Fiber
µm
–
nm
Input beam
µm
–
Misalignments
µm
mrad
µm
Results
Multimode & lens solver advanced
mm
What this means
η vs lateral offset
η vs tilt
η vs axial defocus
Alignment tolerance budget
Model: η = η_axial · exp[−2d²/(w₁²+w₂²)] · exp[−2(πθ/λ)²·w₁²w₂²/(w₁²+w₂²)], with
η_axial = 4/[(w₁/w₂+w₂/w₁)² + (λz/πw₁w₂)²] — the Gaussian overlap integral result. M²>1 beams are treated by
scaling the embedded-Gaussian divergence; for multimode fibers (V>2.405) the result applies to the LP₀₁
fundamental mode only. Tolerances assume each error acting alone.