Tunable Lasers Based On Multimode Interference Effects

We reviewthe development of multimode interference (MMI) basedwavelength tunable fiber lasers. The key advantages of MMI devices as tunable filters are its band-pass spectral response and the simplicity in their fabrication. Different approaches are reviewed in an effort to achieve wide tuning ranges. The maximum tuning range is close to 90 nm and a side-mode suppression ratio (SMSR) better than 50 dB is demonstrated with a single MMI filter. The wide tuning range demonstrates the potential of MMI devices for tunable laser applications