We present an optical finite impulse response (FIR) filter de-sign method. Based on crystal birefringence, an optical FIR filter can be designed to produce arbitrary spectrum output. A mathematic model of the optical FIR filter is introduced from the FIR theory. Details of the mapping relationship between an FIR filter and an optical filter are ana-lyzed. A classical FIR filter design method is directly applied. After using the optical backward transfer method to implement the optical configura-tion, a design of a green/magenta broadband filter is discussed. The experiment results demonstrate that the theoretical simulation is in ac-cordance with the experiment. © 2003 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.1586289] Subject terms: finite impulse response filter; optical finite impulse response filter; crystal birefringence; extended Jones matrix; arbitrary spectrum output. Paper 020542 received Dec. 13, 2002; revised manuscript received Jan. 22, 2003; accepted for publication Jan. 22, 2003.