Measuring gain and noise figure of erbium-doped fiber amplifiers using a broad-band source and a transmission filter

We report a unique low-cost technique for measuring gain and noise figure (NF) in erbium-doped fiber amplifiers using a broad-band amplified spontaneous emission source and a transmission filter, by extracting the slope and intercept of output power spectral density versus input power spectral density at filter edges. The required filter depth is 30 dB. Discrepancies of ≤0.3 dB are found between gain or NF obtained from this technique and those measured using conventional spectral-interpolation technique employing multiple lasers at 100-GHz spacing across the C-band.