Multi-Objective Optimization-Based Composite Transimpedance Amplifier Design for NMOR Atomic Magnetometers

In the all-optical nonlinear magneto-optical rotation (NMOR) atomic magnetometer system, the transimpedance amplifier (TIA) is a key front-end stage whose bandwidth, noise, and stability set the limits of the noise floor and overall performance. However, conventional design methods lack unified system modeling and multi-objective constrained optimization, making it difficult to achieve a balanced performance. To address this challenge, this work develops a composite TIA modeling and design methodology that integrates system-level modeling with multi-objective constrained optimization. First, an equivalent circuit model of the photodiode-amplifier system is established, from which the transfer function, noise model, and noise transfer function are rigorously derived, providing a unified basis for gain and noise analysis. Second, the TIA parameter configuration is formulated as a nonlinear multi-objective optimization problem considering phase margin, closed-loop bandwidth, and output noise, which is solved to obtain optimal feedback resistance-capacitance values. Finally, simulation and experiments show that the optimized TIA achieves wide bandwidth, high stability, and ultra-low noise, ensuring the performance requirements of the NMOR atomic magnetometer system.