Abstract

Reduction of semiconductor laser frequency noise and equalization of its FM transfer function are essential in a variety of fields, including precision optical measurements and coherent optical communication systems. [1-4] A wide variety of methods exist to suppress laser frequency noise such as locking to a stable master laser [1], using optical frequency discrimination and electrical feedback [2], using an external cavity [3], or using a external-cavity and electrical-feedback hybrid [4], We present wide bandwidth frequency noise suppression with simultaneous FM equalization using electrical feedback. To our knowledge, our system is unique in three respects: it actively suppresses frequency noise over 2.5 times more bandwidth than previously reported results [2]; it achieves active equalization of the FM transfer function over approximately 10 times more bandwidth than previously reported results [5]; and we have measured one of the narrowest i.f. linewidths for semiconductor lasers [3].

© 1991 Optical Society of America