Experimental investigation of relationship between modulation frequency and spatial resolution in OCDR with frequency shifter

We experimentally investigate how the modulation frequency affects the spatial resolution in optical correlation-domain reflectometry (OCDR) with a frequency shifter, a parameter conventionally believed to have no influence. By measuring an open end in a fiber under test at various modulation frequencies and analyzing the reflection peak, we observe that spatial resolution improves at higher modulation frequencies. These results reveal a trade-off between measurement range and resolution in OCDR systems with a frequency shifter. In addition, beat spectrum analysis explores the underlying cause of this behavior.