Distributed transverse-force sensing along a single-mode fiber using polarization-analyzing OFDR

We report what we believe to be the first demonstration of a direct distributed transverse-force (TF) sensing along a single-mode fiber (SMF) using a self-built polarization-analyzing optical frequency-domain reflectometry (PA-OFDR). The transverse line-force (TLF) distribution along a SMF can be directly obtained from the absolute measurement of birefringence induced by the TF via photo-elastic effect at different locations along the fiber, without the need of complicated force-to-strain conversion. We show that our system is capable of sensing a weight of merely 0.68 g but yet has a large dynamic range of over 44 dB. In particular, we obtained a maximum detectable TLF of 16.8 N/mm, a minimum detectable TLF of 6.61×10 −4 N/mm, a TLF measurement uncertainty of