Acousto-optic modulators enhanced by sub-wavelength acoustic waveguide

An acousto-optic modulator enhanced by a sub-wavelength acoustic waveguide, comprising:

• a substrate, wherein the substrate includes a sapphire underlayment and a silicon dioxide layer disposed on the sapphire underlayment;
• the substrate further including a lithium niobate thin film, wherein the lithium niobate thin film includes a transducer region and a tapered transition region that are etched, the sub-wavelength acoustic waveguide, an acoustic-photonic crystal cavity, and a side-coupled photonic crystal;
• wherein
• the etched transducer region is provided with an interdigital transducer, the sub-wavelength acoustic waveguide is connected with the etched transducer region via the tapered transition region that is etched, the acoustic-photonic crystal cavity is connected with a non-suspended sub-wavelength acoustic waveguide and is arranged parallel to a suspended side-coupled photonic crystal;
• the interdigital transducer, the tapered transition region, and the sub-wavelength acoustic waveguide are in a non-suspended state relative to the substrate;
• the acoustic-photonic crystal cavity and the side-coupled photonic crystal are in a suspended state relative to the substrate;
• and
• the acoustic-photonic crystal cavity includes periodically varying air holes formed by etching a suspended straight waveguide with identical height and width to the sub-wavelength acoustic waveguide, wherein the air holes include a defect region in a middle and mirror regions on both sides;
• the defect region is configured to confine resonance, and the mirror regions are configured to reflect and enhance the resonance;
• the acousto-optic modulator further includes a microprocessor chip and a monitoring device, and the acoustic-photonic crystal cavity is further integrated with an electro-thermal micro-actuator configured as a micro-electro-mechanical-system (MEMS);
• wherein
• the microprocessor chip is configured to control the MEMS in the acoustic-photonic crystal cavity for heating and determine heating parameters of the MEMS based on sensor data and physical characteristics, wherein
• the sensor data includes a cavity temperature acquired by a temperature sensor, a cavity humidity acquired by a humidity sensor, pressure data acquired by a pressure sensor, or vibration data;
• and
• the physical characteristics include major axis dimensions, dimensions of a minor axis, a count of cells of the defect region and each of the mirror regions of the air holes of the sub-wavelength acoustic waveguide and the acoustic-photonic crystal cavity, an angle of the sub-wavelength acoustic waveguide, a thickness of the lithium niobate thin film, and a thickness of the silicon dioxide layer, a width of the transducer region, a finger width of the interdigital transducer and the number of finger pairs;
• and the monitoring device is configured to acquire the sensor data.