Abstract
A 4-channel planar concave grating device with a flattened spectral response based on SU-8 polymer is presented.
The flattened spectral response is accomplished by using an optimized multi-mode interference coupler as the input
aperture of the device for spectrally separated channels. The mode field distribution in the input plane is controlled
by adjusting the width of input taper coupled to the multi-mode interference coupler. The effects of the input taper
width on the flattened spectral response are demonstrated in detail through simulation results. The devices are
realized by using an SU-8 polymer strip waveguide with a UV lithography technology. Experimental results show
that the flattened spectral response can be easily controlled by adjusting the taper width.
