A four-wavelength all-fibre laser for wavelength division multiplexing system

A novel four-wavelength all-fibre laser based on fibre Bragg gratings is pr esented. The four wavelengths are 1555.8, 1556.6, 1557.4 and 1558.2 nm, res pectively. Each output laser is <0.3 nm in line-width and >1 mW in power. T he suppression ratio between adjacent wavelengths is > 30 dB. The laser was applied in a wavelength division multiplexing (WDM) system and the 100 km transmission of 1.2 Gb/s nonreturn-to-zero code, 1.2 Gb/s return-to-zero co de, 2.5 GHz analogue signal and 5 GHz analogue signal was realised with it.