We propose a continuously tunable, dual free spectral range (FSR) photonic microwave notch filter configuration using a high-birefringence linearly chirped fiber Bragg grating (Hi-Bi LCFBG) that is connected in a Sagnac loop using a Hi-Bi coupler. The configuration employs double sideband modulation and can generate two FSRs simultaneously. The larger FSR corresponds to the differential time delay of the Hi-Bi LCFBG and the Hi-Bi pigtails of the coupler; the smaller FSR corresponds to the time delay between the arms of the Sagnac loop. Measured results demonstrate dual FSR, a large notch rejection, and that the FSR is easily tunable by tuning the LCFBG. We also present the filter transfer function for the design. Experimental results agree well with the theoretical analysis.
© 2006 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: May 31, 2006
Revised Manuscript: July 26, 2006
Manuscript Accepted: July 28, 2006
Guoxiang Ning, Ping Shum, Sheel Aditya, and Yandong Gong, "Simultaneous dual free spectral range microwave photonic filter using a high-birefringence chirped grating in a Sagnac loop," J. Opt. Soc. Am. A 24, 188-191 (2007)