Photon Netw Commun DOI 10.1007/s11107-017-0718-8 ORIGINAL PAPER Design of optical decoder circuits using electro-optic effect inside Mach–Zehnder interferometers for high speed communication Amrindra Pal 1 · Santosh Kumar 1 · Sandeep Sharma 1 Received: 14 April 2016 / Accepted: 29 May 2017 © Springer Science+Business Media New York 2017 Abstract Decoder is a device that allows placing digital information from many inputs to many outputs. Any appli- cation of combinational logic circuit can be implemented by using decoder and external gates. In this paper, 2–4 line and 3–8 line decoder is proposed using electro-optic effect inside lithium–niobate-based Mach–Zehnder interferome- ters (MZIs). The MZI structures have powerful capability to switching an optical input signal to a desired output port. The paper constitutes a mathematical description of the pro- posed device and thereafter simulation using MATLAB. The study is verified using beam propagation method. Keywords Electro-optic effect · Mach–Zehnder interfer- ometer · Beam propagation method · Optical computing · Decoder 1 Introduction Optical waveguides and switching devices are the build- ing blocks of photonics integrated circuits. They are used as splitters, multiplexer and de-multiplexer for optical sig- nals. Recently, their applications have been realized in almost all the fields of optical communication, data transmission, video transmission and optical networking. Nowadays, an increasing attention has been given toward the study of opti- cal waveguides and switching devices as they are very useful for wavelength division multiplexing (WDM) systems. Opti- cal communication technology has become the sole way B Amrindra Pal amrindra.pal123@gmail.com 1 Photonics Lab, Department of Electronics and Communication Engineering, DIT University, Dehradun 248009, India to achieve large transmission capacity with longer trans- mission distance. To achieve higher speed of data transfer, signal should be in the optical form. Semiconductor optical amplifier–Mach–Zehnder interferometer (SOA–MZI) has played a significant role in the field of ultra-fast optical signal processing [1]. Many researchers have analyzed the perfor- mance of SOA–MZI-based switches and XOR gate through numerical simulations to generalize the optimal parame- ters as well as the suitable operation conditions [2–4]. A Mach–Zehnder interferometer (MZI) wavelength converter consisting of integrated semiconductor optical amplifiers (SOAs) is utilized to implement all-optical modulation for- mat conversion and divider circuit [5, 6]. These switches and gates are having the limitation of speed due to saturation effect of SOA. In the above discussion, the switch has a restricted speed due to saturation effect of SOA. Therefore, it has been thought of great interest to take up this problem and give an alternative explanation for the realization of high speed switch by using MZI, which may not required SOA. Due to above limiting factor observed in performance of high speed switch, it is tried to optimize the performance of above mentioned devices for the purpose to realize high speed oper- ation. Mach–Zehnder interferometer based on electro-optic effect in LiNbO 3 seems to be a promising solution, because of its characteristic features of compact size, thermal stabil- ity, re-configurability, integration potential, low latency and low power consumption [7–9]. The fundamentals of electro- optic (EO) effect and mathematical description of MZI is well explained in Raghuwanshi et al. [10]. Owing to which various authors have shown their keen interest in implementing the number of combinational and sequential circuits [8, 11–19] using electro-optic effect in LiNbO 3 -based MZI. In this paper, a 2–4 line and 3–8 line decoder is designed for high speed communication. Section 2 explains the schematic diagram and working of decoders. Section 3 123