Abstract: Methods that create an array of BAW resonators by patterning a mass load layer to control the resonant frequency of the resonators and resonators formed thereby, are disclosed. Patterning the surface of a mass load layer and introducing apertures with dimensions smaller than the acoustic wavelength, or dimpling the mass load layer, modifies the acoustic path length of the resonator, thereby changing the resonant frequency of the device. Patterns of variable density allow for further tuning the resonators and for individualized tuning of a resonator in an array of resonators. Patterning a reflowable material for the mass load layer, thereby providing a variable pattern density and distribution followed by elevating the temperature of the mass load layer above its melting point causes the material to liquefy and fill into the apertures to redistribute the mass load layer, thereby, upon subsequent cooling, providing resonators with a predetermined desired resonant frequency.

Abstract: A tunable acoustic resonator device has a piezoelectric medium as a first thin film layer and a tunable crystal medium as a second thin film layer. The tunable crystal medium has a first acoustic behavior over an operating temperature range under a condition of relatively low applied stress and a second acoustic behavior under a condition of relatively high applied stress. The acoustic behaviors are substantially different and, consequently, the different levels of applied stress are used to tune the acoustic resonator device. Compared with the tunable resonator device consisting of only tunable crystal medium, a device having both the piezoelectric and tunable crystal medium has advantages such as larger inherent bandwidth and less nonlinearity with AC signals. The device also requires a smaller applied stress (i.e. bias voltage) to achieve the required frequency tuning.

Abstract: A tunable acoustic resonator device has a piezoelectric medium as a first thin film layer and a tunable crystal medium as a second thin film layer. The tunable crystal medium has a first acoustic behavior over an operating temperature range under a condition of relatively low applied stress and a second acoustic behavior under a condition of relatively high applied stress. The acoustic behaviors are substantially different and, consequently, the different levels of applied stress are used to tune the acoustic resonator device. Compared with the tunable resonator device consisting of only tunable crystal medium, a device having both the piezoelectric and tunable crystal medium has advantages such as larger inherent bandwidth and less nonlinearity with AC signals. The device also requires a smaller applied stress (i.e. bias voltage) to achieve the required frequency tuning.

Abstract: A tunable acoustic resonator device has a piezoelectric medium as a first thin film layer and a tunable crystal medium as a second thin film layer. The tunable crystal medium has a first acoustic behavior over an operating temperature range under a condition of relatively low applied stress and a second acoustic behavior under a condition of relatively high applied stress. The acoustic behaviors are substantially different and, consequently, the different levels of applied stress are used to tune the acoustic resonator device. Compared with the tunable resonator device consisting of only tunable crystal medium, a device having both the piezoelectric and tunable crystal medium has advantages such as larger inherent bandwidth and less nonlinearity with AC signals. The device also requires a smaller applied stress (i.e. bias voltage) to achieve the required frequency tuning.

Abstract: Methods that create an array of BAW resonators by patterning a mass load layer to control the resonant frequency of the resonators and resonators formed thereby, are disclosed. Patterning the surface of a mass load layer and introducing apertures with dimensions smaller than the acoustic wavelength, or dimpling the mass load layer, modifies the acoustic path length of the resonator, thereby changing the resonant frequency of the device. Patterns of variable density allow for further tuning the resonators and for individualized tuning of a resonator in an array of resonators. Patterning a reflowable material for the mass load layer, thereby providing a variable pattern density and distribution followed by elevating the temperature of the mass load layer above its melting point causes the material to liquefy and fill into the apertures to redistribute the mass load layer, thereby, upon subsequent cooling, providing resonators with a predetermined desired resonant frequency.

Abstract: Methods that create an array of BAW resonators by patterning a mass load layer to control the resonant frequency of the resonators and resonators formed thereby, are disclosed. Patterning the surface of a mass load layer and introducing apertures with dimensions smaller than the acoustic wavelength, or dimpling the mass load layer, modifies the acoustic path length of the resonator, thereby changing the resonant frequency of the device. Patterns of variable density allow for further tuning the resonators and for individualized tuning of a resonator in an array of resonators. Patterning a reflowable material for the mass load layer, thereby providing a variable pattern density and distribution followed by elevating the temperature of the mass load layer above its melting point causes the material to liquefy and fill into the apertures to redistribute the mass load layer, thereby, upon subsequent cooling, providing resonators with a predetermined desired resonant frequency.

Abstract: A tunable acoustic resonator device. The device has a piezoelectric medium as a first thin film layer and a tunable crystal medium as a second thin film layer. The tunable crystal medium has a first acoustic behavior over an operating temperature range under a condition of relatively low applied stress and a second acoustic behavior under a condition of relatively high applied stress. The acoustic behaviors are substantially different. The tunable crystal medium has a highly field-polarizable and lattice-deformable, substantially centrosymmetric structure over an operating temperature range under a condition of relatively low applied stress. The tunable crystal medium has a substantially non-centrosymmetric structure over said operating temperature range under a condition of relatively high applied stress. The dielectric permittivity of the tunable crystal medium is at least 100 at the relatively low applied stress.

Abstract: Silica sol techniques are described for making thick silica or silica based films useful for planar optical waveguides. The process involves coating of a colloidal silica sol onto a substrate, drying the sol, and consolidating the dried sol to form the planar waveguide. Coating is performed in a simple operation, either by dipping, or preferably by spin coating. In a preferred embodiment the substrate is coated with a wetting agent prior to spin coating. It is found that the wetting agent substantially improves the thickness uniformity of the layer. Thick waveguide layers may be produced by repeating the coating process one or more times to produce a layer with the desired thickness. Buried waveguides are produced by forming a doped core layer, patterning the doped core layer and using the coating technique of the invention to form the cladding material.

Abstract: Silica sol techniques are described for making thick silica or silica based films useful for planar optical waveguides. The process involves coating of a colloidal silica sol onto a substrate, drying the sol, and consolidating the dried sol to form the planar waveguide. Coating is performed in a simple operation, either by dipping, or preferably by spin coating. In a preferred embodiment the substrate is coated with a wetting agent prior to spin coating. It is found that the wetting agent substantially improves the thickness uniformity of the layer.