Characteristics of vad single mode fiber with depressed cladding layer

VAD single mode fiber with depressed cladding layer has been developed. Fabricated fibers have a germanium doped core of index difference ▵+ = 0.2~ 0.3% and a fluorine doped cladding layer of negative index difference ▵- = 0.1~0.4%. The cladding to core diameter ratio is 5 to 9, and the transmission loss is less than 0.5 dB/km at 1.311m. Bending loss increase due to lateral pressure was found to be equal to that of the matched cladding fiber whose index difference ▵ is equal to the total index difference of the depressed cladding fiber (▵ = ▵+ + ▵-). The chromatic dispersion, however, was rather similar to that of the matched cladding fiber which has the same concentration of germanium in the core, or the same positive index difference (▵ = ▵+), yielding the low dispersion at 1.3 μm. The fusion splice loss was also confirmed to be as small as the matched cladding fiber. The low transmission loss was maintained throughout the cabling process.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.