16 × 1 Integrated filter array in the MIR region prepared by using a combinatorial etching technique

A combinatorial etching technique is introduced to prepare integrated narrow bandpass filters in the mid-infrared (MIR) region. In this region, a 16×1 filter array has been fabricated successfully with two deposition processes combined with the combinatorial etching technique. The pass bands of the 16 filter elements range from 2.534 to 2.859 μm with bandwidth (BW _{3 dB}) less than 0.013 μm (BW_{3 dB}/λ ≤ 0.48%). The insertion loss of the pass bands is between 1.75 and 3.43 dB. The results show that the technique is effective for the fabrication of filter arrays in the MIR region and can be extended to most of the important optical regions.