Investigation on coarse WDM components and systems for four-channel Multi-Gb/s short-range transmission over 1-mm diameter step-index polymer optical fiber

Inhalt:
The polymer optical fiber (POF) offers certain advantages over alternative data communication media such as glass fibers, copper cables or wireless systems. Due to its advantages, POF is a good candidate for short-range telecommunication networks. Among different types of POF, the standard 1-mm step-index POF (SI-POF) is the best known and by far the most widely used type of POF. However, the SI-POF suffers from high attenuation and strong inter-modal dispersion. To extend the capacity of the SI-POF link multiple optical carriers can be used for parallel transmission of data channels over the same fiber. This paper investigates the potential of coarse wavelength division multiplexing (WDM) technology for Multi-Gb/s short-range transmission over 1-mm SI-POF. In the absence of commercially available components, the key photonic WDM components are realized at the Harz University. For combining the optical signals coming from violet, blue, green, and red laser diodes (LDs) onto 1-mm SI-POF, a 4:1 coupler with low insertion loss (IL) is developed. To spatially separate different wavelength channels, a four-channel demultiplexer (DEMUX) with low IL (< 5.7 dB) and high (non-) adjacent channel isolation (> 30 dB) is realized in the bulk optics technology. For the first time a four-channel Multi-Gb/s transmission is reported over 25 m and 50 m SI-POF link. The non-return-to-zero (NRZ) modulation is used in combination with offline-processed feed-forward equalization (FFE) to demonstrate 10.7 Gb/s four-channel WDM transmission over 25 m SI-POF link at a bit error rate (BER) of less than 10^-3. In addition, the same technique is used to achieve 7.5 Gb/s four-channel WDM transmission over 50 m SI-POF link at a BER of less than 10^-6.