1. OSNR: In a Radio over Fiber link, RF input power to the laser is +27 dBm. Laser

input impedance is 50 ohm and laser modulation gain Gm is 0.1 mW/mA.

(a) There are two connectors between the laser and photodiode, each with 1 dB loss

and three splices each with 0.5 dB loss. Fiber attenuation is 0.5 dB/km. Receiver

output impedance is also 50 ohm. Detector responsivity 0.8 and avalanche gain

M is 50. Find the optical link loss Lop as a function of fiber length L km.

(b) What is the RF power emanating from the photo detector (before the avalanche

gain)?

(c) Find the mean square value of the ac component of the detector current id.

(d) If the total optical link noise is 1 x 10-12 A² over the given bandwidth, find the

OSNR for L 5, 10 and 20 km considering the avalanche gain.

(e) Plot OSNR vs L.