High Linearity Microwave Photonic Up-Conversion System Based on Parallel Dual-Drive Mach-Zehnder Modulators  
[PERSON]  
1 School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China; [EMAIL_ADDRESS] (W.W.); [EMAIL_ADDRESS] (Y.B. ); [EMAIL_ADDRESS] (S.F. ); [EMAIL_ADDRESS] (X.S. ); [EMAIL_ADDRESS] (Y.G. ); [EMAIL_ADDRESS] (M.Z.) [PERSON]  
1 School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China; [EMAIL_ADDRESS] (W.W.); [EMAIL_ADDRESS] (Y.B. ); [EMAIL_ADDRESS] (S.F. ); [EMAIL_ADDRESS] (X.S. ); [EMAIL_ADDRESS] (Y.G. ); [EMAIL_ADDRESS] (M.Z.) [PERSON]  
1 School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China; [EMAIL_ADDRESS] (W.W.); [EMAIL_ADDRESS] (Y.B. ); [EMAIL_ADDRESS] (S.F. ); [EMAIL_ADDRESS] (X.S. ); [EMAIL_ADDRESS] (Y.G. ); [EMAIL_ADDRESS] (M.Z.) [PERSON]  
1 School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China; [EMAIL_ADDRESS] (W.W.); [EMAIL_ADDRESS] (Y.B. ); [EMAIL_ADDRESS] (S.F. ); [EMAIL_ADDRESS] (X.S. ); [EMAIL_ADDRESS] (Y.G. ); [EMAIL_ADDRESS] (M.Z.) [PERSON]  
1 High Linearity Microwave Photonic Up-Conversion System Based on Parallel Dual-Drive Mach-Zehnder Modulators. _Studieria_**2022**, 9, 236. [[https://doi.org/10.3309/ch0](https://doi.org/10.3309/ch0)]([https://doi.org/10.3309/ch0](https://doi.org/10.3309/ch0))  
compensation is only suitable for a down-conversion system with a lower output signal frequency. The method of optimizing the structure of the microwave photonic frequency conversion system in the analog domain is much more universal, such as using low relative intensity noise lasers [16] and low noise optical amplifiers [17]. However, these measures only decrease the noise power of the system and cannot suppress the third-order intermodulation distortion (IMD3) components generated during the frequency conversion process. The schemes to suppress IMD3 components were widely investigated. In [18], by properly setting the three DC bias voltages of a dual-parallel Mach-Zehnder modulator (DP-MZM), the SFDR enhancement of the frequency conversion link can be achieved. However, the modulation of the local oscillator signal requires cascading an additional intensity modulator. In addition, the three DC biases must be precisely controlled at specific voltages, which increases the complexity of the system and the difficulty for real applications. A phase modulator often has higher linearity than an intensity modulator and does not require bias control. By adjusting the polarization state of the light between the two cascaded phase modulators and the response of the back-end optical filter, the enhancement of SFDR can be achieved [19]. However, it is hard for optical filters to filter out low-frequency signal sidebands near the carrier, which makes it difficult to be utilized for frequency up-conversion. The polarization state adjustment of light in polarization multiplexed links can also improve the SFDR of the system [20]. By adjusting the modulation index of the LO signal in the phase modulation link to a certain value, the IMD3 components can be suppressed [21]. However, the increase in modulation depth brings much attenuation of fundamental signal power. In this paper, we propose a large dynamic frequency up-conversion scheme, which utilizes two dual-drive Mach-Zehnder modulators (DD-MZMs) and a balanced photodetector (BPD) to form two parallel microwave photonic links. The intermediate frequency (IF) signal and the local oscillator (LO) signal are, respectively, loaded into the two RF input ports of the DD-MZM in the two microwave photonic links, and the DD-MZM works at the carrier-suppressed double-sideband (CS-DSB) modulation state. By optimizing the distribution ratio of the optical carrier power and the IF signal power between the two microwave photonic links, the IMD3 components are cancelled upon the BPD.