Light controlled delay of MW signals in LiNbO/sub 3/:Fe

New optically controlled hypersonic delay lines are proposed for MW signals processing. It is shown that their principle of operation is based on the reflection of hypersonic waves by photoinduced Bragg gratings (PBG) in photorefractive media such as photonic crystals. It has been suggested that one can record with PBG in one domain with broadband reflection of hypersonic waves.