Abstract: An arrayed waveguide grating (AWG) based triplexer has many advantages including small size and low cost.The commonly used wavelengths in passive optical network (PON) are 1310nm,1490nm and 1550nm,according to ITU G.983 standard.Because of the wide spectral range and very unequal channel spacings,a conventional AWG design cannot produce a satisfactory result.In this paper,a novel triplexer design based on AWG is presented.The spectral periodicity of the grating is utilized in the design so that the first wavelength works at a different diffraction order,and it is mapped to a wavelength that is approximately in the middle of the second and third wavelength channels.This results in a reduced free spectral range (FSR) requirement and almost equal distances between the input/output waveguides.Consequently,the AWG can operate at a higher diffraction order with a smaller device size,compared to the one designed by conventional methods.

Key words: integrated optics, triplexer, arrayed waveguide grating, free spectral range