Analyzing Guided-Modes for Novel and High Performance FBG-OADM Using Improved FEM

Designing a Novel High-Performance FBG-OADM Based on Finite Element and Eigenmode Expansion Methods

“…Specifically, OADMs employ wavelength division multiplexing techniques in the frequency domain to emulate the time division multiplexing capabilities of the traditional synchronous digital hierarchy standard in the time domain. In the past several decades, numerous types of OADM have been proposed, many of which are widely used in various fiber-optic communication systems [7][8][9][10][11][12]. Of all of the currently available OADMs, the most common one is composed of an FBG and two optical circulators.…”

“…In contrast to traditional OADMs, the proposed FBG-OADM is advantageous because it is a miniature-sized all-optical fiber-based multiplexer that can be fabricated through a low-cost and simple manufacturing process [12]. In researching and designing the proposed FBG-OADM, this study combined the finite element method (FEM) and eigenmode expansion method (EEM) to perform numerical simulations for calculation and analysis.…”

“…All subsequently employed mesh-cutting resolutions must, therefore, generate modes with an orthogonal value of less than −40 dB. For mesh-cutting resolutions that failed to meet this standard, the resolution was increased; subsequently the solutions to the modes were recalculated and the orthogonal values were reevaluated [12]. Section 4 introduces the roles and functions of EEM in the numerical simulations and expounds why the combined FEM-EEM approach is superior to traditional numerical simulation methods for designing and analyzing large optical components containing periodic structures.…”

“…Moreover, the proposed FBG-OADM possesses nearly zero heterodyne and homodyne crosstalk and meets the full width at half maximum (FWHM) requirement for dense wavelength-division multiplexers (DWDMs) according to the International Telecommunication Union (ITU; FWHM < 0.4 nm). Figure 1 shows the geometric structure of the proposed FBG-OADM [12]. The structure comprises two SMFs placed side by side (Fibers 1 and 2), a 1 µm thick PML (purple lines), a PRB (yellow lines), a noncoupling area (L 1 and L 3 ); a mode-power coupling area (L 2 ); an HE 11 core mode (red lines); and a cladding mode (black lines).…”

“…The structure comprises two SMFs placed side by side (Fibers 1 and 2), a 1 µm thick PML (purple lines), a PRB (yellow lines), a noncoupling area (L 1 and L 3 ); a mode-power coupling area (L 2 ); an HE 11 core mode (red lines); and a cladding mode (black lines). Figure 1 shows the geometric structure of the proposed FBG-OADM [12]. The structure comprises two SMFs placed side by side (Fibers 1 and 2), a 1 μm thick PML (purple lines), a PRB (yellow lines), a noncoupling area (L 1 and L 3 ); a mode-power coupling area (L 2 ); an HE11 core mode (red lines); and a cladding mode (black lines).…”