The chaotic unpredictability of vertical-cavity surface-emitting lasers (VCSELs) with polarization-rotated optical feedback is evaluated quantitatively via the normalized permutation entropy H. The effect of polarization mode competition (PMC) is explored. For weak PMC, the H for X-polarization mode, Y-polarization mode, and total output are close to each other, while for strong PMC, the H for the total output is the highest one, which indicates that the permutation entropy is an effective tool for quantifying chaotic unpredictability of VCSELs and provides valuable information for choosing the proper chaotic carrier.
© 2011 Optical Society of America
Original Manuscript: September 3, 2010
Revised Manuscript: December 10, 2010
Manuscript Accepted: December 10, 2010
Published: January 21, 2011
Shuiying Xiang, Wei Pan, Lianshan Yan, Bin Luo, Xihua Zou, Ning Jiang, and Kunhua Wen, "Influence of polarization mode competition on chaotic unpredictability of vertical-cavity surface-emitting lasers with polarization-rotated optical feedback," Opt. Lett. 36, 310-312 (2011)