Abstract

Dispersion and dispersion slope compensation over broadband has been recognized as a crucial technique to improve performance of transmission links in high-speed long-haul Wavelength Division Multiplexing (WDM) transmission systems.^1,2 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).³ 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.^4,5 Despite these merits, HOM 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 microbending⁶ and photo-induced index change⁷ in optical fibers. Recently, a ring type MC based on a tapered hollow optical fiber (HOF) is reported by the authors.⁸

© 2002 Optical Society of America