 Mbytes by 3. This is because it takes 3 bytes to represent 24-color bits. Doing SO, we obtain both a data storage and data transmission require- ment for 4.638 Mbytes of data. Although virtually all digital cameras use JPEG (Joint Photographic Experts Group) compression to reduce the storage requirements of pictures, in all probability the color photo- graph will be approximately 100 kbytes or more in size. If we compare that size to the 4-kbyte text-based report, we can note that just one pho- tograph represents 25 times the storage and transmission requirements of the prior report. While this author could go on and provide many additional examples, like Indiana Jones, he will simply say "trust me" when referring to the fact that the explosion in the use of digital cam- eras, MP3 audio players, imbedded graphics in documents, and similar multimedia developments has resulted in a considerable increase in communications traffic, which became a driving force for WDM and its evolution into dense WDM. Fiber in the WAN EXPANDING CAPACITY Considering the accelerating growth in data transmission, it was a foregone conclusion that communications carriers needed additional capacity. When considering adding capacity to their infrastructure, communications carriers had four basic options: 1. When optical fiber was initially installed, most cables included a bundle of fibers, some of which were not immediately used and which are referred to as "dark fiber." Thus, one option that a commu- nications carrier could consider was to illuminate existing dark fiber. 2. A communications carrier could also consider upgrading the trans- mission rate of existing optical fiber. For example, OC-48 operating at 2.5 Gbits/s could be upgraded to OC-192 operating at 10 Gbits/s. Unfortunately, upgrading the speed of an optical fiber is not a simple process. The ability to upgrade the transmission rate of a fiber depends first and foremost on the type of fiber. If the fiber was installed over the past few years, it is more than likely low-disp