Abstract

In high-speed long-haul wavelength division multiplexing (WDM) transmission systems, dispersion and dispersion slope compensation over broadband have been recognized as an important technique to improve performance of transmission links.¹ One of dispersion compensation techniques is to use a higher-order-mode (HOM) in a few-mode fiber along with a spatial mode converter (MC).² Main advantages would be achievement of a very large negative dispersion in a shorter length of dispersion compensating fiber (DCF). Shorter interaction length can provide a lower insertion loss, and nonlinear effects could be reduced due to its large effective area.³ Despite these merits, HOM dispersion compensating techniques need mating mode converters with a high conversion efficiency and low insertion loss. LP₀₁-LP₁₁ and LP₀₁-LP₀₂ converters have been reported using periodic coupling such as microbending⁴ and photo-induced index change⁵ in optical fibers. Recently, an MC of ring type based on a tapered hollow optical fiber (HOF) and an HOM dispersion compensation technique in a step index LP₀₂ DCF are reported by the authors.^6,7

© 2002 Optical Society of America