Thin film (TF)-based coupled cavity all-pass filters (CCAP) have the potential for providing compact, low-loss, and highly stable third-order dispersion (TOD) compensation in ultrafast optical fiber transmission systems employing optical time-division multiplexing (OTDM). In this paper, a methodology for designing CCAP filters for TOD compensation is presented. First, we develop a theory necessary for designing the cavity structure, that is, mirror reflectivity and cavity spacing, of CCAP filters. As a next step, we discuss how we can represent such filters as TF devices and demonstrate several TF-layer design examples. Finally, a coupled two-cavity filter is constructed and tested. The filter has a center wavelength that can be varied over a range of 8 nm and can compensate for fiber TOD between 2.0 and 15.5 ps3 over a bandwidth between 3.6 and 1.2 nm, respectively. The peak spectral ripple of the filter is 1.0 dB. The experimentally measured dispersion curves of the filter agree well with the theory.
Mark Jablonski, Yuichi Takushima, and Kazuro Kikuchi, "The Realization of All-Pass Filters for Third-Order Dispersion Compensation in Ultrafast Optical Fiber Transmission Systems," J. Lightwave Technol. 19, 1194- (2001)