Bazargani Hamed Pishvai, Fernández-Ruiz María del Rosario, Azaña José
Opt Lett. 2014 Sep 1;39(17):5232-5. doi: 10.1364/OL.39.005232.
We propose and numerically demonstrate a new design concept for implementing nondispersive complementary (band-pass/band-reject) optical filters with a wide range of bandwidth tunability. The device consists of two photonic Hilbert transformers (PHTs) incorporated into a Michelson interferometer (MI). By controlling the central frequency of PHTs with respect to each other, both the central frequency and the spectral width of the rejection/pass bands of the filter are proved to be tunable. Bandwidth tuning from 260 MHz to 60 GHz is numerically demonstrated using two readily feasible fiber Bragg grating-based PHTs. The designed filter offers a high extinction ratio between the pass band and rejection band (>20 dB in the narrow-band filtering case) with a very sharp transition with a slope of 170 dB/GHz from rejection to pass band.
我们提出并通过数值模拟证明了一种用于实现具有广泛带宽可调性的非色散互补（带通/带阻）光学滤波器的新设计概念。该器件由两个集成到迈克尔逊干涉仪（MI）中的光子希尔伯特变换器（PHT）组成。通过相互控制PHT的中心频率，证明了滤波器阻带/通带的中心频率和光谱宽度均可调。使用两个易于实现的基于光纤布拉格光栅的PHT进行了从260 MHz到60 GHz的带宽调谐数值演示。所设计的滤波器在通带和阻带之间提供了高消光比（在窄带滤波情况下>20 dB），从阻带到通带具有非常陡峭的过渡，斜率为170 dB/GHz。
