Sonic wave coupler and amplifier with determinable delay characteristics

Claim 2

An amplifier comprising: a substrate element; means for generating elastic energy in said substrate, said energy to propagate at a first predetermined velocity and a predetermined direction; a piezoelectric semiconductive element adjacent said substrate and interfaced therewith, the interface being substantially parallel to said predetermined direction, said piezoelectric element having a second predetermined velocity of propagation for elastic energy less than said first velocity, whereby elastic energy propagating through said substrate in said predetermined direction induces propagation of elastic energy in said piezoelectric element in a direction generally parallel to said interface, said induced elastic energy to generate a travelling electric field within said piezoelectric element; means for applying a fixed electric field across a portion of said piezoelectric element to act in a direction generally parallel to said interface thereby to augment the effects of said travelling electric field to amplify said induced elastic energy; and means for extracting energy from one of said elements.

Claim 3

The amplifier as recited in claim 1, wherein said interface comprises an optically efficient interface formed between said substrate and said piezoelectric element.

Claim 4

The amplifier as recited in claim 1, wherein each of said elements comprises an optically polished planar surface, said surfaces being juxtaposed substantially parallel to each other across a separation of predetermined width between said elements.

Claim 5

The amplifier as recited in claim 3, wherein said interface comprises at least a first fluid layer disposed within said separation to form an interface with each of said planar surfaces, respectively, and having a third velocity of propagation for elastic energy, said third velocity having a value falling within a permissible range of which said first velocity is a maximum.

Claim 6

The amplifier as recited in claim 4, wherein said substrate comprises a member of piezoelectric material, and said means for generating elastic energy in said substrate comprises a first interdigital transducer connected at one end of the planar surface of said substrate, said transducer being connected to a source of electrical pulses for exciting elastic surface waves in said substrate.

Claim 7

The amplifier as recited in claim 5, wherein said substrate comprises a member of X-cut piezoelectric material whereby surface waves excited in said substrate propagate in said predetermined direction.

Claim 8

The amplifier as recited in claim 6, wherein the ratio of said third velocity to said second velocity is such that energy transferring between said elements has major component vectors oriented substantially in said predetermined direction.

Claim 9

The amplifier as recited in claim 7, wherein said piezoelectric element has an optical axis substantially perpen-dicular to the planar surface of said substrate.

Claim 10

The amplifier as recited in claim 8, wherein said means for applying an electric field across said piezoelectric element comprises means for causing current carriers in said piezoelectric element to flow substantially in said predetermined direction.

Claim 11

The amplifier as recited in claim 9, wherein said current carriers flow at a velocity slightly greater than said second velocity.

Claim 12

The amplifier as recited in claim 10, wherein said means for applying an electric field across said piezoelectric element comprises a DC voltage source.

Claim 13

The amplifier as recited in claim 11, wherein said transferring means comprises, in addition, a second fluid layer disposed within said separation, and laterally displaced from said first fluid layer, to form an interface with each of said planar surfaces, respectively.

Claim 14

An acoustic delay-line amplifier comprising: an X-cut piezoelectric substrate having an optically polished planar surface; means for generating Rayleigh waves in said surface, said waves to propagate at a predetermined velocity; a piezoelectric semiconductive element adjacent said substrate and comprising, an optical axis substantially perpendicular to the planar surface of said substrate, an optically polished planar surface spaced from the planar surface of said substrate by a predetermined distance and disposed substantially parallel thereto, said element having a predetermined velocity of propagation for transverse acoustic waves, which velocity is less than said Rayleigh wave velocity; at least a first substantially non-volatile fluid layer disposed within said separation to form an interface with each of said planar surfaces respectively, said layer having a predetermined velocity of propagation for longitudinal acoustic waves which is greater than said transverse wave velocity and has a maximum value substantially equal to said Rayleigh wave velocity, whereby Rayleigh waves propagating along the planar surface of said substrate excite propagation of transverse waves in said element in a direction generally parallel to said separation, said transverse waves to generate a travelling electric field within said element; means for applying a fixed electric field across a portion of said element to act in a direction generally parallel to the direction of propagation of said transverse waves, thereby to augment the effects of said travelling electric field to amplify said transverse waves; and means for extracting Rayleigh waves from said substrate.

Claim 15

An acoustic delay-line amplifier comprising: an X-cut piezoelectric substrate having an optically polished planar surface; means for generating Rayleigh waves in said surface, said waves to propagate at a predetermined velocity; a piezoelectric semiconductive element adjacent said substrate and comprising, an optical axis substantially perpendicular to the planar surface of said substrate, an optically polished planar surface spaced from the planar surface of said substrate by a predetermined distance and disposed substantially parallel thereto, said element having a predetermined velocity of propagation for transverse acoustic waves, which velocity is less than said Rayleigh wave velocity; at least a first substantially non-volatile fluid layer disposed within said separation to form an interface with each of said planar surfaces respectively, said layer having a predetermined velocity of propagation for longitudinal acoustic waves which is greater than said transverse wave velocity and has a maximum value substantially equal to said Rayleigh wave velocity, whereby Rayleigh waves propagating along the planar surface of said substrate excite propagation of transverse waves in said element in a direction generally parallel to said separation, said transverse waves to generate a travelling electric field within said element; means for applying a fixed electric field across a portion of said element to act in a direction generally parallel to the direction of propagation of said transverse waves, thereby to augment the effects of said travelling electric field to amplify said transverse waves; and means for extracting Rayleigh waves from said substrate.