Design of 4-port Multi-Channel Lattice-Form Optical Band Pass Filter for Radio over Fiber Application
A coherent 1-input 4-output lattice form optical delay-line circuit with FIR architecture has been synthesized based on the division of the total transfer matrix into unit transfer matrices. The designed1×4optical delay line filter with RF bandpass characteristics has expansion coefficients which are obtained by constrained least square method. The proposed filter provides a RF bandwidth of 475 MHz with center frequencies of 0.7 GHz, 1.8 GHz, 3.1 GHz and 4.3 GHz. Further, 100% power transmittance in the pass bands is realized with a minimum of 60 dB attenuation in the stop bands. Filtering of RF bands in Radio over fiber application is demonstrated using the proposed filter in OptiSystem software.
Keywords-Finite Impulse Response; Optical Delay Line Filters; Constraint least square algorithm; Radio over fiber-optic link; RF band pass filter