Edward Fisher

University of Edinburgh

Dr. Fisher is a post-doctoral researcher at Edinburgh University. His interests include tomography, digital signal processing and instrumentation for metrology and imaging. He is a fellow of the Software Sustainability Institute, promoting best-practices for embedded software and signal processing firmware. While his current work focuses on logic synthesis for FPGAs, he developed an all-digital array of single-photon avalanche diodes (SPADs) with a readout suitable for optical communications or metrology as a direct optical to digital converter. He has recently completed a historical analysis of avalanche multiplication and the internal photoelectric effect covering the period 1900 to 1969. He is a member of the Institute of Electrical and Electronics Engineers (IEEE), where he serves on the committee for the Sensors Council UK&I chapter and peer-reviews for Transactions on Circuits and Systems.

1books edited

3chapters authored

Latest work with IntechOpen by Edward Fisher

The field of application-specific integrated circuits (ASICs) is fast-paced being at the very forefront of modern nanoscale fabrication—and presents a deeply engaging career path. ASICs can provide us with high-speed computation in the case of digital circuits. For example, central processing units, graphics processing units, field-programmable gate arrays, and custom-made digital signal processors are examples of ASICs and the transistors they are fabricated from. We can use that same technology—complementary metal-oxide semiconductor processes—to implement high-precision sensing of or interfacing to the world through analog-to-digital converters, digital-to-analog converters, custom image sensors, and highly integrated micron-scale sensors such as magnetometers, accelerometers, and microelectromechanical machines. ASIC technologies—now transitioning toward magneto-resistive and phase-changing materials—also offer digital memory capacities that have aided our technological progress. Combining these domains, we have moved toward big data analytics and the new era of artificial intelligence and machine learning. This book provides a small selection of chapters covering aspects of ASIC development and the surrounding business model.

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Application Specific Integrated Circuits

Edited by Edward Fisher

Chapters authored

Single-Photon Avalanche Diodes in CMOS Technologies for Optical Communications

By Edward M.D. Fisher

As optical communications may soon supplement Wi-Fi technologies, a concept known as visible light communications (VLC), low-cost receivers must provide extreme sensitivity to alleviate attenuation factors and overall power usage within communications link budgets. We present circuits with an advantage over conventional optical receivers, in that gain can be applied within the photodiode thus reducing the need for amplification circuits. To achieve this, single-photon avalanche diodes (SPADs) can be implemented in complementary metal-oxide-semiconductor (CMOS) technologies and have already been investigated in several topologies for VLC. The digital nature of SPADs removes the design effort used for low-noise, high-gain but high-bandwidth analogue circuits. We therefore present one of these circuit topologies, along with some common design and performance metrics. SPAD receivers are however not yet mature prompting research to take low-level parameters up to the communications level.

Part of the book: Optical Communication Technology

Principles and Early Historical Development of Silicon Avalanche and Geiger-Mode Photodiodes

By Edward M.D. Fisher

The historical development of technology can inform future innovation, and while theses and review articles attempt to set technologies and methods in context, few can discuss the historical background of a scientific paradigm. In this chapter, the nature of the photon is discussed along with what physical mechanisms allow detection of single-photons using solid-state semiconductor-based technologies. By restricting the scope of this chapter to near-infrared, visible and near-ultraviolet detection we can focus upon the internal photoelectric effect. Likewise, by concentrating on single-photon semiconductor detectors, we can focus upon the carrier-multiplication gain that has allowed sensitivity to approach the single-photon level. This chapter and the references herein aim to provide a historical account and full literature review of key, early developments in the history of photodiodes (PDs), avalanche photodiodes (APDs), single-photon avalanche diodes (SPADs), other Geiger-mode avalanche photodiodes (GM-APDs) and silicon photo-multipliers (Si-PMs). As there are overlaps with the historical development of the transistor (1940s), we find that development of the p-n junction and the observation of noise from distinct crystal lattice or doping imperfections – called “microplasmas” – were catalysts for innovation. The study of microplasmas, and later dedicated structures acting as known-area, uniform-breakdown artificial microplasmas, allowed the avalanche gain mechanism to be observed, studied and utilised.

Part of the book: Photon Counting

Introductory Chapter: ASIC Technologies and Design Techniques

By Edward M.D. Fisher

Part of the book: Application Specific Integrated Circuits

Edward Fisher

Latest work with IntechOpen by Edward Fisher

Application Specific Integrated Circuits

Chapters authored

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