The synthesis algorithm is presented for 1-input 3-output optical delay-line circuit with IIR architectures. The authors recently reported circuit structure and subsequent synthesis algorithm for r 1x3optical delay-line circuit that can realize any arbitrary frequency characteristics of FIR optical filters. In the present paper, circuit configuration and synthesis mechanism for 1x3optical delay-line circuit with ring waveguides is proposed that can realize similar filter characteristics as infinite impulse response (IIR) digital filters. The Synthesis algorithm is based on division of the total transfer matrix into basic unit blocks. A three-port IIR optical filter has been synthesized using the design data of IIR digital filter. In addition, in this article recent patents are also discussed.