  We extend the range of quantum dot (QD) emission energies where electron and
hole $g$ factors have been measured to the practically important telecom range.
The spin dynamics in InAs/In$_{0.53}$Al$_{0.24}$Ga$_{0.23}$As self-assembled
QDs with emission wavelengths at about 1.6 $\mu$m grown on InP substrate is
investigated by pump-probe Faraday rotation spectroscopy in a magnetic field.
Pronounced oscillations on two different frequencies, corresponding to the QD
electron and hole spin precessions about the field are observed from which the
corresponding $g$ factors are determined. The electron $g$ factor of about
$-1.9$ has the largest negative value so far measured for III-V QDs by optical
methods. This value, as well as the $g$ factors reported for other III-V QDs,
differ from those expected for bulk semiconductors at the same emission
energies, and this difference increases significantly for decreasing energies.
