David A. B. Miller

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• Ph. D.
• Professor (Full) at Stanford University

This book introduces the modern physics of quantum mechanics and statistical mechanics and their applications. Its approach makes it accessible to a wide range of scientists and engineers. Openly available online videos cover the entire material of the text chapters. A digital version of the book, including links to all videos, is freely available;...

Photonic technologies continue to drive the quest for new optical materials with unprecedented responses. A major frontier in this field is the exploration of nonlocal (spatially dispersive) materials, going beyond the local, wavevector-independent assumption traditionally made in optical material modeling. On one end, the growing interest in plasm...

We demonstrate a silicon photonic architecture comprised of Double Mach-Zehnder Interferometers (DMZIs) designed for high-contrast photonic applications. This configuration significantly enhances the achievable extinction ratio of photonic integrated circuits (PICs), reaching levels exceeding 80 dB. By leveraging the tunable properties of DMZIs and...

We propose an approach to integrated optical spectral filtering that allows arbitrary programmability, can compensate automatically for imperfections in filter fabrication, allows multiple simultaneous and separately programmable filter functions on the same input, and can configure itself automatically to the problem of interest, for example to fi...

The concept of optimal communication channels shapes our understanding of wave-based communication. Its analysis typically focuses on specific communication-domain geometries, however, without a general theory of scaling laws or fundamental limits. In this article, we derive shape-independent bounds on the coupling strengths and information capacit...

Optical modes offer spatial degrees of freedom that can be exploited to implement advanced functionalities across various applications. Conventional photonic devices used for the manipulation of modes operate on predetermined families of eigenmodes of specific systems. Here, we report on a recent finding of our research, where we demonstrate that r...

Applications of waves in communications, information processing and sensing need a clear understanding of how many strongly coupled channels or degrees of freedom exist in and out of volumes of space and how the coupling falls off for larger numbers. Numerical results are possible, and some heuristics exist, but there has been no simple physical pi...

Achieving precise control of light intensity in 3D volumes is highly in demand in many applications in optics. Various wavefront shaping techniques have been utilized to reconstruct a target amplitude profile within a 3D space. However, these techniques are intrinsically limited by cross-talk and often rely on optimization methods to improve the re...

Optical phenomena always display some degree of partial coherence between their respective degrees of freedom. Partial coherence is of particular interest in multimodal systems, where classical and quantum correlations between spatial, polarization, and spectral degrees of freedom can lead to fascinating phenomena (e.g., entanglement) and be levera...

Controlling wave transmission is crucial for various applications. In this work, we apply the concept of unitary control to manipulate multiport wave transmission. Unitary control aims to control the behaviors of a set of orthogonal waves simultaneously. The approach fully harnesses the capability of wavefront shaping techniques, with promising app...

We investigate the majorization order for comparing wave coherence and reveal its fundamental consequences in transport measurements, including power distribution, absorption, transmission, and reflection. We prove that all these measurements preserve the majorization order under unitary control, enabling direct experimental characterization of the...

Pixelated approaches to wavefront sensing and generation are commonplace, but inefficient and present core challenges for development of effective phase array antenna due to the physical limitation in grating coupler placement and 2D Nyquist sampling limits. A major challenge in the use of pixelated PICs for free-space applications is that arrays o...

Entanglement is a unique feature of quantum mechanics. In coupled systems of light and matter, entanglement manifests itself in the linear superposition of multipartite quantum states (e.g., parametrized by the multiple spatial, spectral, or temporal degrees of freedom of a light field). In bipartite systems, the Schmidt decomposition provides a mo...

Programmable photonic integrated processors offer a large potential for the generation, manipulation, and detection of free-space optical beams (FSO). Applications are shown on the automated setting of optimal orthogonal MIMO channels and transmission through time varying FSO links.

We propose and demonstrate the optical inversion of a programmable matrix by using a silicon photonic interferometer mesh in a feedback loop, without any optical-to-electronic conversions inside the inversion process.

We show that self-configuring optical networks can analyze partially incoherent light. We consider the case of N spatial input channels and present a power-optimization method to measure their coherency matrix.

A reconfigurable-SOI-photonics platform capable of dynamically multiplexing and demultiplexing an orthogonal basis of low-loss optical-modes through a 1 km equivalent free-space channel is demonstrated. The channel-defined orthogonal basis is determined by utilizing singular value decomposition.

We demonstrate a holographic technique based on interfering the optimum orthogonal communication modes connecting a source plane and a receiver volume, enabling 3D holography with high resolution, low cross-talk, and realistic depth perception.

