Fiber Optics Installer and Technician Guide

In Chapter 1, History of Fiber Optics we introduced you to the fiber optic receiver. The job of the receiver is to take light energy from the optical fiber and convert it to electrical energy. In this chapter, we will explain the basic components that make up the fiber optic receiver, starting with the photodiode. You will learn about the effects of optical input power on the performance of the receiver and the performance characteristics of LED and laser receivers.
A photodiode in a fiber optic receiver is like the tire on your car. The photodiode is where the rubber meets the road. Light energy from the optical fiber stops at the photodiode. It's the job of the photodiode to convert the light energy received from the optical fiber into electrical energy. There are different performance-level tires that you can put on your car and there are different performance-level photodiodes that can be incorporated into a receiver. This section of the chapter discusses the fundamentals of basic photodiode operation and the different types of photodiodes that may be used in a receiver.
The best way to imagine a photodiode is to think about a solar cell. We have all seen the exhibits at museums where a solar cell or a group of solar cells powers a small boat or car with the light energy from a light bulb. Maybe you own a solar charger for your boat battery or have decorative outdoor lighting that uses solar...