Analysis of temperature effect in fiber optics ring resonator based on photonic crystal fiber

In-fiber Mach-Zehnder interferometer for gas refractive index measurements based on a hollow-core photonic crystal fiber

“…The value α L is the cross-section-weighted average of the linear thermal expansion coefficients of the hollow-core fiber material, α silica = 5.5 × 10 −7 K −1 [10,11] and its 50 μm acrylate coating, approximated with α PMMA = 7.6 × 10 −5 K −1 [11,12]. With Δn eff = 0.0096 (see section 5) we determine ∂L/∂T (n 1 eff -n 2 eff ) = 2.0 × 10 −7 m K −1 .…”

“…In optical resonators the linewidth, δλ, of a cavity resonance is used and in interferometers it would be most practical to use the width of an interference fringe, δφ = π/2 which results with Eq. (3) in δλ = Δ (10) and the figure of merit is therefore simply…”