Low-loss submarine optical fibre cable for repeaterless submarine transmission system employing remotely pumped EDF and distributed Raman amplification

A low-loss submarine optical fibre cable for a long-distance repeaterless submarine transmission system employing remote pumping is described. The features of this system are an increased signal power budget and the provision of cost-effective submarine transmission systems that are easy to maintain. The relationship between the signal and pump losses of optical fibre needed to achieve a repeaterless submarine transmission system operating at 2.5 Gbit/s over a distance exceeding 370 km were investigated. A submarine optical fibre cable based on the results was manufactured and confirmed to have low-loss and stable transmission characteristics for practical applications in submarine repeaterless transmission systems.