# Overcoming Challenges in Large-Core SI-POF-Based System-Level Modeling and Simulation
## 1 Introduction  
For many years now, researchers across the globe have been reporting experiments demonstrating the feasibility of transmitting high-speed data over different types of plastic optical fibers (POFs). Due to the high-loss of POF (\(\sim\)100-300 dB/km), its application was discussed in the context of short-reach in-home [1; 2] and automotive networks [3]. More recently, POF has been suggested as a transmission medium for avionic platforms as well [4]. While the experimental results are quite impressive, the modeling and simulation of POF links have not kept pace; commercial software packages have only recently begun to add support for system-level modeling of POFs. POF-based communication systems are usually operated close to their capacity, which is limited by the scarce power budget, the reduced bandwidth or a combination of both. Moreover, the growing demand for higher data rates is challenging the capability of SI-POFs to supply enough bandwidth even in these restricted environments and is compelling researchers to investigate different technologies to enhance spectral efficiency [5; 6; 7; 8; 9]. Therefore, it is essential that the system performance using new transmission techniques be estimatedand the design be optimized before the system is physically deployed. The tight power budget and multiple components comprising the POF-based system make the use of a rigorous, experimentally validated simulation framework, with proven predictive capabilities, a crucial tool in assessing the end-to-end system performance. There are a few different types of POFs available in the market whose key distinguishing features lay in the properties of the material used for the core and cladding (related to the refractive index profile), the diameter of an individual core, the number of cores, and the refractive index profile. Each POF type possesses a set of unique characteristics that makes it particularly suitable for specific data network scenarios [10]. For short-range data transmission, the step-index plastic optical fiber (SI-POF) is a competitive media for low-cost applications. Although, recently, multicore step-index plastic optical fiber (MC SI-POF) and graded-index plastic optical fiber (GI-POF) have garnered attention due to their potentially greater bandwidths. Although poly-methyl methacrylate (PMMA)-based POF exhibits its best transmission performance when operating at the visible end of the spectrum, supporting red and green light sources, its attenuation is often higher than can be tolerated by some applications. Thus, researchers have been working on alternatives that inherently have lower loss and support transmission in the infrared region of the spectrum, where high-quality light sources are more readily available. Partially fluorinated methacrylate polymer such as poly (2,2,2-trifluoroethyl methacrylate) (P3 FMA)-based GI-POF, with an attenuation coefficient of 71 dB/km, was shown to be superior to the PMMA-based POF, not only in terms of lower attenuation but also due to its lower modal dispersion [11]. Perfluorinated graded-index plastic optical fiber (PF GI-POF) with a core diameter of 50-120 \(\upmu\)m is emerging with even better performance than the P3 FMA. Losses of 50 dB/km and lower in the wavelength range 600-1300 nm are now being realized [12; 13]. Over the years, different approaches to simulate optical power transmission in large-core POFs have been devised in an attempt to achieve a compromise between precision and computation time. Ray-tracing provides a highly intuitive approach that has been successfully applied to describe light propagation not only in SI-POFs [14], but also in MC-POFs and GI-POFs [15; 16; 17] and has also been adapted to research the effects of perturbations on light transmission [18]. While ray-tracing is flexible to incorporate constraints that describe different situations, its obvious drawback is the required computational time that prevents its use for system-level simulations.