Robustness of optic-fiber-based weak-value amplification against amplitude-type noise

Experiments based on a free-space platform have demonstrated that the weak-value amplification (WVA) technique can provide high sensitivity and precision for optical sensing and metrology. To promote this technique for real-world applications, it is more suitable to implement WVA based on an optical-fiber platform due to the lower cost, smaller scale, and higher stability. In contrast to the free-space platform, the birefringence in optical fiber is strong enough to cause polarization cross talk, and the amplitude-type noise must be taken into account. By theoretical analysis and experimental demonstration, we show that the optic-fiber-based WVA is robust in the presence of amplitude-type noise. In our experiment, even the angular misalignment on optical axes at the interface reaches 0.08 rad, and the sensitivity loss can be maintained at less than 3 dB. Moreover, the main results are valid to a simplified detection scheme that was recently proposed that is more compatible with the future design of optical-fiber-based WVA. Our results indicate the feasibility of implementing WVA based on optical fiber, which provides a possible way for designing optical sensors with higher sensitivity and stability in the future.