Modes of propagation through an optical system are generally defined as the eigensolutions of the wave equation in the system. When propagation occurs through complicated or highly scattering media, however, modes are better identified as the best orthogonal communication channels to send information between sets of input and output apertures. Here...

Optical phase measurement is critical for many applications, and traditional approaches often suffer from mechanical instability, temporal latency, and computational complexity. In this paper, we describe compact phase sensor arrays based on integrated photonics, which enable accurate and scalable reference-free phase sensing in a few measurement s...

Modes of propagation are generally defined as the eigensolutions of the wave equation in a given system. When propagation occurs through complicated or highly scattering media, however, modes are better identified as the best orthogonal communication channels to send information between sets of input and output apertures. Here, we demonstrate that...

Optical phase measurement is critical for many applications and traditional approaches often suffer from mechanical instability, temporal latency, and computational complexity. In this paper, we describe compact phase sensor arrays based on integrated photonics, which enable accurate and scalable reference-free phase sensing in a few measurement st...

As blockchain technology and cryptocurrency become increasingly mainstream, photonic computing has emerged as an efficient hardware platform that reduces ever-increasing energy costs required to verify transactions in decentralized cryptonetworks. To reduce sensitivity of these verifications to photonic hardware error, we propose and experimentally...

Integrated photonic neural networks provide a promising platform for energy-efficient, high-throughput machine learning with extensive scientific and commercial applications. Photonic neural networks efficiently transform optically encoded inputs using Mach-Zehnder interferometer mesh networks interleaved with nonlinearities. We experimentally trai...

This study shows why and when optical systems need thickness as well as width or area. Wave diffraction explains the fundamental need for area or diameter of a lens or aperture to achieve some resolution or number of pixels in microscopes and cameras. This work demonstrates that if we know what the optics is to do, even before design, we can also d...

Programmable feedforward photonic meshes of Mach–Zehnder interferometers are computational optical circuits that have many classical and quantum computing applications including machine learning, sensing, and telecommunications. Such devices can form the basis of energy-efficient photonic neural networks, which solve complex tasks using photonics-a...

Multiple orthogonal free-space optical (FSO) communication channels are automatically established between photonic chips hosting programmable integrated processors. All-optical channel demultiplexing is achieved with a crosstalk < -30 dB even after co-propagation though arbitrary mode mixers.

We demonstrate a 1.12-Tbps error-free data transmission throughout inverse- designed multimode photonic circuits using spectrally flattened microcombs as a multiwavelength laser source.

Phase contrast microscopy has played a central role in the development of modern biology, geology, and nanotechnology. It can visualize the structure of translucent objects that remains hidden in regular optical microscopes. The optical layout of a phase contrast microscope is based on a 4 f image processing setup and has essentially remained uncha...

The use of optical interconnects has burgeoned as a promising technology that can address the limits of data transfer for future high-performance silicon chips. Recent pushes to enhance optical communication have focused on developing wavelength-division multiplexing technology, and new dimensions of data transfer will be paramount to fulfill the e...

Programmable unitary photonic networks that interfere hundreds of modes are emerging as a key technology in energy-efficient sensing, machine learning, cryptography, and linear optical quantum computing applications. In this work, we establish a theoretical framework to quantify error tolerance and scalability in a more general class of "binary tre...

We show why and when optics needs thickness as well as width or area. Wave diffraction explains the fundamental need for area or diameter of a lens or aperture to achieve some resolution or number of pixels in microscopes and cameras. Now we show that, if we know what the optics is to do, even before design, we can also deduce minimum required thic...

Photonic integrated circuits play a pivotal role in many applications. Particularly powerful are circuits based on meshes of reconfigurable Mach–Zehnder interferometers as they enable active processing of light. This meets demands accross different fields, from communication to signal and information processing and sensor applications. Here, we use...

Free-space optics naturally offers multiple-channel communications and sensing exploitable in many applications. The different optical beams will, however, generally be overlapping at the receiver, and, especially with atmospheric turbulence or other scattering or aberrations, the arriving beam shapes may not even be known in advance. We show that...

As blockchain technology and cryptocurrency become increasingly mainstream, ever-increasing energy costs required to maintain the computational power running these decentralized platforms create a market for more energy-efficient hardware. Photonic cryptographic hash functions, which use photonic integrated circuits to accelerate computation, promi...

