An amplitude limiting circuit is utilized to select the most favorable linear region of the light vs. current characteristic curve (for directly modulated lasers) or the lasers modulator transfer function (for externally modulated lasers) by preventing excursions of the broadband, multiplexed...http://www.google.com/patents/US5689356?utm_source=gb-gplus-sharePatent US5689356 - System and method for minimizing nonlinear distortion in optical communication systems employing laser intensity modulation 
