title: Shifted dispersion-induced radio-frequency fading in microwave photonic filters using a dual-input Mach-Zehnder electro-optic modulator.
abstract: A simple microwave photonic processor structure with single passband response, and widely tunable capability, is demonstrated. It is based on the principle of shifted dispersion-induced radio-frequency (RF) fading by using a dual-input Mach-Zehnder electro-optic modulator (EOM) that is fed from a broadband optical source with unbalanced input fiber lengths into the upper and lower arms of the EOM, in combination with a dispersive medium. This topology consequently produces a spectral response equivalent to the curve of the dispersion-induced RF fading that is shifted from the conventional baseband location to high frequencies. Therefore, an equivalent single passband is formed without the requirement of the conventional tap coefficients. Experimental results verify the structure and demonstrate a continuously tunable microwave filter exhibiting shape invariance and a single passband. In addition, the filter response sidelobe suppression is also significantly improved by applying a Gaussian windowed profile to the broadband optical source.
authors.affiliation: School of Electrical and Information Engineering, Institute of Photonics and Optical Science, The University of Sydney, NSW, Australia. liwei.li@sydney.edu.au
authors.forename: Liwei
authors.initials: L
authors.lastname: Li
authors.forename: Xiaoke
authors.initials: X
authors.lastname: Yi
authors.forename: Thomas X H
authors.initials: TX
authors.lastname: Huang
authors.forename: Robert A
authors.initials: RA
authors.lastname: Minasian