Analog radio-over-fiber links with a high SFDR for passive distributed antenna system applications using Lagrange multiplier optimization

An analog radio-over-fiber scheme with a high spurious-free dynamic range (SFDR) is proposed for constructing a passive distributed antenna system (DAS). By developing a Lagrange multiplier constrained optimization model, the best trade-off among RF output power, the polarization incident angle, and the RF power ratio is obtained. Consequently, the third-order intermodulation distortion and second-order harmonic distortion can be suppressed simultaneously simply by varying the polarization incident angle. The simulated and experimental results show that the proposed scheme is effective and feasible. Additionally, this Letter offers valuable insights into the nonlinear optimization, and it may be of great significance in future design and manufacture.