  In a charge tunable device, we investigate the fine structure splitting of
neutral excitons in single long-wavelength (1.1\mu m < \lambda < 1.3 \mu m)
InGaAs quantum dots as a function of external uniaxial strain. Nominal fine
structure splittings between 16 and 136 \mu eV are measured and manipulated. We
observe varied response of the splitting to the external strain, including
positive and negative tuning slopes, different tuning ranges, and linear and
parabolic dependencies, indicating that these physical parameters depend
strongly on the unique microscopic structure of the individual quantum dot. To
better understand the experimental results, we apply a phenomenological model
describing the exciton polarization and fine-structure splitting under uniaxial
strain. The model predicts that, with an increased experimental strain tuning
range, the fine-structure can be effectively canceled for select telecom
wavelength dots using uniaxial strain. These results are promising for the
generation of on-demand entangled photon pairs at telecom wavelengths.
