National Taiwan University Dept Elect EngnHo, Keang-PoKeang-PoHo2006-11-142018-07-062006-11-142018-07-062005-04http://ntur.lib.ntu.edu.tw//handle/246246/200611150121691Based on a rigorous model without approximation, the channel capacity is evaluated numerically for intensity-modulated direct-detection systems dominated by optical amplifier noises. With a discrete probability at zero intensity, the optimal input distribution is both discrete and continuously distributed. For small signal-to-noise ratio less than about 5 dB, the optimal signal is binary on–off keying.application/pdf153014 bytesapplication/pdfzh-TWChannel capacitydirect-detectionon–off keyingjournal articlehttp://ntur.lib.ntu.edu.tw/bitstream/246246/200611150121691/1/3619.pdf