Dispersion Compensation in Analog Photonic Link Utilizing a Phase Modulator

A simple chromatic dispersion (CD) compensation scheme for a certain frequency is first proposed by utilizing a phase modulator in conjunction with a polarizer. Properly adjusting the input polarization states, the frequency response of the dispersive link can be controlled. Experimental results show that the dispersion-induced power fading (PF) occurred at 14 and 10.8 GHz over 40- and 65-km transmission is fully maximized or compensated. Furthermore, the spurious-free dynamic range of the proposed analog photonic link is improved to 96 dB·Hz^2/3 for the 40-km fiber transmission, which is 12 dB higher than that of the phase modulation-based link. On the other hand, an improved scheme for CD compensation is further demonstrated, where a polarization beam combiner is employed instead of a polarizer. Such an approach achieves the broadband CD compensation since it can be equivalent to the sum of two first schemes. In this case, the PF is greatly mitigated for the RF signal with a bandwidth up to 15 GHz. Meanwhile, the error vector magnitude reduces to ~5% with the fluctuation of only 0.7%.