Photonic-assisted division calculation of microwave signal envelopes and its applications

An approach to performing photonic-assisted division calculation of two microwave signal envelopes is proposed and experimentally demonstrated. The division calculation involves two operations: reciprocal operation and multiplication operation. The proposed division operation is experimentally evaluated, in which the calculation of three division operations between two sine waveforms, between two sawtooth waveforms, and between a sine waveform and a triangular waveform is experimentally verified. The experimental results exhibit good flexibility and simplicity of the division operation. In addition, the application potential of the divider in generating some microwave waveforms and flat optical frequency comb (OFC) is explored. In the first case, the division operation is used to transform a sine waveform into a sawtooth (or reversed-sawtooth) waveform and a parabolic waveform. In the second case, the division operation optimizes the flatness of an OFC emitted by a mode-locked laser (MLL). An OFC with 0.98 dB flatness among 18 lines and a line spacing of 10 GHz is experimentally obtained. The proposed division operation provides new access to implement microwave waveform generation, transformation, signal processing, and computing.