A programmable filter for electronic signals. The filter includes an input that splits power of the input signal along two paths, a first and second path that is phase shifted by ninety degrees in respect of the first path. The first and second path are each modulated to the optical domain, and provided as input to respective filter chains. The in-phase signal can be filtered by IIR or FIR optical filters with configurable operation, as well the shifted signal can be filtered by a second chain of IIR and FIR optical filters with configurable operation. Resulting output from each filter chain is recombined and demodulated from the optical domain. In this manner, the electronic filter can adopt any suitable impulse response, including impulse responses described with complex coefficients. Real parts can be configured by operation of the first filter chain and imaginary parts by operation of the second filter chain.