A novel design of binary to hexadecimal decoder using titanium diffused LiNbO3 waveguide-based electro optic (Pockel’s effect) Mach-Zehnder interferometer (MZI) has been proposed here. Decoders are digital systems which are used to convert the binary input into the desired output format. The 'Hexadecimal Numeral System' is extensively used in processing units and programming languages. ‘Hexadecimal’ numerals' key benefit is their ability to hold more numbers in less memory. The decoder accepts the binary code after processing it and changes it back into a format that output devices can use. In this paper, the conversion process is proposed using tree net architecture which is very much simpler form than any other mapping. The whole design has been simulated step wise and results are verified by OPTIBPM using beam propagation methodology (BPM). The wafer dimension of footprint of the binary to hexadecimal decoder is 0.4 cm × 800μm and hence it belongs to integrated optics.The proposed photonic decoder's short response time will be useful in commercial research for applications such as memory addressing, speech coding and decoding, line coding and decoding for digital data communication.