Acoustooptic multichannel spectrum analyzer

The two important parameters which characterize the function of the acoustooptic spectrum analyzer are diffraction efficiency and frequency bandwidth. However, diffraction efficiency and bandwidth cannot be increased at the same time for the conventional acoustooptic spectrum analyzer. In this case, the large transducer bandwidth cannot be used because of the smaller intrinsic bandwidth as the interaction length is increased. The concept of eliminating the trade-off between diffraction efficiency and bandwidth is based on the channelization of the device to cover the whole transducer bandwidth. The property of each channel is determined by the intrinsic bandwidth, which becomes smaller as the diffraction efficiency is increased. Therefore, we can increase the diffraction efficiency independent of the bandwidth if we increase the number of channels accordingly. The channelization can be achieved by either applying the acousto-electrooptic effect or using polychromatic lightwaves.