# Fiber splice loss calculator

Input

μm

°

Output

μm

μm

%

dB

$Loss(dB) = -10\log\left[\dfrac{4 w_1^2 w_2^2}{(w_1^2 + w_2^2)^2}\exp\left(-\dfrac{4\delta^2 + k_0^2 n ^2 w_1^2 w_2^2 \sin^2 \theta}{2(w_1^2 + w_2^2)} \right)\right]$
where $w_1$ and $w_2$ are the mode field radii in fibers 1 and 2, respectively. $\delta$ is the lateral offset between the fibers' cores, $\theta$ is the angular offset between the cores, $k_0=\dfrac{2\pi}{\lambda}$ is the vacuum wave number and $n$ is the refractive index of the fibers' cores.