arXiv subjects

Dries Vercruysse

Publications and source records attributed to Dries Vercruysse.

8 recordsLinked to original sources

arXiv2021

Inverse-designed multi-dimensional silicon photonic transmitters

Modern microelectronic processors have migrated towards parallel computing architectures with many-core processors. However, such expansion comes with diminishing returns exacted by the high cost of data movement between individual processors. The use of optical interconnects has burgeoned as a promising technology that can address the limits of this data transfer. While recent pushes to enhance optical communication have focused on developing wavelength-division multiplexing technology, this approach will eventually saturate the usable bandwidth, and new dimensions of data transfer will be paramount to fulfill the ever-growing need for speed. Here we demonstrate an integrated intra- and inter-chip multi-dimensional communication scheme enabled by photonic inverse design. Using inverse-designed mode-division multiplexers, we combine wavelength- and mode- multiplexing and send massively parallel data through nano-photonic waveguides and optical fibres. Crucially, as we take advantage of an orthogonal optical basis, our approach is inherently scalable to a multiplicative enhancement over the current state of the art.

physics.app-ph↗

arXiv2021

Inverse-Designed Photonic Crystal Circuits for Optical Beam Steering

The ability of photonic crystal waveguides (PCWs) to confine and slow down light makes them an ideal component to enhance the performance of various photonic devices, such as optical modulators or sensors. However, the integration of PCWs in photonic applications poses design challenges, most notably, engineering the PCW mode dispersion and creating efficient coupling devices. Here, we solve these challenges with photonic inverse design, and experimentally demonstrate a slow-light PCW optical phased array (OPA) with a wide steering range. Even and odd mode PCWs are engineered for a group index of 25, over a bandwidth of 20nm and 12nm, respectively. Additionally, for both PCW designs, we create strip waveguide couplers and free-space vertical couplers. Finally, also relying on inverse design, the radiative losses of the PCW are engineered, allowing us to construct OPAs with a 20° steering range in a 20nm bandwidth.

physics.optics↗

arXiv2019

Nanophotonic Inverse Design with SPINS: Software Architecture and Practical Considerations

A computational nanophotonic design library for gradient-based optimization called SPINS is presented. Borrowing the concept of computational graphs, SPINS is a design framework that emphasizes flexibility and reproducible results. The mathematical and architectural details to achieve these goals are presented, and practical considerations and heuristics for using inverse design are discussed, including the choice of initial condition and the landscape of local minima.

physics.app-ph↗

arXiv2019

Inverse-Designed Diamond Photonics

Diamond hosts optically active color centers with great promise in quantum computation, networking, and sensing. Realization of such applications is contingent upon the integration of color centers into photonic circuits. However, current diamond quantum optics experiments are restricted to single devices and few quantum emitters because fabrication constraints limit device functionalities, thus precluding color center integrated photonic circuits. In this work, we utilize inverse design methods to overcome constraints of cutting-edge diamond nanofabrication methods and fabricate compact and robust diamond devices with unique specifications. Our design method leverages advanced optimization techniques to search the full parameter space for fabricable device designs. We experimentally demonstrate inverse-designed photonic free-space interfaces as well as their scalable integration with two vastly different devices: classical photonic crystal cavities and inverse-designed waveguide-splitters. The multi-device integration capability and performance of our inverse-designed diamond platform represents a critical advancement toward integrated diamond quantum optical circuits.

physics.app-ph↗

arXiv2019

On-chip integrated laser-driven particle accelerator

Particle accelerators represent an indispensable tool in science and industry. However, the size and cost of conventional radio-frequency accelerators limit the utility and reach of this technology. Dielectric laser accelerators (DLAs) provide a compact and cost-effective solution to this problem by driving accelerator nanostructures with visible or near-infrared (NIR) pulsed lasers, resulting in a 10$^4$ reduction of scale. Current implementations of DLAs rely on free-space lasers directly incident on the accelerating structures, limiting the scalability and integrability of this technology. Here we present the first experimental demonstration of a waveguide-integrated DLA, designed using a photonic inverse design approach. These on-chip devices accelerate sub-relativistic electrons of initial energy 83.4 keV by 1.21 keV over 30 um, providing peak acceleration gradients of 40.3 MeV/m. This progress represents a significant step towards a completely integrated MeV-scale dielectric laser accelerator.

physics.app-ph↗

arXiv2019

Inverse-designed photonic circuits for fully passive, bias-free Kerr-based nonreciprocal transmission and routing

Nonreciprocal devices such as isolators and circulators are key enabling technologies for communication systems, both at microwave and optical frequencies. While nonreciprocal devices based on magnetic effects are available for free-space and fibre-optic communication systems, their on-chip integration has been challenging, primarily due to the concomitant high insertion loss, weak magneto-optical effects, and material incompatibility. We show that Kerr nonlinear resonators can be used to achieve all-passive, low-loss, bias-free, broadband nonreciprocal transmission and routing for applications in photonic systems such as chip-scale LIDAR. A multi-port nonlinear Fano resonator is used as an on-chip, all-optical router for frequency comb based distance measurement. Since time-reversal symmetry imposes stringent limitations on the operating power range and transmission of a single nonlinear resonator, we implement a cascaded Fano-Lorentzian resonator system that overcomes these limitations and significantly improves the insertion loss, bandwidth and non-reciprocal power range of current state-of-the-art devices. This work provides a platform-independent design for nonreciprocal transmission and routing that are ideally suited for photonic integration.

physics.optics↗

arXiv2019

Inverse design and demonstration of broadband grating couplers

We present a gradient-based optimization strategy to design broadband grating couplers. Using this method, we are able to reach, and often surpass, a user-specified target bandwidth during optimization. The designs produced for 220 nm silicon-on-insulator are capable of achieving 3 dB bandwidths exceeding 100 nm while maintaining central coupling efficiencies ranging from -3.0 dB to -5.4 dB, depending on partial-etch fraction. We fabricate a subset of these structures and experimentally demonstrate gratings with 3 dB bandwidths exceeding 120 nm. This inverse design approach provides a flexible design paradigm, allowing for the creation of broadband grating couplers without requiring constraints on grating geometry.

physics.app-ph↗

arXiv2017

Fully-automated optimization of grating couplers

We present a gradient-based algorithm to design general 1D grating couplers without any human input from start to finish, including a choice of initial condition. We show that we can reliably design efficient couplers to have multiple functionalities in different geometries, including conventional couplers for single-polarization and single-wavelength operation, polarization-insensitive couplers, and wavelength-demultiplexing couplers. In particular, we design a fiber-to-chip blazed grating with under 0.2 dB insertion loss that requires a single etch to fabricate and no back-reflector.

physics.app-ph↗