ABSTRACTWe have developed a single-mode optical waveguide utilizing siloxane polymer on ceramic substrate for opto-electronic multichip modules (O/E-MCM) to operate Tera bps. In this paper, we describe group velocity dispersion for the optical waveguide utilizing siloxane polymer on ceramic substrate. The group velocity dispersion becomes 0 fs/cm·nm at around 1310 nm and 1530 nm wavelength. There is abnormal dispersion at around 1530 nm. The results showed that the group velocity dispersion of the optical waveguide was significantly related to the absorption spectrum of siloxane polymer. The group velocity dispersion of the optical waveguide is about 0.4 fs/cm·nm at 1550 nm wavelength. When a 500 femto seconds optical pulse, which has 16 nm for spectrum width, pass through the 50 mm long optical waveguide, pulse expansion is estimated 20 fs/cm·nm. This expansion of spectrum is well to distinguish femto seconds optical signals. Thus, the optical waveguide utilizing siloxane polymer is capable for femto seconds optical pulses transmission.