Investigation of cascadability and optimum inter-regenerator spacing in transmission with all-optical 3R regeneration

Transmission with cascaded all-optical 3R regeneration is reported using a reconfigurable fibre loop to investigate, for the first time, the impact of varying the inter-regenerator spacing on long distance transmission. Error-free transmission at 10 Gb/s over 20000 km of standard single-mode fibre was achieved with inter-regenerator spacing range of 150-600 km, corresponding to an OSNR range of 30-23 dB/0.1 nm at the regenerator input