H. Mak and H. Tanagawa, "High-extinction directional coupler switches by compensation and elimination methods," J. Lightwave Technol., vol. 12, pp. 899-908, May 1994.
I. P. Januar, R. J. Feuerstein, A. R. Mickelson, and J. R. Sauer, "Wavelength sensitivity in directional couplers" J. Lightwave Technol., vol. 10, pp. 1202-1209, Sept. 1992; see also, I. P. Januar, Characteristics of Integrated Optical Devices and Structures, Ph.D. dissertation, Univ. Colorado, Boulder, Nov. 1992.
S. Lin, W. Feng, J. C. Powelson, R. J. Feuerstein, L. Bintz, D. Tomic, and A. R. Mickelson, "Crosstalk on active directional couplers," J. Lightwave Technol., vol. 14, pp. 2012-2025, Sept. 1996.
I. P. Januar and A. R. Mickelson, "Characteristics of S-shaped waveguide structures by the annealed proton exchange process in LiNbO3" J. Lightwave Technol., vol. 11, pp. 2044-2051, Dec. 1993; see also I. P. Januar, Characteristics of Integrated Optical Devices and Structures, Ph.D. dissertation, Univ. Colorado, Boulder, Nov. 1992.
V. R. Chinni, T. C. Huang, P.-K. A. Wai, C. R. Menyuk, and G. J. Simonis, "Crosstalk in a lossy directional coupler switch," J. Lightwave Technol., vol. 13, pp. 1530-1535, July 1995.
See, for example, L. Wang, K. Iiyama, F. Tsukada, N. Yoshida, and K. Hayashi, "Loss measurement in optical waveguide devices by coherent frequency-modulated continuous-wave reflectometry," Opt. Lett., vol. 18, no. 13, pp. 1095-1097, 1993; see also U. B. Ramabadran, H. E. Jackson, and J. T. Boyd, "Optical waveguides fabricated by ion implantation of Si^+ and N^+ in SiO_2olon A Raman investigation," Appl. Opt., vol. 32, no. 3, pp. 313-317, 1993; see also Y. Okamura, A. Miki, and S. Yamamoto, "Experimental demonstration of optical field evolution in waveguide junctions by using a video camera observing system," Appl. Opt., vol. 29, no. 34, pp. 5086-5089, 1990; see also A. Miki, Y. Okamura, and S. Yamamoto, "Optical waveguide directional coupler measurements using a microcomputer-assisted TV camera system," J. Lightwave Technol., vol. 7, pp. 1912-1918, Dec. 1989; see also R. K. Hickernell, D. R. Larson, R. J. Phelan, Jr., and L. E. Larson, "Waveguide loss measurement using photothermal deflection," Appl. Opt., vo l. 27, no. 13, pp. 2636-2638, 1988; see also S. A. M. Al-Chalabi and B. L. Weiss, "A comparison of prism coupling and scattered light waveguide attenuation measurements," Int. J. Electron., vol. 62, no. 1, pp. 147-151, 1987.