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szuyul / MMF-simulation

Compute the vectorial model of guided modes in an optical multimode fiber (MMF) and simulate fiber transmission in different representations.
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Wrong in line79-80 of MMF_simTM_LP.m #4

Open MrDongZhenyu opened 4 years ago

MrDongZhenyu commented 4 years ago

Hello, I guess something gets wrong with line79-80 in MMF_simTM_LP.m, I think it can not agree with the dispersion relation of LP modes.

szuyul commented 4 years ago

Hi, thanks for reporting. Can you be more specific, like what do you expect to see and what's actually showing? It could help me to figure out the issue.

MrDongZhenyu commented 4 years ago

I think this may help. But may discuss when l=0/1. LP_transcend_func = @(x) ha(x).( besselj(l-1,ha(x))./besselj(l,ha(x)) )+qa(x).( besselk(l-1,qa(x))./besselk(l,qa(x)) ); The dispersion relation of LP mode is (in Latex)

\frac{Jl(u)}{u*J{l-1}u} = -\frac{Kl(v)}{v*K{l-1}v} (l>=2)

szuyul commented 4 years ago

I think for LP modes based on weakly guidance condition, the twofold solutions degenerate from exact solutions and have the same propagation constants. It may make sense for exact solution to have conditional equations for l = 0 and l >= 0, but due to the LP mode assumption, I thought the current equation is general for all l number?