3] For some semiconductor lasers the semiconductor the wafer itself forms the resonant cavity. Let's suppose we have an active medium embedded in a silicon wafer (refractive index n = 3.48} and thickness L = 500 um. Assume the wavelength of the laser emission is 1.20 urn. a} What is the reflection coefficient at the silicon wafer interfaces, r? b] What phase 5 does the electric field acquire for one pass inside the silicon? c] Derive the formula of the Fahrv-Perot transmission for this cavity, in terms of n, PL, r, and L, and the field transmission coefficient, t. d] What is the coefficient of finesse F for the cavity? e) What is the freq uencv spacing for the fringes? f} What is the Finesse of the cavity