3 research outputs found
Bidirectional microwave-optical transduction based on integration of high-overtone bulk acoustic resonators and photonic circuits
Coherent interconversion between microwave and optical frequencies can serve
as both classical and quantum interfaces for computing, communication, and
sensing. Here, we present a compact microwave-optical transducer based on
monolithic integration of piezoelectric actuators atop silicon nitride photonic
circuits. Such an actuator directly couples microwave signals to a
high-overtone bulk acoustic resonator defined by the suspended silica cladding
of the optical waveguide core, which leads to enhanced electromechanical and
optomechanical couplings. At room temperature, this triply resonant
piezo-optomechanical transducer achieves an off-chip photon number conversion
efficiency of -48 dB over a bandwidth of 25 MHz at an input pump power of 21
dBm. The approach is scalable in manufacturing and, unlike existing
electro-optic transducers, does not rely on superconducting resonators. As the
transduction process is bidirectional, we further demonstrate synthesis of
microwave pulses from a purely optical input. Combined with the capability of
leveraging multiple acoustic modes for transduction, the present platform
offers prospects for building frequency-multiplexed qubit interconnects and for
microwave photonics at large
A heterogeneously integrated lithium niobate-on-silicon nitride photonic platform
The availability of thin-film lithium niobate on insulator (LNOI) and advances in processing have led to the emergence of fully integrated LiNbO3 electro-optic devices. Yet to date, LiNbO3 photonic integrated circuits have mostly been fabricated using non-standard etching techniques and partially etched waveguides, that lack the reproducibility achieved in silicon photonics. Widespread application of thin-film LiNbO3 requires a reliable solution with precise lithographic control. Here we demonstrate a heterogeneously integrated LiNbO3 photonic platform employing wafer-scale bonding of thin-film LiNbO3 to silicon nitride (Si3N4) photonic integrated circuits. The platform maintains the low propagation loss (<0.1 dB/cm) and efficient fiber-to-chip coupling (<2.5 dB per facet) of the Si3N4 waveguides and provides a link between passive Si3N4 circuits and electro-optic components with adiabatic mode converters experiencing insertion losses below 0.1 dB. Using this approach we demonstrate several key applications, thus providing a scalable, foundry-ready solution to complex LiNbO3 integrated photonic circuits.ISSN:2041-172