Theoretical Proposal of an Optical Detection System Using DFB Laser with a Very Small Aperture

Minoru YAMADA  Daisuke KAWASAKI  Hirofumi AWABAYASHI  Moustafa AHMED  

IEICE TRANSACTIONS on Electronics   Vol.E85-C   No.3   pp.831-838
Publication Date: 2002/03/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Lasers, Quantum Electronics
DFB laser,  near field optics,  very small aperture,  optical pick-up,  optical head,  

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An optical detection system using a DFB laser with a very small aperture is theoretically proposed. The threshold gain level in DFB laser is sensitively varied with combined reflections by the facet and the corrugation as well as with the optical injection reflected at the surface of the optical disk. Variation of the threshold gain level is counted as the voltage change on electrodes of the laser. It is found that sensitivity of the optical detection with a well-designed DFB laser becomes six times larger than that with conventional Fabry-Perot ones. Field distribution around the small aperture is analyzed taking into account both the near-field and the radiation field. Numerical data on the voltage change are given as examples of the detection system.