1,279 research outputs found
Anderson localization in a partially random Bragg grating and a conserved area theorem
We investigate the gradual emergence of the disorder-related phenomena in
intermediate regimes between a deterministic periodic Bragg grating and a fully
random grating and highlight two critical properties of partially disordered
Bragg gratings. First, the integral of the logarithm of the transmittance over
the reciprocal wavevector space is a conserved quantity. Therefore, adding
disorder merely redistributes the transmittance over the reciprocal space.
Second, for any amount of disorder, the average transmittance decays
exponentially with the number of grating layers in the simple form of
for sufficiently large , where is a constant and
is the number of layers. Conversely, the simple exponential decay form does not
hold for small except for a highly disordered system. Implications of these
findings are demonstrated
On the Beam Profile and Beam Quality of Gain-Guided Index-Antiguided Fibers with Finite Cladding Boundary
The beam quality factor for the fundamental LP01 mode of a step-index
fiber with a finite cladding diameter is calculated in the presence of gain, in
a closed form, as a function of the complex generalized V-number. It is shown
that the conventional infinite cladding diameter approximation cannot be used
for index-antiguided gain-guided fibers, and the rigorous analysis presented in
this paper is required for accurate prediction of the beam quality factor, as
reported in recent experimental measurements
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