Consider a SCM system having 80 channels each modulated at 3.5% The link consists of 12 km of single mode fiber having a n attenuation of 1 dB /km plus 4 connectors having a loss of 0.5 dB each. A laser source used in the link couples 2 mW of optical power into the fiber and has a RIN noise of -135 dB/Hz. An In Ga As avalanche photodiode having M=10 and F(M) = M^0.7is used in the receiver , having a responsivity of 0.6A/W, Effective bandwidth of 5 GHz Dark current ID= 10 n A , R_eq= 100 ohms and Ft= 3 dB , Assume room temperature is 25C. Find the carrier to noise ratio