Half-duplex optical transmission link using an LED source–detector scheme

Half-duplex transmission over a single optical fiber using an LED source–detector (LED-DET) scheme, that is, LED's being used both as light sources and as photodetectors, has been demonstrated. The effective quantum efficiency in the detector mode, including optical power coupling from the fiber, was measured to be 18%, which is compared with the furcation loss in the conventional duplex transmission system using optical directional couplers. It is shown that we can realize a more economical, high-performance, half-duplex data transmission system by using an LED-DET scheme.