Fiber optic advances made in the 1980s have revolutionized the concept of telecommunications services and applications. With the development of integrated photonics and deployment of optical technology in many diverse applications, inroad of lightwave systems to traditionally captive arena of alternative technologies has been rather impressive. The 90’s trend to include technologies such as optical amplifiers, DWDM and gratings combined with a variety of new services such as internet, broadband network, and multimedia, can only make this inroad much deeper in the millennium. An ultimate goal, beyond the point-to-point/-multipoint transmission and distribution capability achieved thus far, is to provide a fault-tolerant, reliable connectivity in multi-user networks where the electrical bottlenecks will be avoided altogether by performing all functions, e.g., switching, mux/demux, etc., transparently in the optical domain. Technology for all-optical networking is still evolving with much development and engineering work remaining. These advanced networks based on WDM technology can only be realized to its fullest capability provided appropriate components are developed and tested, and the integrated systems meet specified performance goals. Therefore, the requirements for the production test facility and performance specifications of advanced DWDM networks have become increasingly complex and stringent. This paper reviews the critical requirements and production test issues relevant to DWDM components and networks. Impact of high-tech systems specifications on the quality of components and testability is also addressed.