All fibre sliding frequency soliton laser

Recently, impressive progress has been made in the development of fiber acoustooptic frequency shifters using acoustically driven, four-port null couplers. Losses as low as 0.1 dB and frequency conversion efficiencies higher than as 99% with carrier suppression of >30 dB have been obtained for acoustic drive powers as low as 2 mW at frequency shifts as high as 10 MHz. Moreover, the devices also act as tunable optical bandpass filters, can be designed to be polarising, and do not give rise to internal back reflections. As such they are ideal modelocking elements for sliding frequency fibre soliton lasers in which frequency shifting, filtering, and polarising components are required. Fibre frequency shifters perform all of these function simultaneously and permit the construction of extremely simple all-fibre, wavelength tunable, low-loss laser cavities. In all schemes demonstrated to date these functions have been performed by discrete/lossy bulk componentry