Coarse WDM: A way to increase the transmission capacity of a 1-mm diameter step index polymer optical fiber

This paper employs the wavelength division multiplexing (WDM) technology to overcome the bandwidth limitation and increase the transmission capacity of a 1-mm diameter step-index polymer optical fiber (SI-POF). A four-channel laser diode-based transmission system operating at 405, 450, 514, and 639 nm has been realized with low-loss WDM components developed at the Harz University. The non-return-to-zero modulation has been used in combination with offline-processed feed-forward equalization to demonstrate the 7.8 Gb/s data transmission over 50-m SI-POF at a bit error rate (BER) lower than 10-5. In addition, the same technique has been applied to realize the 3.21 Gb/s transmission over 100-m SI-POF (BER<10-4).