Microwave photonic filters with programmable bipolar coefficients based on π-phase inversion of DSB sidebands

A new technique to realise dynamic negative coefficients for microwave photonic signal processors is presented. It is based on π-phase inversion of two sidebands in double-sideband (DSB) modulation, through spectral-line phase manipulation. The all-optical technique has advantages of enabling scaling to multiple-taps, and is highly versatile because it is programmable and enables dynamic reconfiguration of all the taps using only software. Experimental results demonstrate a programmable bipolar photonic signal processor with operation to high frequencies.