1. The problem statement, all variables and given/known data One of the most exciting developments in lightwave engineering is the Erbidium doped fiber amplifier (ERDF A). It is very quiet(low noise) has a bandwidth of hundreds of GHz and relatively low cost.The fiber is "pumped" by a semiconductor laser operating at 850nm and the light carrying the information at 1550nm is amplified. The 'attenuation' constant is given as u=-0.046m^-1. If I have 0.01mW entering the ERDFA and I would like to get 100mW out, how long should be my fiber amplifier? If the efficiency of the amplifier is 20% how much pumping power do I need? 2. Relevant equations Loss Equation e^(-2*α(z1-z0) alpha is attenuation constant if the negative sign was removed. would this be a gain equation? 3. The attempt at a solution I do not know where to start, the teacher said the wavelengths were irreverent.