In this paper,we propose and experimentally demonstrate a method to realize a polarization detector by using a commercially available polymethyl methacrylate(PMMA) pipe.An asymmetric polarization-related structure is fabricated by etching different grating structures on the external surface of the pipe.The results show that when the pipe rotates up to 90°,the peak of the transmission spectrum can evidently shift towards the low frequency,which means the pipe with grating structures can serve as a polarization detector.This design possesses the merits of a simple structure and easy fabrication. In this paper, we propose and experimentally demonstrate a method to realize a polarization detector by using a commercially available polymethyl methacrylate (PMMA) pipe. An asymmetric polarization-related structure is fabricated by etching different grating structures on the external surface of the pipe. results show that when the pipe rotates up to 90 °, the peak of the transmission spectrum can evidently shift towards the low frequency, which means the pipe with grating structures can serve as a polarization detector. This design possesses the merits of a simple structure and easy fabrication.