Free Space Laser Communicator Using Commercially Available Off the Shelf Components and Frequency Shift Keying Concepts

Abstract

With the rapid increase of file size and users, the current wireless data transfer networks are facing massive demands for channels, but if one wants to implement a RF wireless network one must pay a large fee to the government. Free space laser communication has the promise of mitigating some of these demands using line of sight implementations. OOK (On-Off Keying) is the most popular modulation scheme in free space laser communication; however, the loss of a large part of its transmitted power causes low SNR (signal to noise ratio) in this modulation scheme. This is its main drawback, which limits the maximum distance a free space laser communicator can reliably work. FSK (Frequency Shift Keying) has the advantage over OOK in terms of susceptibly to noise. In this paper we will describe the process of making an affordable free space laser communicator using BFSK (Binary FSK) concepts and commercially available off the shelf components. Because we implemented BFKS instead of OOK this communicator is inherently more resistant to noise and other interference.