The thermal shift of dense-wavelength-division-multiplexing (DWDM) filters that is caused by nonconstant temperature during fabrication invokes a spectrum shift and an error in the optical thickness of the layer before the matching layer. The relation between the thermal shift and the optical thickness of the layer before the matching layer was calculated. Five kinds of narrow-bandpass filters were fabricated, and their thermal shifts were measured and compared with the theoretical model. By using this technique, we were able to predict the thermal shift of DWDM filters from the abnormal behavior of the layer before the matching layer during deposition.
© 2006 Optical Society of America
Original Manuscript: February 28, 2005
Revised Manuscript: August 19, 2005
Manuscript Accepted: August 24, 2005
Sheng-Hui Chen, Cheng-Chung Lee, and Chien-Cheng Kuo, "How the monitoring curve is affected by the thermal shift of a filter during deposition," Appl. Opt. 45, 1338-1343 (2006)