Numerical Calculations are employed to study the modulation of light by surface acoustic waves (SAWs) in photonic band gap (PBG) structures. The on/off contrast ratio in PBG switch based on optical cavity is determined as a function of the SAW induced dielectric modulation. We show that these structures exhibit high contrast ratios even for moderate acousto-optic coupling
We theoretically investigate the use of Rayleigh surface acoustic waves (SAWs) for refractive index modulation in optical waveguides consisting of amorphous dielectrics. Considering low-loss Si$_3$N$_4$ waveguides with a standard core cross section of 4.4$\times$0.03 $μ$m$^2$ size, buried 8 $μ$m deep in a SiO$_2$ cladding we compare surface acoustic wave generation in various different geometries via a piezo-active, lead zirconate titanate film placed on top of the surface and driven via an interdigitized transducer (IDT). Using numerical solutions of the acoustic and optical wave equations, w…
We present a novel approach for temporal contrast enhancement of energetic laserpulses by filtered SPM broadened spectra. A measured temporal contrast enhancement by at least 7 orders of magnitude in a simple setup has been achieved. This technique is applicable to a wide range of laser parameters and poses a highly efficient alternative to existing contrast-enhancement methods.
An opto-electronic radio-frequency oscillator that is based on forward scattering by the guided acoustic modes of a standard single-mode optical fiber is proposed and demonstrated. An optical pump wave is used to stimulate narrowband, resonant guided acoustic modes, which introduce phase modulation to a co-propagating optical probe wave. The phase modulation is converted to an intensity signal at the output of a Sagnac interferometer loop. The intensity waveform is detected, amplified and driven back to modulate the optical pump. Oscillations are achieved at a frequency of 319 MHz, which match…
High-Efficiency Acousto-Optic Modulation on Non-Suspended Thin-Film Lithium Tantalate
University of Science and Technology of China（中国科学技术大学）；Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences（中国科学院上海微系统信息技术研究所）；University of Chinese Academy of Sciences（中国科学院大学）
Tailoring the interaction between light and sound has opened new possibilities in photonic integrated circuits (PICs) that ranges from achieving quantum control of light to high-speed information processing. However, the actuation of sound waves in Si PICs usually requires integration of a piezoelectric thin film. Lead Zirconate Titanate (PZT) is a promising material due to its strong piezoelectric and electromechanical coupling coefficient. Unfortunately, the traditional methods to grow PZT on Silicon are detrimental for photonic applications due to the presence of an optical lossy intermedia…
A highly efficient on-chip acousto-optic modulator, as a key component, occupies an exceptional position in microwave-to-optical conversion. Homogeneous thin-film lithium niobate is preferentially employed to build the suspended configuration forming the acoustic resonant cavity to improve the modulation efficiency of the device. However, the limited cavity length and complex fabrication recipe of the suspended prototype restrain further breakthrough in the modulation efficiency and impose challenges for waveguide fabrication. In this work, based on a nonsuspended thin-film lithium niobate-cha…
Microwave frequency acousto-optic modulation is realized by exciting high overtone bulk acoustic wave resonances (HBAR resonances) in the photonic stack. These confined mechanical stress waves transmit exhibit vertically transmitting, high quality factor (Q) acoustic Fabry Perot resonances that extend into the Gigahertz domain, and offer stress-optical interaction with the optical modes of the microresonator. Although HBAR are ubiquitously used in modern communication, and often exploited in superconducting circuits, this is the first time they have been incorporated on a photonic circuit base…
This paper reviews the application of coherent acoustic phonons in the form of piezoelectrically-generated surface acoustic waves to control the response of integrated photonic acousto-optic waveguide structures. We first address the fundamental properties of the acoustic fields in piezoelectric materials as well as the piezoelectric generation of surface acoustic waves using interdigital transducers. The mechanism responsible for the interaction between light and the acoustic modes in the photonic waveguide structures and the modulation of the response of the devices is carefully reviewed. Ne…
Space-time modulated metamaterials support extraordinary rich applications, such as parametric amplification, frequency conversion and non-reciprocal transmission. However, experimental realization of space-time modulation is highly non-trivial, hindering many interesting physics that are theoretically predicted to be experimentally demonstrated. Here, based on the proposed virtualized metamaterials with software-defined impulse response, we experimentally realize non-Hermitian space-time varying metamaterials for efficient and asymmetric frequency conversion by allowing material gain and loss…
