Bandwidth Adjustment of a Microwave Filtered Signal by using an Optical Bandpass Filter

A novel technique to increase the bandwidth of a microwave filtered signal situated at 7.17GHz is described. The filtered signal is obtained by means of a microwave photonic filter that employs in an advantageous manner the chromatic dispersion exhibited by optical fibers. In particular, a multimode laser diode associated to single mode-standard fiber is used. The use of an optical bandpass filter is proposed to modify the optical bandwidth of a multimode laser diode. Experimentally it is demonstrated that the optical bandwidth is changed from 6.69nm to a 2.2nm. As consequence, the bandwidth of the microwave filtered signal is varied from 385MHz to 1.19GHz. A Signal-to-Noise-Ratio of 15dB guarantees a good quality of this signal.