  We develop a simple model for the slow lights in Vertical Cavity Surface
Emission Lasers (VCSELs), with the combination of cavity and population
pulsation effects. The dependences of probe signal power, injection bias
current and wavelength detuning for the group delays are demonstrated
numerically and experimentally. Up to 65 ps group delays and up to 10 GHz
modulation frequency can be achieved in the room temperature at the wavelength
of 1.3 $\mu$m. The most significant feature of our VCSEL device is that the
length of active region is only several $\mu$m long. Based on the experimental
parameters of quantum dot VCSEL structures, we show that the resonance effect
of laser cavity plays a significant role to enhance the group delays.
