Assignment 2: Important Notes: 1) Only assignments answered in assignment form will be accepted. 2) Due date for handing in Assignment2 is Monday 10/12/2012. Handing in the assignment: locker 15, 3rd floor. The German University in Cairo Faculty of Information Engineering & Technology Electronics Department Electronics and Communications 9 Photonics (Elct 901) Fall 2012 th semester Assignment 2 Problem 1: Without optical amplification it is not possible to optically transmit data from London to NewYork, i.e. 7000 km of fiber length with an attenuation of 0.2 dB/km. Therefore Erbium doped fiber amplifiers (EDFA), which can amplify an optical input signal of -15 dBm to +1 dBm, are employed for a transatlantic fiber link. Assume that the optical transmitter at London is sending with an optical power of +1 dBm and that the receiver at New York is able to detect optical signals down to -35 dBm. How many EDFA are necessary for a working optical transatlantic fiber link? Problem 2: Describe briefly the principle of operation of a Raman amplifier. Explain in words at what wavelengths can signals be amplified. Problem 3: Quartz is a positive uniaxial crystal with ne = 1.553 and no = 1.544. (a) Determine the retardation at λ0 = 633 nm when the crystal is oriented such that retardation is maximized. (b) At what thickness does the crystal act as a quarter‐wave retarder?