Conducting a wide-range single-transverse mode operation in a commercial multi-mode VCSEL by beam-profile transferred optical feedback

In this research, a beam-profile transferred optical feedback (BTOF) method was employed to conduct a wide range single-transverse mode operation of a commercial multi-mode VCSEL. In BTOF, a spatial modulation optical system was used to reconfigure the spatial distribution of the feedback beam, and to control the laser's transverse mode. Experimental results indicated that, over a range of about 8.7 times of the laser's threshold current, BTOF could conduct the laser to output a single-transverse mode with high spectra purity and low intensity noise. While, without optical feedback, the solitary laser exhibited a multi-mode output with a complicate variation in mode distribution as the laser's current was tuned. More special features of BTOF will be presented in the report.