Neural networks are widely deployed models across many scientific disciplines and commercial endeavors ranging from edge computing and sensing to large-scale signal processing in data centers. The most efficient and well-entrenched method to train such networks is backpropagation, or reverse-mode automatic differentiation. To counter an exponential...

The concept of optimal communication channels shapes our understanding of wave-based communication. Its analysis, however, always pertains to specific communication-domain geometries, without a general theory of scaling laws or fundamental limits. In this article, we derive shape-independent bounds on the coupling strengths and information capaciti...

Photonic integrated circuits (PICs) play a pivotal role in many applications. Particularly powerful are circuits based on meshes of reconfigurable Mach-Zehnder interferometers as they enable active processing of light. Various possibilities exist to get light into such circuits. Sampling an electromagnetic field distribution with a carefully design...

A complete set of online lectures and courses on quantum mechanics is freely available through this link https://web.stanford.edu/group/dabmgroup/cgi-bin/dabm/teaching/quantum-mechanics/ This includes links to two complete open online classes, the lectures themselves (through direct links), copies of lecture slides, and frequently-asked question...

We propose LightHash , the first feasible photonic cryptographic hash function for blockchain technology using programmable photonic networks. We experimentally evaluate LightHash and assess whether photonic circuits can outperform digital competitors in latency and energy efficiency.

We demonstrate 130 Gbps transmission in each of 4 spatial modes using Si 3 N 4 soliton microcombs and inverse-designed silicon mode multiplexers. Out of 52 carriers, 42 data channels show natively error-free data transmission.

We demonstrate 130 Gbps transmission in each of 4 spatial modes using Si 3 N 4 soliton microcombs and inverse-designed silicon mode multiplexers. Out of 52 carriers, 42 data channels show natively error-free data transmission.

We experimentally demonstrate in situ backpropagation in a programmable nanophotonic interferometer network, achieving inference accuracies matching digital implementations. Error gradients are computed by simultaneously measuring optical interference at intermediate network components, eliminating expensive digital computations.

Silicon photonics allows remarkably complex interferometric optical circuits. Novel algorithms and architectures, including self-configuring and self-stabilizing approaches, can control these, enabling new functions and applications, and a new class of programmable optical components and systems.

A pair of self-configuring Mach-Zehnder based meshes controlling arrayed optical antennas is exploited to establish chip-to-chip free-space communication using multiple orthogonal beams. The link is automatically established and preserves more than 30-dB rejection between channels.

We propose a new free-space mode-sorter that can distinguish 15 spatial-modes with high efficiency, high fill factor and low crosstalk in non-perfect optical systems through the integrations of custom mode filter coupled with software-controllable photonic-mesh.

The introduction of piezo-optomechanical phase shifters into silicon optical chips enables the realization of complex, controllable optical processing circuits with negligible static power dissipation, high-speed configuration and compatibility with wafer-scale fabrication.

Free-space optics (FSO) is an attractive technology to meet the ever-growing demand for wireless bandwidth in next generation networks. To increase the spectral efficiency of FSO links, transmission over spatial division multiplexing (SDM) can be exploited, where orthogonal light beams have to be shaped according to suitable amplitude, phase, and p...

A video of this talk is available at https://youtu.be/Mn6WER1bNJc Technologies like silicon photonics allow complex optics. Emerging applications in communications, sensing, and classical and quantum information processing demand complex controllable circuits. Recent advances in novel interferometric mesh architectures, new algorithmic approaches...

In technologies operating at light wavelengths for wireless communication, sensor networks, positioning, and ranging, a dynamic coherent control and manipulation of light fields is an enabling element for properly generating and correctly receiving free-space optical (FSO) beams even in the presence of unpredictable objects and turbulence in the li...

Free-space optics (FSO) offer promising solutions in wireless systems where many different devices need to communicate and interoperate, exchanging massive amounts of data as in communication and sensor networks, and in technologies for positioning and ranging. In these applications, control and manipulation of the light field is required for prope...

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 th...

Just as “classical” information technology rests on a foundation built of interconnected information-processing systems, quantum information technology (QIT) must do the same. A critical component of such systems is the “interconnect,” a device or process that allows transfer of information between disparate physical media, for example, semiconduct...

We study dispersion models and design variations for programmable MEMS photonic networks to analyze scalability of parallel matrix-vector multiplication, which is a core element of commercially viable and energy-efficient photonic neural network accelerator chips.

