PROPAGATION LENGTH OF GUIDED-WAVES IN LOSSY SI FILM SANDWICHED BY IDENTICAL DIELECTRICS

We have measured a propagation length L of TM(0) and TE(0) guided wave s in a lossy Si film surrounded by identical dielectrics 632.8 nm in w avelength. The propagation length L(ATR)((E)) estimated from experimen tal attenuated total reflection (ATR) spectra deviated largely from th e propagation length L(ATR)((T)) estimated from calculated ATR spectra in the range of small optical thickness of Si film h(opt). This discr epancy may arise from an angular beam spread of incident light. We hav e proposed a method to measure L directly. This method gave us an L fo r TM(0) guided waves of 1.6 mm at h(opt) = 6.1 nm. This value is in go od agreement with L(ATR)((T)) when L(ATR)((E)) = 0.2 mm, under certain conditions.