Fig. 1. Structure of acoustooptic frequency shifter and schematic of acoustooptic interaction. (a) Typical structure of acoustooptic frequency shifter; (b) schematic of acousto－optic interaction; (c) vector diagram of momentum mismatch

Fig. 2. Three typical assembly dislocation relation diagrams. (a) Lateral dislocation; (b) tilt dislocation; (c) axial dislocation

Fig. 3. Typical axial dislocation diagram. (a) Bilateral dislocation; (b) unilateral dislocation; (c) equivalent unilateral dislocation

Fig. 4. Simulation model and sound pressure level distribution of ultrasonic waves in AOC. (a) Surface sound pressure level of bilateral dislocation; (b) surface sound pressure level of unilateral dislocation; (c) sound pressure level isolines of meridian plane of bilateral dislocation; (d) sound pressure level isolines of meridian plane of unilateral dislocation

Fig. 5. Relationship between ΔL and Δl under mismatch condition and their fitting curve. (a) Bilateral dislocation; (b) unilateral dislocation

Fig. 6. Equivalent propagation path of incident light under different conditions. (a) Bilateral dislocation; (b) unilateral dislocation; (c) position matching

Fig. 7. Transmission interference spectral curves under different conditions. (a) Bilateral dislocation; (b) unilateral dislocation; (c) position matching

Fig. 8. Frequency spectrum and its partial enlargement under different conditions. (a) Bilateral dislocation；(b) unilateral dislocation; (c) position matching

Fig. 9. Optical system using acoustooptic frequency shifter

Fig. 10. Power spectrum signal of system output. (a) Power spectrum without mismatch; (b) power spectrum with mismatch

Fig. 11. Length measurement system without acoustic interaction occurs region

Fig. 12. Transmission spectra of different acousto－optic frequency shifters. (a) SGYF40－1550－1；(b) SGYF80－1550－1; (c) SGYF100－1550－1; (d) SGYF150－1550－1

Fig. 13. Transmission spectrum of glass plate

Table 1. Length of without acoustic interaction occurs region in different acousto－optic frequency shifters