| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 89 === Polarization mode dispersion causes an increasing interest in the last few years because of it is a major limitation to the transmission capabilities of high bit rate digital optical transmission system. PMD is generated when a lightwave opagates
through a birefringence medium, such as noncollinear TeO2 AOTF. A vertical polarized light incident into the anisotropic
medium which is perturbed by a shear sound wave generates an
orthogonal polarized light at the output region. During the AO
interaction, both the ordinary and extraordinary diffracted light in an anisotropic medium can be described by the Maxwell's
equations. Under the kDB coordinate systems, a set of vectorial
coupled wave equations that can be described between the ordinary and extraordinary light can be derived. Due to the AO
interaction, the light with one polarized can be coupled into
another polarized light, hence cause polarization change. A PMD
is therefore induced.
The polarization of a monochromatic light can be described by three unit stokes vectors, s1, s2, s3, and from the defining relation between stokes vectors and polarization dispersion vector, the differential group delay can be derived. The mean differential group delay of the AOTF device can be determined by counting the number of extreme per unit wavelength internal in the transmission spectrum as a wavelength-dependent state of polarization. An experiment is set up to check the validity of our theoretics. The theoretical and experimental results can be computed. Certain identical patterns are observed.
|
|---|
