By Curt Weinstein, Corning Incorporated
Since 1991, cable television operators have been weighing the relative merits of a new transmission window, the 1550 nanometer (nm) wavelength, versus operating at 1310 nm, where much of the industry's recent transmission efforts have been concentrated.
In conjunction with this, the feasibility of erbium-doped fiber-optic amplifiers (EDFAs) operating at 1550 nm also have been the topic of much discussion. The high output power and minimal distortions of these devices makes them ideal for amplitude modulation (AM) video distribution. As passive optical components, such as low loss, high port count (ie. 1x4, 1x8, and 1x16) splitters and optical amplifiers become commercially available in high volumes, the economic implications of their deployment in cable TV system rebuilds can be compelling.
Fiber-optic amplifiers can reduce the costs of an optical/ink and allow deeper penetration of fiber into the system. Due to the inherently lower attenuation of optical fiber at 1550 nm, nearly 40 percent lower relative to 1310 nm, amplifiers can permit longer fiber runs and increased sharing of transmitters via optical splitting. In addition, because the 1310 nm operating window is not currently utilized in an optical amplifier based system, operators can design their systems to deliver broadcast signals at 1550 nm today with the ability to offer narrowcast services at 1310 nm or other wavelengths in the future.
This paper will discuss the status of passive optical component technologies for splitters and the status of EDFAs. In addition, it will present the current state-of-the-art performance for some of these devices and scenarios for their cost-effective deployment in future applications.