Fabricating Lensed Fiber Using a Novel Polishing Method

In optical communication systems, 980 nm high-power laser modules are applied for long-distance communication amplifiers. Since the mode field of the 980 nm laser diodes is different from single-mode fibers, coupling losses may occur. In order to improve this problem, lensed fibers have been used widely recently, such as lensed fiber employing quadrangular-pyramid-shaped fiber endface (QPSFE). The QPSFE can easily yield any elliptical microlens aspect ratio to match the far field of the high-power laser diode but the fiber endface must be polished and then spliced during present manufacturing process. It is a time-consuming task and the melting depth of the fiber endface is controlled with difficulty. This study develops a novel fiber endface polishing method for manufacturing the lensed fiber employing QPSFE. Using this new method, the coupling efficiency exceeds 70%.