[1] Fornier Bousquet A, Kowalczyk R. Optical filters: Monitoring process allowing the auto-correction of thickness errors. Thin Solid Films, 1972, 13: 285 - 290

[2] Christi Madsen K, Jian Zhao H. Optical Filter Design and Analysis. New York: John Wiley & Sons, Inc., 1999

[3] Zoller A, Boos M, Herrmann R, et al. Optical thickness monitoring of dielectric optical filters using a new in-situ phometer with high signal resolution and excellent long-term-stability. SPIE, 1988, 1019: 106- 113

[4] Willey R R. Achieving narrow bandpass filters which meet the requirements for DWDM. Thin Solid Films, 2001, 398/399: 1 - 9

[5] Pan J J, Zhou F Q, Zhou M. Thin films improve 50GHz DWDM devices. Laser Focus World, 2002, 38: 111 - 116