New Multimode W-Type Graded-Index Silica Photonic Crystal Fiber for High Bandwidth Data Transmission

We present a novel design for a multimode, doubly clad W-type silica photonic crystal fiber (SPCF) featuring a graded-index (GI) core profile, developed to enhance bandwidth performance. The bandwidth potential of this fiber was assessed through comprehensive modeling based on the power flow equation (PFE). Compared to conventional singly clad OM4 and OM5 silica optical fibers (SOFs) with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$50-\mu \mathrm{m}$</tex> GI cores–offering a bandwidth of 4.7 GHz·km–the proposed <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$50-\mu \mathrm{m}$</tex> core W-type GI SPCF achieves a higher bandwidth of 5.6 GHz·km at 850 nm. A fiber design with inner cladding results in leaky mode losses, supports fewer higher-order guided modes, and exhibits reduced modal dispersion. As a result, the proposed W-type GI SPCF is well-suited for high-data-rate fiber optic applications, including data centers, enterprise networks, and telecommunications systems. Moreover, one of the standout advantages of SPCF technology over traditional SOFs lies in its design flexibility: the ability to tailor air-hole diameters and spacing (pitches) offers precise control over optical properties, eliminating the need for the complex doping processes typical of standard SOFs.