In the paper, an OADM based on fiber gratings and circulators is demonstrated. In order to reduce the interferometric crosstalk severely degrading the system performance in the common structure, a novel structure of cascaded gratings is proposed, which can reduce the power penalty induced by the interferometric crosstalk to the level of noninterferometric crosstalk without the need of raising the peak reflectivity of the fiber gratings. Optical spectra of the related ports in the two structures are measured, which show a 3dB reduction of the crosstalk induced by the dropped signal and complete suppression of the crosstalk induced by the added signal in the novel structure. The temperature compensation technique is used, which can reduce the temperature sensitivity of the fiber gratings to 0.11nm/100 degrees C in the range of working ambient temperature. With the fiber gratings annealed for 4 hours in 120 degree C, the long-term stability of the device is greatly improved.
展开▼
