OPTICALLY ACCESSING LOOP (OPAL) NETWORK USING WAVELENGTH-DIVISION-MULTIPLEXING TECHNOLOGY.

A new Optically Accessing Loop (OPAL) network, using an optical accessor as an interface between the optical data highway and the E/O, and O/E converters is proposed. The accessor can branch and insert the optical signals without blocking the optical highway, and can also duplicate the highway by applying wavelength-division-multiplexing (WDM) technology. The OPAL network is expected to be reliable due to the use of multiple routing and skipping of the fault station. Two types of OPAL networks are proposed; non-repeating and burst relay. For the former, a network with a loop length of 5 km and about five remote stations can be applied to the integrated system with many users distributed in a relatively high density. The burst relay system increases the loop length by repeating part of the optical power without sacrificing the reliability of the non-repeating system. System consideration concerning the optical and electrical designs, their characteristics and a preliminary experiment are described.