Pulse reflection of tunable Fiber Bragg Grating WDM filter

To determine the rate performance of tunable WDM filter at high bit rates, the pulse response of the filter based on Fiber Bragg Grating (FBG) is studied. We qualitatively explain the interaction of the input pulse when it propagates through the grating. For the three examined cases: 10 Gbit/s, 20 Gbit/s, 40 Gbit/s, the reflected pulses have the same input shape, but in the two latter cases, a wide Full Width at Half Maximum (FWHM) is noted what generating chromatic dispersion. Material dispersion is found to play only a minor role in the pulse response versus different rates. In a second part, under the appropriate bit rate, the pulse response of the WDM filter is investigated when it is tuned by temperature effect. The filter response will be tuned only in UDWDM and DWDM domain because of the high temperature value required in WDM. The main feature is the very weak amplitude of the reflected pulse from tuned FBG which provides negligible interference in high rate communication systems.