Author Affiliations
1Key Laboratory of Science and Technology on Electronic Information Control, Chengdu 610029, China2Center for Information Photonics & Communications, School of Information Science & Technology, Southwest Jiaotong University, Chengdu 610031, China3Science and Technology on Communication Security Laboratory, Institute of Southwestern Communication, Chengdu 610041, Chinashow less
Fig. 1. Simplified diagram of linearized downconversion link and corresponding signal spectra and transfer characteristics. DE-MZM/DD, dual-electrode Mach–Zehnder modulated direct detection; IMD3, third-order intermodulation distortion; IIE, intelligent impairment equalization; RF, radio frequency; IF, intermediate frequency.
Fig. 2. Equalization-based inverse link transfer function estimation. BP, backpropagation.
Fig. 3. Experimental setup of proposed linearized microwave downconversion link. LD, laser diode; PC, polarization controller; DE-MZM, dual-electrode Mach–Zehnder modulator; LO, local oscillator; EDFA, erbium-doped fiber amplifier; PD, photodetector; IIE, intelligent impairment equalization.
Fig. 4. (a) Dependence of MSE on the number of epochs for the training subsets; inset, the electrical spectrum of two-tone signal with the MSE of 10−6; (b) DE-MZM/DD-based transmission link and calculated inverse link transfer functions; black solid curve, theoretical inverse transfer function; red dotted curve, IIE-based inverse link transfer function; inset, whole downconversion link transfer characteristic by applying IIE.
Fig. 5. Electrical spectra of the two-tone input tests before and after applying IIE when the frequencies are set to be (a), (b) 2.11 GHz and 2.13 GHz; (c), (d) 2.10 GHz and 2.14 GHz; and (e), (f) 4.11 GHz and 4.13 GHz, respectively.
Fig. 6. Measured SFDR before (solid line) and after (dashed line) IIE.