Digital signal processing techniques are used for synthesizing tunable optical filters with variable bandwidth and centered reference frequency including the tunability of the low-pass, high-pass, bandpass, and bandstop optical filters. Potential applications of such filters are discussed, and the design techniques and properties of recursive digital filters are outlined. The basic filter structures, namely, the first-order all-pole optical filter (FOAPOF) and the first-order all-zero optical filter (FOAZOF), are described, and finally the design process of tunable optical filters and the designs of the second-order Butterworth low-pass, high-pass, bandpass, and bandstop tunable optical filters are presented. Indeed, we identify that the all-zero and all-pole networks are equivalent with well known principles of optics of interference and resonance, respectively. It is thus very straightforward to implement tunable optical filters, which is a unique feature.
© 2009 Optical Society of America
Fourier Optics and Signal Processing
Original Manuscript: January 26, 2009
Revised Manuscript: March 30, 2009
Manuscript Accepted: April 17, 2009
Published: May 11, 2009
Le Nguyen Binh, "Tunable photonic filters: a digital signal processing design approach," Appl. Opt. 48, 2799-2810 (2009)