Linearity improvement of analog photonic link based on a phase-coherent orthogonal light wave generator

This Letter presents a novel, to the best of our knowledge, linearized analog photonic link (APL) based on a phase-coherent orthogonal light wave generator that consists of a polarization-dependent Mach-Zehnder modulator (MZM) and a polarization controller (PC). By adjusting the PC and bias voltage of MZM, the third-order intermodulation (IMD3) terms can be suppressed while retaining a high gain for the fundamental terms, which indicates that the spurious free dynamic range (SFDR) of the proposed APL can be much improved. To further verify the feasibility of the proposed APL, a proof-of-concept experiment is performed, and the performances are compared with conventional APL. The experimental results demonstrate that a 14 dB improvement in the fundamental to IMD3 power ratio and an SFDR of 100.2dB⋅Hz^2/3 or 119.1dB⋅Hz^2/3 for a noise floor of -139dBm/Hz or -163.9dBm/Hz are achieved. In addition, an orthogonal frequency division multiplexing signal with 30 MHz bandwidth centered at 2.5 GHz is delivered by our proposed APL, whose signal-to-noise ratio is increased by 10 dB, compared to conventional APL.