LOW-COST HYBRID WDM MODULE CONSISTING OF SIZE CONVERTER INTEGRATED LASER-DIODE AND A WAVE-GUIDE PHOTODIODE ON A PLC PLATFORM FOR ACCESS NETWORK SYSTEMS

This paper describes the technological issues in achieving a low-cost hybrid WDM module for access network systems. The problems which shoul d be resolved in developing a low-cost module are clarified from the v iewpoint of the module assembly in mass production. A design concept f or a low-cost module suitable for mass production is indicated, which simplifies the alignment between a laser diode and a waveguide, and re duces the number of the components such as lenses and mirrors. The low -cost module is achieved by employing a flip-chip bonding method with passive alignment using a spot-size converter integrated laser diode ( SS-LD) and p-i-n waveguide photodiodes (WGPDs) on a planar lightwave c ircuit (PLC) platform. We confirm that the SS-LD and the WGPD provide high coupling efficiency with a large tolerance for passive alignment. To achieve a high-sensitivity receiver, the module is designed to emp loy an asymmetric PLC Y-splitter that prefers a PD responsivity to an LD output power because of the high-coupling efficiency of the LD, and to employ a bare preamplifier mounting to reduce the parasitic capaci tance into a preamplifier. We also demonstrate the dynamic performance for a 50-Mb/s burst signal, such as a high sensitivity, an instantane ous AGC response, and a small APC deviation of the transceiver.