Koichi Maeno, Takahiro Ueno, Masato Shiino, Yutaka Arai, Kazuhiro Takayama, Katsuki Suematsu, Masao Shinoda, Koichi Takagi, Hiroyuki Yamada, Kiyoshi Midorikawa
Injection molding is attracting attention as a short-cycle molding method for Mini-MT ferrules that comprise optical connectors. The authors investigated the material, molds, molding conditions, and polishing technologies for injection molding Mini-MT ferrules, and succeeded in developing the ferrules having the same level of precision as those by conventional transfer molding. The 4-fiber Mini-MT connector comprised of the developed 4-fiber Mini-MT ferrules gave such excellent optical characteristics as 0.107 dB on average for insertion loss and 45 dB or better on average for return loss, in addition to stabilized insertion loss changes at reliability tests. Furthermore, the insertion and return losses of the 2-fiber Mini-MPO connector comprised of the 2-fiber Mini-MT ferrules were 0.18 dB on average and 45 dB or better on average respectively, and the connector showed small insertion loss changes.
Thus, optical characteristics of injection molded Mini-MT ferrules proved to be equivalent to those of transfer molded ferrules. Since it is possible to make the cycle time of injection molding shorter than that of transfer molding thereby enabling low-cost production, the use of injection molded ferrules is expected to broadly spread in future.