The effect of amplitude and delay errors on the S21 of a multi-channel broadband microwave photonic link

In order to avoid an unacceptable in-band S21 flatness in the multi-channel broadband microwave photonic system design, this paper established a relationship between the S21 flatness of a muti-channel broadband link and amplitude and delay errors. According to the deduction, the effect of amplitude error on S21 flatness is much less than that of delay error. And the maximum in-band S21 difference is expressed into a function of the muti-channel delay inconsistency. According to the derivation, for ensuring the in-band S21 flatness of a multi-channel microwave photonic system is less than 3dB, the delay error must be less than 13.89ps. Experimental results and simulation results demonstrate the reliability of the derivation relationship between the in-band S21 flatness and amplitude and delay errors.