Abstract

We present a novel differential mode delay (DMD) measurement technique for a conventional multimode fiber (MMF) using Fourier-domain low-coherence interferometry (fLCI) with a modified Mach-Zenhder interferomter. An optical spectrum analyzer and a broadband source were used to obtain time resolved optical interference signal. The measured interference signal is Fourier transformed to obtain time delay information. A scanning offset launching method is used to excite every available mode in an MMF. A conventional MMF with its length of 9 m is tested to demonstrate the validity of our proposed method. The experimental results of our proposed method agree well with results obtained using a conventional timedomain measurement method. Our proposed measurement method can measure a short length multimode optical fiber with temporal DMD resolution better than 0.11 ps / m.