Multi-Channel Signal Generator ASIC for Acoustic Holograms

A CMOS application-specific integrated circuit (ASIC) has been developed to generate arbitrary, dynamic phase patterns for acoustic hologram applications. An experimental prototype has been fabricated to demonstrate phase shaping. It comprises a cascadable 1 × 9 array of identical, independently-controlled signal generators implemented in a 0.35 μ m minimum feature size process. It can individually control the phase of a square wave on each of the nine output pads. The footprint of the integrated circuit is 1175 × 88 μ m2. A 128 MHz clock frequency is used to produce outputs at 8 MHz with phase resolution of 16 levels (4-bit) per channel. A 6 × 6 air-coupled matrix array ultrasonic transducer was built and driven by four ASICs, with the help of commercial buffer amplifiers, for the application demonstration. Acoustic pressure mapping and particle manipulation were performed. Additionally, a 2 × 2 array piezoelectric micromachined ultrasonic transducer (PMUT) was connected and driven by four output channels of a single ASIC, demonstrating the flexibility of the ASIC to work with different transducers and the potential for direct integration of CMOS and PMUTs

Interface between path and orbital angular momentum entanglement for high-dimensional photonic quantum information

Photonics has become a mature field of quantum information science, where integrated optical circuits offer a way to scale the complexity of the set-up as well as the dimensionality of the quantum state. On photonic chips, paths are the natural way to encode information. To distribute those high-dimensional quantum states over large distances, transverse spatial modes, like orbital angular momentum possessing Laguerre Gauss modes, are favourable as flying information carriers. Here we demonstrate a quantum interface between these two vibrant photonic fields. We create three-dimensional path entanglement between two photons in a nonlinear crystal and use a mode sorter as the quantum interface to transfer the entanglement to the orbital angular momentum degree of freedom. Thus our results show a flexible way to create high-dimensional spatial mode entanglement. Moreover, they pave the way to implement broad complex quantum networks where high-dimensionally entangled states could be distributed over distant photonic chips