We fabricated solid thin film composed of deoxyribonucleic acid (DNA) complexes based on cetyltrimethylammonium (DNA-CTMA). We developed a re-crystallization process that can reduce the hydroxyl contents significantly, which were confirmed by the Raman spectra measurements. DNA-CTMA film was deposited on a polydimethylsiloxane (PDMS) channel to form a ridge waveguide.