A Highly Linearized Photonic Mixer Based on Unsymmetrical Power Dividing for RoF System

In this paper, a highly linearized photonic mixer is proposed and demonstrated for Radio over Fiber (RoF) system. This scheme is based on an Intensity modulator (IM) and a dual parallel Mach--Zehnder modulator (DPMZM) in series. By adjusting the unsymmetrical power dividing rate and optimizing biases of the DPMZM, the third-order intermodulation distortion (IMD3) is suppressed. A proof-of-concept experimental verification is carried out. 10GHz RF signal is down-converted to2GHz. When the power dividing ratio is 0.1, IMD3 suppression of 33 dB is experimentally demonstrated. The spurious-free dynamic range (SFDR) is improved by 21.4 dB and reaches to 116 dB.Hz4/5 as comparing with the conventional photonic mixer.