Fabrication and Characterization of Low-Loss Gaussian-Like Reversed Ridge Optical Waveguides

A Gaussian-like reversed ridge optical waveguide based on the perfluorinated acrylate polymer is fabricated by an improved UV photolithography with the pre-exposure process. A partially cured thin layer is formed on the lower cladding during the pre-exposure process, which will avoid the effect of the oxygen inhibition in the following UV photolithography. A Gaussian-like groove with a smooth surface is obtained after the pattern development process, which is beneficial to the low-loss waveguide. The transmission loss of 0.25 dB/cm at 1310 nm and 0.45 dB/cm at 1550 nm are measured. The fabricated waveguides transmit several modes, and the inter-channel crosstalk with a core pitch of 250 mu m is below -40 dB at 1310 nm and -49 dB at 1550 nm, which shows the potential in applications of optical interconnection and communications.