Low-loss tunable integrated acoustooptical wavelength filter in LiNbO/sub 3/ with strong sidelobe suppression

An integrated acoustooptical double-stage wavelength filter in LiNbO/sub 3/ has been developed using acoustooptical polarization converters and polarization splitters as basic components integrated on the same chip. Ti-indiffusion technology is used throughout to fabricate the device. The packaged and pigtailed filter has low insertion losses (4.1 dB fiber-to-fiber), low-polarization dependence (0.1 dB) and a strong sidelobe and baseline suppression (>30 dB). Its tuning range exceeds the gain bandwidth of erbium-doped fiber amplifiers around 1550 nm.