Figure 4: Polarization-multiplex-based two-tap MWP filter.
From: Integrable microwave filter based on a photonic crystal delay line
(a) The delay profiles, based on the experimental results obtained for the TE mode, for the TE and TM modes as a function of wavelength, for illustrative purposes of the filter operation. The TE and TM delays that correspond to the set of wavelengths selected for the filter experimental demonstration are indicated by colored dots, respectively, in blue, green and red for wavelengths of 1,544.5, 1,547 and 1,550.8 nm. (b) Experimental setup. A TLS emitting at λ0 is modulated via a Mach–Zehnder modulator (IM) and carries the input electrical signal si(t). A polarization controller is employed to optimize the power launched from the laser into the modulator. A second polarization controller ensures that both TE and TM polarizations are launched into the PhC. A photodetector then provides the output filtered electrical signal so(t). (c) Calculated (solid lines) and measured (squares) results for the filter response as a function of the wavelength. Blue, green and red markers, respectively, stand for 1,531, 1,537 and 1,542 nm optical wavelength.
