A triplexer module using cascade directional coupler for fiber-to-the-home

초록

We present the design and fabrication of a newly conceived triplexer optical microsystem that can provide bases for gigabit passive optical network (GPON) applicable for fiber-to-the-home (FTTH) network. The FTTH microsystem based on GPON can offer high information capacity services like triple play service (TPS). We designed the triplexer in the form of a planar optical integrated circuit using cascaded directional couplers to provide three different wavelengths: one for the upstream and the other two for downstream, very much like a TPS. The upstream uses 1310 ? for voice and data from the optical network terminal (ONT) to the optical line terminal (OLT) on the central office (CO). The downstream uses 1490 ? for voice and data and the other downstream uses 1550 ? for video from OLT to ONU. The triplexer proposed here is designed to reduce the fabrication process in comparison with other triplexer designs. We analyzed its performance characteristics by BPM method. The optical crosstalk of the 1310 ? signal to the 1490 ? signal and the 1550 ? signal are -56.1dB and -46.4dB, respectively in the upstream. The optical crosstalk in the downstream is -50dB. The optical crosstalk reaching less than -30dB in the downstream is 15nm. This wide bandwidth allows sufficient tolerance to the fabrication error and to the temperature changes. We will also present an experimental prototype and some experimental results.