The selection of the initial shift register of M-sequence is a key technique in pulse compression waveform design whose pulse compression waveform must have low peak power and large compression ratio.

The shift of reflective wavelength of one FBG under external strain is translated into a change in time interval of the optical pulse from another FBG drived by a PZT plate.

In some sense and at not too high orders, it can be better than Kaiser's window which is taken as the unit pulse response of a non-recursive shift variant filter here.