We propose a scheme for multilevel (nine or more) amplitude regeneration based on a nonlinear optical loop mirror (NOLM) and demonstrate through numerical modeling its efficiency and cascadability on circular 16-, 64-, and 256-symbol constellations. We show that the amplitude noise is efficiently suppressed. The design is flexible and enables variation of the number of levels and their positioning. The scheme is compatible with phase regenerators. Also, compared to the traditional single-NOLM configuration scheme, new features, such as reduced and sign-varied power-dependent phase shift, are available. The model is simple to implement, as it requires only two couplers in addition to the traditional NOLM, and offers a vast range of optimization parameters.
© 2014 Optical Society of America
Original Manuscript: February 12, 2014
Manuscript Accepted: March 8, 2014
Published: April 15, 2014
Mariia Sorokina, "Design of multilevel amplitude regenerative system," Opt. Lett. 39, 2499-2502 (2014)