Optical CPU Design

This course introduces the student to Digital Photonics. I have kept everything simple and to the point with a description of just a 4-bit optical CPU. Thus, the registers with parallel load don’t use specialized circuitry for parallel load; I just clock the clock line when needed in order to load values into a D-type Register. This is naïve, but the circuit works with slight nuances.

The goal of this course is to show the student a basic optical CPU to show it works and to describe in detail the workings, including a scalable and possibly reusable micro-programmable optical control unit.

The optical control unit uses a basic setup, which is a mapping ROM attached to a presettable binary counter attached to a control ROM, of which the outputs are programmed and map to various circuits for clocking or for setting a multiplexer or demultiplexer, etc. The component count, including optical waveguides and pivot points, is around 1000 components.

This course was a journey for me into optical circuit design with my own self-designed Digital Photonic simulation software. I am sharing my first journey with the software, which is a basic 4-bit optical CPU. The hobby software took about 6 long years to design, and this circuit was used to test the software. I hope the course satisfies your curiosity of digital Photonics.

You should note that with this simulator, I use proof of concept algorithms where a high intensity maps to a logic 1 and a low intensity maps to a logic 0. Thus, at a high level, the hardware algorithm can be shown to work. This is similar to Digital Electronics, but in the optical domain.