Study on the narrow bandwidth integrated acousto-optic tunable filter

With the theory of coupling mode the conversion of acousto-optic modes in LiNbO₃ acousto-optic waveguide is analyzed. The performance parameter of the integrated acousto-optic tunable filter, such as filter bandwidth, wavelength tunable range and drive power, are discussed. The designed IAOTF samples are fabricated by Ti: diffused technology on x-cut y-propagation LiNbO₃ substrates. The measurement system is setup. The high performances of the IAOTF samples, such as the filter bandwidth (FWHM) of 0.85 nm, wavelength tunable range of 100 nm, drive power of 40 mW at the center wavelength 1554 nm, are achieved. In additional, the problems of the sidelobe and super narrow bandwidth IAOTF are presented, which influenced the IAOTF performance especially in OADM system.