1,722,625 research outputs found
Design of geometric phase holograms with arbitrary polarization states and waveforms
No full textWe furnish a general procedure for the geometric phase hologram (GPH) design, starting from the desired output phase profile and polarization states, and extending the theory of polarization gratings (PG) to arbitrary phase profiles. As an example, we consider the case of liquid crystal (LC) devices
Design and performances of logarithmic wavelength demultiplexers
No full textWe investigate the performance and furnish design guideline for a 1×N router realized as a tree of Mach-Zehnder interferometers, with free-spectral ranges that follow a logarithmic progression. We show that the crosstalk can be reduced and the channel passband flattened by inserting all-pass (AP) filters in the interferometers arms, with a suitable choice of the coupling ratios. The proposed device is inherently low loss and the chromatic dispersion introduced by the AP filters can be easily compensated. Two different realizations are investigated, and the power penalties induced by losses and dispersion are evaluated numerically
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