| Summary: | 碩士 === 國立交通大學 === 電子物理學系 === 82 === In this thesis, we study spontaneous emission in slab and
cylindrical dielectric waveguides and the coupling factor in
micro-cavity, including surface emitting lasers, micro -disk
and micro-ring lasers, by numerical simulations. Strong
dependence of spontaneous emission rate on the dipole
orientation was found. In planar waveguides, the emission for
vertical dipoles was essentially inhibited, while the emission
for horizontal dipoles falls into the lowest TE mode when
thickness of the waveguide is a fraction of optical wavelength.
Total spontaneous emission rates are obtained by adding the
contribution from waveguide modes and radiation modes.
Spontaneous emission factor β, defined as the fraction of
total spontaneous emission into the waveguide or laser mode,
was also found to depend strongly on the dimension of the
structures. For proton-implanted GaAs surface emitting lasers
incorporating AlGaAs/AlAs distributed Bragg reflectors, β is
1.85E-3. For micro-ring,β is as large as 0.925. As for micro-
disk lasers,the disk diameter is 1 ∼5μm,when β is 0.1∼0.25 .
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