Subscriber loop transmission using low operating current light emitting diodes subjected to temperature extremes

A unique edge-emitting LED has been developed that has characteristics particularly attractive for use in loop transmission equipment. At low operating currents of 20-25 mA, sufficient optical power is launched into a Single-mode fiber to transmit data rates typical of the present day loop plant, 1.5-45 Mbit/s. In the system experiments reported here, 45-Mbit/s data was transmitted 12.9 km while operating the LED at a low drive current of 20-mA peak and at temperatures from -20 to +70°C. These experiments and related analyses confirm that the LED offers a reliable, low cost, and easy to use alternative to diode lasers and high drive current LED's in the telephone loop plant.