Department or Program

Physics and Astronomy


The dynamics of a quantum dot laser (QDL) subject to isotropic and polarization-rotated optical feedback has been investigated experimentally. The polarization and frequency structures of the solitary QDL have been studied for a wide range of bias currents. Our results show that the solitary laser is mainly linearly polarized and operates in the multimode regime starting from the threshold current. The dynamics of the QDL, represented by its power spectrum and temporal fluctuation, are studied while varying parameters including bias current, angle of feedback polarization, feedback strength and external cavity length. We found that the onset threshold of dynamics is lower for polarization-rotated feedback than for isotropic feedback. This shows that QDLs are more sensitive to polarization-rotated optical feedback. Strong dynamics are observed at the polarization angles 45o and 135o, and anti-correlation between the dynamics in orthogonal polarizations is revealed. Additionally, we explored the polarization-resolved optical spectra of the QDL. The data reveal variations in the optical spectra due to changing the angle of feedback polarization. The observed variations include different levels of suppressions and enhancements of individual modes induced by the optical feedback. These suppressions and enhancements are greater for polarization-rotated feedback than for isotropic feedback.

Level of Access

Restricted: Embargoed [Open Access After Expiration]

First Advisor

Lin, Hong

Date of Graduation


Degree Name

Bachelor of Science

Number of Pages


Components of Thesis

1 pdf file