The effects of PMD in buried and aerial single mode and polarization maintaining fibers and performance of direct and external modulation techniques at high speed data rate

Abstract

Optical fiber transmission is greatly affected by dispersion and in this study, we experimentally investigate angular displacement and speed of state of polarization in Single Mode Fibers (SMF) and Polarization Maintaining Fibers (PMF) in two states, i.e. aerial and buried state. The results show that a buried single mode fiber incurs minimal change of state of polarization (implying lower polarization mode dispersion) as compared to a buried polarization maintaining fiber, with a slight difference of 0.000464 standard deviation (spread). This is a good finding, since, most of the telecom companies use single mode fibers for their transmission, so reinstallation might be so costly, time wasting and unnecessary as well as the costs that would be incurred in purchasing polarization maintaining fibers which are more expensive compared to the single mode fiber, as per ‘THORLABS’. That is, $33.75–$40.0 per meter of PMF compared to $7.0–$14.0 per meter of a single mode fiber. However, in cases where aerial transmissions are un-avoidable, polarization maintaining fibers are highly recommended as compared to single mode fibers. The overwhelming increase in the bandwidth demand as the number of people with smartphones and other internet-using gadgets shoots up, numerous apps (some with an aspect of live streaming), social media platforms, broadcasting networks, has created a bottle-neck in the telecommunication. Measures put in place include recent digital migration, which arose out of the Regional Radio Communication Conference of 2006 (RRC06) and the subsequent Geneva 2006 Agreement (GE06) of the International Telecommunication Union (ITU) ‘Recommendations’ which resolved that all countries signatory to the agreement must migrate from analogue to digital broadcasting services by 2015 (Uganda was part). This does not solve the problem of increased required capacity; therefore, we experimated 10Gbps VCSEL data transmissions using high-speed data modulation techniques i.e. direct and amplitude (external). Frequency modulation is the commonly used technique in so many countries like Uganda thus a need to supplement this with other modulation technics like amplitude modulation. In addition, amplitude modulation ensures long distance modulation compared to frequency modulation, with which most radio stations broadcast. The results include direct modulation at different bias currents, different transmission fiber lengths, chromatic dispersion at different transmission widow and corresponding fibers i.e. G655 and G652 single mode fibers and finally amplitude modulation using a Mach-Zander. These technics show the ability to pace with increased capacity demand of over 100Gbps.