We showcase the application of resonant flat optical elements as insertable angular filters that facilitate phase contrast imaging. With high accuracy direct angular filtering, quantitative phase contrast imaging is achieved akin to Fourier optics approaches.

We propose an optical proof-of-work scheme that feeds data encoded into wavelength-division multiplexed modes through a programmable photonic network. We verify robustness by modeling network dispersion, allowing for energy-efficient optical al- ternatives to current cryptocurrency security schemes.

Optical physics and well-chosen intimately-integrated devices allow dense, low-energy communications if we also use optical parallelism and timing precision to eliminate most receiver, time-multiplexing and timing circuits that otherwise dissipate most of the energy.

Technologies like silicon photonics allow complex optics. Emerging applications in communications, sensing, and classical and quantum information processing demand complex controllable circuits. Recent advances in novel interferometric mesh architectures, new algorithmic approaches to control, including self-configuring and self-stabilizing circuit...

Artificial intelligence tasks across numerous applications require accelerators for fast and low-power execution. Optical computing systems may be able to meet these domain-specific needs but, despite half a century of research, general-purpose optical computing systems have yet to mature into a practical technology. Artificial intelligence inferen...

We show a new way of thinking about optics. This way of thinking lets us make kinds of optics we did not know how to make before. It can be implemented in silicon photonics, and taken together with new architectures and algorithms, we can work with much more complicated photonic integrated circuits, enabling those new optics. Some circuits can even...

The video of this talk is available at https://youtu.be/-qkGelIyPR8 . A combination of complex meshes of interferometers with photodetectors and simple feedback loops allows sophisticated photonic systems to configure and stabilize themselves without calibration, and they can be directly, progressively and adaptively trained to perform arbitrary li...

The video of this talk is available at https://youtu.be/XUfd45590eA .We argue we can substantially reduce energy dissipation and increase interconnect bandwidth density using parallel synchronous free-space optical channels inside and between racks, exploiting integrated waveguide photonics, and avoiding power-hungry time-multiplexing. This talk is...

The growing maturity of integrated photonic technology makes it possible to build increasingly large and complex photonic circuits on the surface of a chip. Today, most of these circuits are designed for a specific application, but the increase in complexity has introduced a generation of photonic circuits that can be programmed using software for...

The video of this talk is available at https://youtu.be/6PMOubyjvpk We show a simple and rigorous way of finding the strongest and lowest cross-talk channels for communicating with optics. This approach leads to several practical and fundamental results in classical and quantum optics. This work is mostly based on the paper "Waves, modes, communi...

Working with finite numbers of modes to describe, generate, and detect optical fields can be both mathematically economical and physically useful. Such a modal basis can map directly to various applications in communications, sensing, and processing. But, we need a way to generate and analyze such fields, including measurement and control of both t...

Reconfigurable photonic mesh networks of tunable beamsplitter nodes can linearly transform $N$ -dimensional vectors representing input modal amplitudes of light for applications such as energy-efficient machine learning hardware, quantum information processing, and mode demultiplexing. Such photonic meshes are typically programmed and/or calibrat...

Working with finite numbers of modes to describe, generate and detect optical fields can be both mathematically economical and physically useful. Such a modal basis can map directly to various applications in communications, sensing and processing. But, we need a way to generate and analyze such fields, including measurement and control of both the...

We argue energy and interconnect density in information processing can be improved by orders of magnitude using parallel free-space optical channels inside and between racks, enabled by integrated waveguide photonics, and run synchronously without time-multiplexing.

We propose and numerically demonstrate a fault-tolerant, efficient parallel nullification protocol to program and error-correct photonic neural networks for energy- efficient machine learning tasks.

We argue we can substantially reduce energy dissipation and increase interconnect bandwidth density using parallel synchronous free-space optical channels inside and between racks, exploiting integrated waveguide photonics, and avoiding power-hungry time-multiplexing.

We report on the automated control of self-configuring programmable photonics meshes employed for the manipulation of free-space optical beams. Applications include optical beam coupling and identification, phase front correction and transmission through scattering media.

We show a simple and rigorous way of finding the strongest and lowest cross-talk channels for communicating with optics. This approach leads to several practical and fundamental results in classical and quantum optics.

A Mach-Zehnder mesh (MZM), which is comprised of a network of tunable 2 × 2 Mach-Zehnder interferometers and embedded photodetectors (PDs), can be used to perform arbitrary unitary matrix multiplications in the optical domain and compensate modal crosstalk in short-reach mode-divisionmultiplexed (MDM) links that use direct detection (DD). MZMs can...