

The paper put forward a novel method for mode and power coupling between the laser diode and the fiber. A new structure as tapered and semi-tapered fiber is used in this method, which has the advantage of easily manufacturing, simply packing, low cost and high coupling efficiency and is based on the characters of the laser diode and the fiber mode field. The tapered structure can be made by skiving, eroding and drawing.According to the coupling theory, tapered fiber is optimized to increase the coupling efficiency and quality between the laser diode and the fiber by taking account in the ellipse field of the laser diode outputting. For the coupling between the laser diode and the tapered single-mode fiber, the overlap integral is used to compute the coupling efficiency on the basis that the laser diode outputting mode field and the fiber eigenmode field is approximated to basic-mode Gauss field. And based on the same approximation, the coupling efficiency between the semi-tapered fiber and the laser diode is calculated by using the Ray-Traced Method. The parameters are analyzed for the effect on the coupling efficiency and give the theory foundation to optimize the design of the tapered fiber coupling system.The coupling efficiency can obtain 75-85% at the wide working distance of 100-200um.The tapered and semi-tapered fiber can be arranged in line or array, which has the wide application to the Laser Diode Pumping Solid State Laser and the power outputting of the high-power laser diode array.