1/f frequency noise effects on selfheterodyne linewidth measurements
Abstract
The effects of 1/f frequency noise on selfheterodyne detection are described and the results are applied to the problem of laserdiodelinewidth measurement. Laser diode linewidths determined by selfheterodyne methods are not adequate predictors of coherent communications system performance because the measurements often include significant broadening due to 1/f frequency noise. In this report, the autocorrelation function and power spectrum of thedetected selfheterodyne photocurrent are developed in terms of an arbitrary frequency noise. From numerical analysis, the power spectrum resulting from the 1/f frequency noise is shown to be approximately Gaussian and an empirical expression is given for its linewidth. These results are applied to the problem of selfheterodyne linewidth measurements for coherent optical communications, and the amount of broadening due to 1/f frequency noise is predicted. Two methods are then provided for estimating the portion of the measured selfheterodyne linewidth due to the white component of the frequency noise and the portion due to 1/f frequency noise.
 Publication:

Journal of Lightwave Technology
 Pub Date:
 April 1991
 DOI:
 10.1109/50.76663
 Bibcode:
 1991JLwT....9..485M
 Keywords:

 Diodes;
 Frequencies;
 Lasers;
 Noise Measurement;
 Noise Prediction;
 Optical Communication;
 Power Spectra;
 Heterodyning;
 Numerical Analysis;
 Lasers and Masers