  Wide bandgap semiconductors are widely used in photonic technologies due to
their advantageous features, such as large optical bandgap, low losses, and
fast operational speeds. Silicon carbide is a prototypical wide bandgap
semiconductor with high optical nonlinearities, large electron transport, and a
high breakdown threshold. Integration of silicon carbide in nonlinear photonics
requires a systematic analysis of the multiphoton contribution to the device
functionality. Here, multiphoton photocurrent in a silicon carbide
photodetector is investigated using phase-modulated femtosecond pulses.
Multiphoton absorption is quantified using a 1030 nm phase-modulated pulsed
laser. Our measurements show that although the bandgap is less than the energy
of three photons, only four-photon absorption has a significant contribution to
the photocurrent. We interpret the four-photon absorption as a direct
transition from the valance to the conduction band at the {\Gamma} point. More
importantly, silicon carbide withstands higher excitation intensities compared
to other wide bandgap semiconductors making it an ideal system for high-power
nonlinear applications.
