Transmission characteristics of 116.3 km and 65.1 km graded-index v.a.d. fibres at 1.55 ¿m and 1.3 ¿m

Seven long pieces of fibre with low loss and wide bandwidth properties made by the v.a.d. method were spliced with V-grooves into an 116.3 km graded-index fibre, and three long pieces of fibre into a 65.1 km fibre. Transmission characteristics of these graded-index fibres were measured with a swept-frequency method using InGaAsP/InP b.h. laser diodes operating at 1.55 ¿m (made by low temperature liquid-phase epitaxial growth) and 1.3 ¿m, respectively. The overall transmission losses and 6 dB down electrical bandwidths at the two wavelengths were 37 dB and 16.5 MHz, 35.2 dB and 36.5 MHz, respectively.