OPTICAL FIBER-BASED DISPERSION COMPENSATION USING HIGHER-ORDER MODES NEAR CUTOFF

Higher order spatial modes in optical fibers exhibit large, negative c hromatic dispersion when operated near their cutoff wavelength. By usi ng a spatial mode-converter to selectively excite a higher order mode in specially designed multimode fiber, this dispersion can be used to compensate the positive dispersion in conventional single-mode fiber s pans. In this paper, issues related to compensating fiber and mode-con verter design are explored. Experimental measurements in specially des igned two-mode fibers operated in LP11 mode show negative dispersion a s large as -770 ps/nm.km at 1555 nm. Pulse propagation and system expe riments employing spatial mode-converters to excite LP11 mode in a two -mode fiber demonstrate the feasibility of this technique for dispersi on compensation in lightwave systems.