Abstract
Step-index polymer optical fibre doped with Rhodamine B at 2500 ppm level is fabricated. Using the fibre, we have achieved high-gain and high-efficiency optical amplification with a tunable wavelength range from 610 nm to 640 nm, which is significantly red-shifted toward the centre of the communication window (at 650 nm wavelength) of methyl methacrylate-based polymer optical fibre.