Planar concave grating wavelength demultiplexers with a flattened spectral response are realized based on SU-8 polymer waveguides. The flattened spectral response is accomplished by using an optimized multimode interference (MMI) coupler as the input aperture of the planar waveguide for all spectrally separated channels. The mode field distribution at the input of the planar waveguide is controlled by adjusting the width of the input taper connected to the MMI coupler. The devices are fabricated by cost-effective one-step UV lithography. Experimental results show that the desired flattened spectral response has been realized. The on-chip loss, crosstalk, and nonuniformity of the fabricated device are -14.8, -22, and 2.5 dB, respectively.
- multimode interference coupler
- polymer waveguides
- wavelength division multiplexing
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics