M. Bachmann, M. K. Smit, L. B. Solano, P. A. Besse, E. Gini and H. Melchior, "Polarization-Insensitive low-voltage optical waveguide switch using InGaAsP/InP four port Mach-Zehnder interferometer", in Proc. Conf. Optical Fiber Commun. (OFC), San Jose, CA, 1993, pp. 32-33.
A. G. Mignani, A. Mencaglia, M. Brenci and A. Scheggi, "Radially gradient-index lenses: Applications to fiber optics sensors," in Diffractive Optics and Optical Microsystems, New York: Martellucci and Chester, Plenum, 1997.
E. G. Johnson, J. Stack, T. J. Suleski, C. Koehler and W. Delaney, "Fabrication of micro optics on coreless fiber segments", Appl. Opt., vol. 42, no. 5, Feb. 2003.
R. Olshansky, "Mode coupling effects in graded-index optical fibers", Appl. Opt., vol. 14, no. 4, 1975 .
K. Okamoto, Fundamentals of Optical Waveguides, P. L. Kelley, I. P. Kaminow, and G. P. Agrawal, Eds. New York: Academic, 2000, pp. 60-64.
D. Marcuse, "BSTJ", pp. 703-718, 1977.
A. Mehta, W. Mohammed and E. Johnson, "Multimode interference based fiber optic displacement sensor", IEEE Photon. Technol. Lett., Aug. 2003.
K. Kawano and T. Kitoh, Introduction to Optical Waveguide Analysis,: Wiley, 2001, pp. 41-47.
D. Marcuse, Theory of Dielectric Optical Waveguide,: Academic press Inc., 1991.
D. Marcuse, "Mode conversion in optical fibers with monotonically increasing core radius", J. Lightwave Technol., vol. 5, Jan. 1987.
L. B. Soldano and E. C. M. Pennings, "Optical multi-mode interference devices based on self-imaging: Principles and applications", J. Lightwave Technol., vol. 13, Apr. 1995.