Precision Metrology for Fiber-Amplifier Noise Figure Traceable to a RIN Standard
Gregory E. Obarski, Paul D. Hale
We developed high-precision metrology for fiber-amplifier noise figure based on application of a relative intensity noise (RIN) standard to the RIN subtraction method. Calibration of a RIN/noise figure measurement system using the standard yields a typical standard uncertainty of <0.25 dB for frequency-resolved noise figure measurements (in the range 0.1-1.1 GHz). The RIN calibration source can either be a DFB laser having practically Poisson-limited RIN, or a thermal light source, such as amplified-spontaneous emission from an erbium-doped fiber amplifier (EDFA) that is narrow-pass-band filtered (uncertainty <= 0.1 dB/Hz). Thus, an EDFA whose noise figure is to be determined can be used to perform the RIN calibration (as long as it is devoid of multiple path interference). Results obtained from a second electrical method (reported accuracy +/- 0.3 dB) agree to within +/- 0.2 dB.