  We present and theoretically investigate a dispersion engineered GaP-OI
microresonator containing a partially-etched gap of 250 nm x 410 nm in a 600 nm
x 2990 nm waveguide. This gap enables a 3.25 {\mu}m wide anomalous dispersion
spectral span covering both the near-infrared and the mid-infrared spectra.
This anomalous dispersion is manifested by two mechanisms, being the
hybridization of the fundamental TE modes around 1550 nm and the geometric
dispersion of the higher order TE mode around the 3100 nm wavelengths,
respectively. Two Kerr soliton combs can be numerically generated with 101 GHz
and 97 GHz teeth spacings at these spectral windows. The proposed structure
demonstrates the design flexibility thanks to the partially etched gap and
paves the way towards potential coherent multicolor frequency comb generation
in the emerging GaP-OI platform.
