Photon cavity lifetime and total attenuation Consider a semiconductor Febry-Perot (FP) optical cavity that has a length L, end mirrors with reflectances R1 and R2, and attenuation inside the cavity given by s. The total attenuation coefficient for the optical cavity is denoted by t. Calculate the photon cavity time for an In0.60Ga0.40As0.85P0.15 FP optical cavity that has a refractive index of 3.7, length of 300 m and s= 20 cm-2