Surface wave resonator cascade

Claim 2

A grating resonator cascade comprised of a medium on which surface waves will propagate, and grating means disposed on said medium for forming first and second grating resonators for said surface waves, said resonators having respective longitudinal axes lying in different wave propagation tracks of said medium, characterized by means including means external to the cavities of said resonators for coupling a predetermined fraction of resonant wave energy in each resonator out of that resonator along its said axis and into the other resonator along its said axis.

Claim 3

The invention of claim 1 wherein said grating means is comprised of first and second pairs of reflective gratings each forming the cavity of an associated one of said resonators, said resonators being resonant within substantially the same resonant band and at least one grating of each of said pairs being partially transmissive within said band, said coupling means including said one grating of each of said pairs.

Claim 4

The invention of claim 2 wherein said medium is comprised of a material on which surface acoustic waves will propagate, said cascade being further comprised of means responsive to an electrical input signal for introducing surface acoustic wave energy into a selected one of said resonators.

Claim 5

The invention of claim 2 wherein said medium is comprised of a material on which surface optical waves will propagate.

Claim 6

The invention of claims 2, 3 or 4 wherein said external means is comprised of first and second means disposed on said medium, said first means being adapted to reflect at least a portion of the resonant wave energy coupled out of said first resonator to said second means and said second means being adapted to reflect at least a portion of the energy reflected thereto from said first means into said second resonator.

Claim 7

The invention of claim 5 wherein each of said gratings and each of said first and second means is substantially invisible to surface wave energy which is outside a predetermined grating stopband, said grating stopband encompassing said resonant band.

Claim 8

The invention of claim 6 wherein said medium is comprised of a crystalline material for which the phase velocity of said surface waves is substantially temperature invariant in at least one direction with respect to the crystal axes of said material, and wherein said first means is disposed on said medium such that the energy reflected thereby to said second means propagates in said direction.

Claim 9

The invention of claim 7 wherein each of said first and second means is comprised of at least a first respective region of said medium in which a plurality of substantially parallel grooves is formed.

Claim 10

The invention of claims 2, 3 or 4 wherein said external means is comprised of first, second and third means disposed on said medium, said first means being adapted to reflect at least a portion of the resonant wave energy coupled out of said first resonator to said third means, said third means being adapted to reflect at least a portion of the energy reflected thereto from said first means to said second means, and said second means being adapted to reflect at least a portion of the energy reflected thereto from said third means into said second resonator.

Claim 11

The invention of claim 9 wherein said third means is disposed on said medium such that energy incident on said third means is reflected off said third means at an angle equal to the angle of incidence.

Claim 12

The invention of claim 10 wherein each of said first, second and third means is comprised of a respective region of said medium in which a plurality of substantially parallel grooves is formed.

Claim 13

A surface wave device comprising a substrate on which energy in the form of surface waves will propagate, first and second pairs of reflective gratings disposed on said substrate, said gratings defining first and second resonating cavities in respective first and second wave propagation tracks on said substrate, said cavities being resonant in a predetermined frequency band and at least one grating of each of said pairs being partially transmissive to frequencies within said band, characterized by track changer means external to said cavities for directing wave energy within said band which propagates through said one grating of each of said pairs into said one grating of the other of said pairs.

Claim 14

A surface wave device comprising a substrate on which energy in the form of surface waves will propagate, first and second pairs of reflective gratings disposed on said substrate, said gratings defining first and second resonating cavities in respective first and second wave propagation tracks on said substrate, said cavities being resonant in a predetermined frequency band and at least one grating of each of said pairs being partially transmissive to frequencies within said band, characterized by track changer means external to said cavities for directing wave energy within said band which propagates through said one grating of each of said pairs into said one grating of the other of said pairs.

Claim 15

The invention of claim 12 wherein said track changer means includes first and second reflective arrays disposed in said first and second tracks, respectively, said first array being adapted to reflect energy in said first track to said second array, and said second array being adapted to reflect energy received from said first array into said second track.

Claim 16

The invention of claim 13 wherein each of said gratings and each of said arrays is substantially invisible to surface wave energy outside a predetermined grating stopband, said grating stopband encompassing said resonant band.

Claim 17

The invention of claims 12, 13 or 14 wherein said substrate is comprised of a material on which surface acoustic waves will propagate, said device further comprising means disposed in said first cavity for launching surface acoustic wave energy therein in response to an electrical input signal and means disposed in said second cavity for generating an electrical output signal in response to surface acoustic wave energy therein.

Claim 18

The invention of claim 15 further comprising surface acoustic wave electromechanical coupler means disposed on said substrate for coupling a selected portion of the energy within said band in each of said cavities into the other of said cavities.

Claim 19

A U-path filter comprised of: a medium on which surface waves will propagate; and reflecting means disposed on said medium for reflecting at least a portion of said surface waves; characterized in that said reflecting means comprises first, second and third reflecting means for reflecting said surface waves disposed such that a portion of said surface waves incident in a first direction upon said first means is reflected onto said second reflecting means and a portion of said reflected surface waves is further reflected onto said third reflecting means and a portion of said further reflected surface waves are once again reflected by said third reflecting means so as to travel in substantially the opposite direction from said first direction.

Claim 20

A U-path filter comprised of: a medium on which surface waves will propagate; and reflecting means disposed on said medium for reflecting at least a portion of said surface waves; characterized in that said reflecting means comprises first, second and third reflecting means for reflecting said surface waves disposed such that a portion of said surface waves incident in a first direction upon said first means is reflected onto said second reflecting means and a portion of said reflected surface waves is further reflected onto said third reflecting means and a portion of said further reflected surface waves are once again reflected by said third reflecting means so as to travel in substantially the opposite direction from said first direction.

Claim 21

The U-path filter as defined in claim 17 wherein said first reflecting means is disposed such that the reflected portion of surface waves incident thereon along said first direction for which the surface wave phase velocity does not vary substantially with temperature travels along a second direction for which the surface wave phase velocity does not vary substantially with temperature; said second means is disposed such that a normal to the effective reflecting surface of said second means is parallel to said first direction and a direction about which the surface wave velocity varies symmetrically, whereby the reflected portion of the surface waves incident thereon along said second direction travels along a third direction for which the surface wave phase velocity does not vary substantially with temperature; and said third means is disposed such that the reflected portion of surface waves incident thereon along said third direction travels opposite said first direction.

Claim 22

The U-path filter as defined in claim 17 wherein said medium is comprised of a material on which surface optical waves will propagate.

Claim 23

The U-path filter as defined in claim 17 wherein said medium is comprised of a material on which surface acoustic waves will propagate.

Claim 24

The U-path filter as defined in claim 17 wherein at least one of said reflecting means are weighted.

Claim 25

The U-path filter as defined in claim 21 wherein said first reflecting means and said second reflecting means are weighted.