Transmitter launch power and receiver sensitivity of commercial data link modules as a function of multimode fiber size.

AT&T, Sumitomo and PCO (formerly Plesscor) data link modules were measured for transmitter launch power and receiver sensitivity when used with the five common graded-index multimode fiber types-50micron core diameter/1.1% DELTA, 50micron/1.3%, 62. 5micron/2%, 85 micron/1.8%, and 100micron/2.2%. To varying degrees, all transmitters consistently launched more power into the larger diameter fibers. Receiver sensitivities showed great diversity with some sensitivities increasing with the larger fibers, some showing no change, and some showing a sensitivity threshold at the 62.5micron fiber and then decreasing. When the combined effects of launch power and receiver sensitivity are included, most transmitter/receiver pairs weaken the argument for using 85 and 100micron fibers.