High wavelength dependent bandwidth performance of doubly clad microstructured GI POF

In this study, we use an approach based on the power flow equation (PFE) to investigate how the bandwidth, equilibrium mode distribution (EMD) and steady-state distribution (SSD) of a designed doubly clad W-type microstructured plastic optical fiber (mPOF) with a graded-index (GI) core distribution evolves with wavelength. Our analysis shows that the bandwidth decreases as fiber length increases at all wavelengths studied, while it increases with the wavelength. This behavior is linked to a reduction in mode delay time per unit length, leading to decreased modal dispersion. On the other hand, widening the inner cladding of the W-type GI mPOF causes a decrease in bandwidth due to the rise in the number of guided modes, which increases modal dispersion. When comparing the bandwidth of the W-type GI mPOF, which is 2.7 GHz km at λ = 645 nm, to the measured bandwidth of the conventional GI POF, which is 460 MHz m at λ = 633 nm, the W-type GI mPOF clearly exhibits a substantially higher bandwidth. Another important benefit of mPOFs over traditional POFs lies in their ability to precisely adjust air-hole diameters and pitches with greater flexibility, without the need for complex doping processes as required for standard POFs. These results offer insights for communication and sensory systems that use multimode GI mPOFs across varying wavelengths.