CABLING OF SINGLE-MODE FIBERS.

As a consequence of recent advances, single-mode (SM) fibers will probably be used earlier than expected as the transmission medium in large-capacity optical communication systems. With minimum fiber losses of 0. 5 dB/km (at 1. 3 mu m), fusion-splice losses of 0. 2 dB, and connector losses of 0. 5 dB having been achieved, repeater spacings of 50 km appear to be feasible. Uncertainty still exists, however, whether such ultra-low losses can be maintained in cabled fibers while preserving their original transmission characteristics. It is found that single-mode fibers can be cabled without incurring excess losses in a broad wavelength region of the single-mode domain.