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PhD. of Frederik W.J. Fransoo

Author: Frederik Fransoo
Promotor: Roel Baets
Dutch Title: Performantie-analyse van een uitleessysteem voor optische schijven gebaseerd op een multimodale golfgeleider
English Title: Performance analysis of a multi-mode waveguide based optical disc readout system
Date: 14/4/2005
Main Language: English with Dutch Summary
Thesis: Download the PhD Thesis (5.1MB) (5.1MB)
Presentation: Download the Presentation (3.2MB) (3.2MB)


In this thesis a new technique to read out optical discs has been investigated. The idea is to enhance the resolution by using two different waveguide modes to detect reflected light from the disc, generating two electrical signals. These two signals detect together the amplitude and the derivative of the phase of the reflected field. A theoretical comparison of the waveguide detection method with the conventional DVD read-out mechanism and the confocal microscope shows that each system is limited with the same diffraction limit. The actual resolution is however also influenced by the noise. The effect of inter symbol interference, inter track crosstalk and noise have been modeled in a two-dimensional model and shows that the fraction of bit errors can be decreased by combining the signals of the two modes. This opens the way for a reduction in bit size. A photonic integrated circuit to control the interface of the waveguide modes with the laser source and the detector, was designed and fabricated. The measurements on the isolated chip gave good results. Experimental evidence for the resolution enhancement could however not be produced primarily due to the low power output of the first order mode.

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