 fiber) and they might look for an alternative solution in the event that there is a fiber outage. FSO would be the perfect candidate for such applications because it can offer OC-x-equivalent bandwidth. An FSO network can be deployed in a week or two. However, FSO can rarely be considered the primary solution for these large customers, and this significantly hinders its demand growth. 9.5.2 Economy The economy of a business environment can greatly affect the future of FSO. Back in early 1999, the e-commerce and Internet industries experi- enced explosive growth due to the tremedous bandwidth demand by both e-commerce and online companies. This growth triggered the rapid deploy- ment of new fiber-optic systems across the United States. In contrast, toward the end of 2000 and early 2001, the failure of online companies and the general economic slowdown had left these new fiber-optic systems unused even through the latter part of 2001. Most enterprise customers even scaled back their traffic demand projection from an OC level to a DS3 or T1 level. This economic trend significantly impacted the demand of a broadband optical wireless solution such as FSO because these customers were left with a lot of fiber-based bandwidth and did not know what to do with it. Similar to other emerging technologies, FSO can have a bright future due to its flexibility, scalability, and relative low cost. However, as pointed out earlier, the challenges that FSO faces could overcome all the promising attributes and eventually cause this technology to phase out. Free-Space Optics (FSO) End Notes 1. This chapter was first developed by Kenneth Wong in the summer of 2001 for Professor Minoli's graduate class at the Stevens Institute of Technology. 2. AirFiber Tutorial, "General Technology Overview," http://www.airfiber.com/products/faq/Html/helpset.htm. 3. Terabeam, "Terabeam: Our Technology: Last Mile," http://www.terabeam.com/our/our_net.shtml, 4. Paul F. Szajowski, Gerald Nykolak, James J. Auborn, Herman M. Presby, G. E. Tourgee, and Denn