<title>Low-cost bidirectional optical transmitter/receiver module for subscriber system</title>

Abstract

A low cost optical transmitter/receiver module is essential for optical subscriber systems. Hybrid integration of optical components and alignment free assembly are effective techniques for such low cost module. We newly developed a bi-directional optical transmitter/receiver module using passive alignment techniques for a laser diode (LD) mounting on a Planar Lightwave Circuit (PLC). Compact module size of 26mm X 10mm X 3mm is achieved. A spot-size converted laser diode is passively mounted on a PLC chip by detecting each alignment marks on the LD and the PLC chip. Low optical coupling loss of less than 4.5 dB is attained. The PLC chip has the function of Y branch. Alignment marks for LD mounting and a V-groove for fiber alignment are also fabricated on the PLC chip. A fiber is self-aligned on the V-groove. The PLC chip and the other components such as a sub assembled dual photo diode and a receiver-amplifier are also built in a ceramic package. The output power of the transmitter/receiver module is +2dBm at the LD drive current at 45mA. Responsivity of over 0.35A/W is realized. Minimum optical received power of -38dBm at the 50Mb/s burst signal was obtained.