CMOS-compatible tunable microwave photonic band-stop filter

A method of processing electrical signals, comprising:

• modulating an optical signal having an optical carrier frequency to generate a modulated optical signal, said modulation being based on an electrical input signal;
• filtering said modulated optical signal in an optical filter having first and second spectral attenuation bands to produce a filtered optical signal, wherein the optical carrier frequency is substantially centered between said first and second spectral attenuation bands;
• and
• converting the filtered optical signal into an electrical output signal, wherein the optical filter comprises:
• a Mach-Zehnder interferometer having first and second internal interferometer arms, both coupled between two optical couplers;
• and
• first, second, third, and fourth optical resonators, each coupled to the first interferometer arm.

A device, comprising:

• an optical modulator adapted to modulate an optical signal having an optical carrier frequency to generate a modulated optical signal, said modulation being based on an electrical input signal;
• an optical filter having first and second spectral attenuation bands and adapted to filter said modulated optical signal to produce a filtered optical signal, wherein the optical carrier frequency is substantially centered between said first and second spectral attenuation bands;
• and
• an optical-to-electrical (O/E) converter adapted to convert the filtered optical signal into an electrical output signal, wherein the optical filter comprises:
• a Mach-Zehnder interferometer having first and second internal interferometer arms, both coupled between two optical couplers;
• first and second optical resonators, each coupled to the first interferometer arm, wherein:
• optical losses induced by the first optical resonator result in the first spectral attenuation band;
• and
• optical losses induced by the second optical resonator result in the second spectral attenuation band;
• and
• third and fourth optical resonators, each coupled to a corresponding one of the first and second interferometer arms via a corresponding tunable optical coupler, wherein:
• the optical filter further has third and fourth spectral attenuation bands;
• optical losses induced by the third optical resonator result in the third spectral attenuation band;
• optical losses induced by the fourth optical resonator result in the fourth spectral attenuation band;
• and
• both the third optical resonator and the fourth optical resonator are coupled to the first interferometer arm.