Design and Implementation of WDM Based Multi-Hop Local Area Network

A fiber optic local area network (LAN) was implemented based on an important optical networking technology - wavelength division multiplexing (WDM) allowing optic fiber to carry several separate and independent optical channels simultaneously. The data network designed is an IEEE 802.5 [1] ring-architecture with multi-hop protocol where each node on network communicates with the adjacent nodes on optic fiber using Vertical Cavity Light Emitting Laser (VCSEL) and PIN photodiode transceiver operating at 1300nm and 850nm wavelengths. The bidirectionality is achieved by wavelength multiplexing and demultiplexing using dichoric beam splitters and fused couplers positioned in each transceiver circuit. The transceiver driver circuitry is designed for the optical to electrical conversion and vice versa of data signal. The digital data is modulated over the laser diode by direct intensity modulation technique. The paper presents a detailed description of network nodes and medium in the WDM multi-hop ring network.