POF misalignment model based on the calculation of the radiation pattern using the Hankel transform

Abstract

Here, we propose a method to estimate misalignment losses that is based on the calculation of the radiated angular power distribution as light propagates through space using the fiber far field pattern (FFP) and simplifying and speeding calculations with the Hankel transform. This method gives good estimates for combined transversal and longitudinal losses at short, intermediate and long offset distances. In addition, the same methodology can be adapted to describe not only scalar loss but also its angular dependence caused by misalignments. We show that this approach can be applied to upgrade a connector matrix included in a propagation model that is integrated into simulation software. This way, we assess the effects of misalignments at different points in the link and are able to predict the performance of different layouts at system level.

Overcoming Challenges in Large-Core SI-POF-Based System-Level Modeling and Simulation

“…Allowing system designers to estimate the dynamic effects of relevant environmental and operational conditions such as temperature, vibration, stress and dust is also an important feature of a comprehensive simulation framework. This suggests that an understanding of how component performance is affected by the various conditions is prerequisite knowledge, which can be gained through experimentation and subsequently incorporated into the fiber and component models [3,4,[46][47][48][49][50][51].…”

“…Of particular interest is an efficient model that represents connectors between optical fibers, which is essential for modeling a POF-based system. Our connector model follows an approach that is similar to the one used for the SI-POF Injection model discussed above and is based on work presented in [30,50,51]. The key assumption of the model is that for a particular connector, the output intensity at some angle θ i is a weighted linear summation of the input powers at all input angles.…”

“…As the radiated intensity has circular symmetry, the explicit dependency on ϕ has been omitted. It is also possible to model lateral and longitudinal misalignments between fibers via analytical expressions [50,51]. This method is based on the hypothesis that each point in the fiber end surface acts as an independent uncorrelated source whose radiation pattern is given by g(θ), as shown in Figure 3a.…”

“…Once the radiated intensity has been obtained, misalignment loss is calculated assuming that the intensity captured by the receiving fiber is the fraction of intensity radiated from the first fiber that overlaps with the core surface of the second fiber, as shown in Figure 4. In this case, the model produces a scalar power-loss factor l p (r 0 , z 0 ) for a given pair of misalignments [51]. A more flexible approach is to calculate the proportion of light that on exiting the radiating fiber at a given angle of interest in free-space (thus, an external angle) θ i,ext , is able to reach the receiving fiber.…”

“…Then, instead of a circular pattern, its projection onto a perpendicular plane will be a very narrow ring. The equations to calculate this angular loss function are: In this case, the model produces a scalar power-loss factor lp(r0, z0) for a given pair of misalignments [51]. A more flexible approach is to calculate the proportion of light that on exiting the radiating fiber at a given angle of interest in free-space (thus, an external angle) θi,ext, is able to reach the receiving fiber.…”