Group delay measurement of WDM components using photonic microwave technique

PMD and CD characterization of chirped fiber Bragg gratings employing photonic microwave technique

“…For accurate DGD measurement, the polarization dependence of the auxiliary fibers, PC, and the fiber-optic coupler should be eliminated by using calibration, where a reflector is used instead of the tested grating. Our calibration results show that less than 0.5-ps DGD is obtained, which is within the noise floor (Ϯ1 ps) of the measurement system [3], and can be omitted in the following DGD measurement of the CFBG.…”

“…To ensure f is determined unambiguously, 0 is chosen to be larger than t in our proposed system [3]. It can be seen that at a fixed input wavelength, that is, where cd is fixed, by changing the input polarization of the device under test (DUT), the filter's frequency-spectrum-range (FSR), FSR ϭ 1/͉͉, is shifted accordingly.…”

“…It is known that CD can be obtained by measuring the wavelength-dependent relative group delay via changing the input wavelength and evaluating the FSR of the notch filter [3,6]. However, since PMD provides polarization-dependent delay, the wavelength-dependent relative group delay measurement of optical devices will be inherently uncertain by up to one half of the DGD.…”

“…The total delay of the test path is t ϭ f ϩ e , where e is the time delay induced by other optical components in the test path. The frequency response of the two-tap filter has a periodic transfer function with notch frequencies, given by [3]:…”

“…Our setup is based on the technique we previously proposed in [3]. Here, we extend this technique to PMD characterization by using polarization scanning.…”