Multiwavelength Interleaving Filter Based on a Sampled Fiber Bragg Grating Incorporating a Sagnac Loop Interferometer

Abstract

A multiwavelength interleaving filter based on a sampled fiber Bragg grating incorporating a Sagnac loop interferometer is proposed and experimentally demonstrated. A sampled fiber Bragg grating (SFBG) with multiple peaks of reflection is fabricated by using a beam scanning method. By using a Jones matrix method, the transmission spectrum of the Sagnac loop interferometer is analyzed. To control the wavelength spacing of the sampled fiber Bragg grating without a center wavelength shift, we exploit the symmetrical bending technique and control the wavelength spacing of the SFBG. Since the transmission characteristics of the Sagnac loop interferometer is controlled by changing the relative phase difference of two orthogonal polarization modes, the multiple peaks of reflection of the sampled fiber Bragg grating can be tuned by varying the multiple peaks within the Sagnac loop interferometer, and a multiwavelength interleaving filter can be effectively realized.