Experimental study of the self‐imaging phenomenon with weak‐guiding condition

Abstract

AbstractThis paper investigates a self‐imaging phenomenon in a multimode interference (MMI) coupler. In the experiment, different self‐images which are undefined in MMI theory are observed. This undefined self‐image is named the “pseudo‐self‐image ” (PSI) as a matter of convenience. The characteristics of both the single self‐image (0‐dB self‐image: 0‐dB SI), which is defined in MMI theory, and the PSI are compared and analyzed through simulation and experimentation to estimate the applicability of the PSI. Results show that the PSI has an imaging period the same as the 0‐dB SI, and the excess loss and the extinction ratio of the PSI improve more than those of the 0‐dB SI as the imaging period increases. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:2354–2357, 2006;Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.21942