Multiple passband microwave photonic filter with adjustable bandwidth

Abstract

We propose a straightforward technique that allows adjusting the bandwidth of microwave filtered signals by using two tunable optical bandpass filters. The principle of operation of the microwave photonic filter that allows the generation of passband windows is described by a full mathematical analysis. The electrical bandwidth of each generated passband window is adjusted by optically filtering a multimode laser diode. We demonstrate that the proposed filter can generate passband windows located at 4.87 GHz and 9.63 GHz exhibiting a bandwidth of 284.54 MHz and 391.24 MHz, respectively. The electrical bandwidth of each passband window can be increased to a maximum value of 1000 MHz by means of an adequate adjustment of the optical bandwidth from 2 nm to 10 nm approximately. A potential application of this proposal resides in the fact that the microwave filtered signals can be used as electrical carriers in optical communication schemes taking advantage of the electrical bandwidth that can be tailored according to a data transmission.