Sumitomo Electric Industries Ltd. said Tuesday it will invest 35 billion yen in fiscal 2000 on the construction of manufacturing facilities for optical fibers and other telecommunications devices related to wavelength division multiplexing technology.

The capital outlay is designed to increase output of WDM devices, which allow for large-capacity, high-speed transmissions of signals through fiber-optic networks, it said.

WDM technology involves bundling optical signals of different wavelengths and sending them through a single optical fiber, thus increasing the transmission capacity of a fiber-optic cable.

Up to 160 laser emitters create optical signals, which are then bundled into a single light ray.

Sumitomo Electric said it will invest a major part of the 35 billion yen into the manufacturing of a special semiconductor laser device for amplifying bundled rays.

Part of the outlay will be to manufacture optical link devices for converting digital electrical signals into optical signals.

Other funds will be used to improve the performance of the company's existing optical fibers to transmit bundled signals with higher density over a greater distance, it said.