Pulsar Observations with the Fermi Large Area Telescope
  The Large Area Telescope (LAT) on Fermi, launched on 2008 June 11, is a space
telescope to explore the high energy gamma-ray universe. The instrument covers
the energy range from 20 MeV to 300 GeV with greatly improved sensitivity and
ability to localize gamma-ray point sources. It detects gamma-rays through
conversion to electron-positron pairs and measurement of their direction in a
tracker and their energy in a calorimeter.
  This thesis presents the gamma-ray light curves and the phase-resolved
spectral measurements of radio-loud gamma-ray pulsars detected by the LAT. The
measurement of pulsar spectral parameters (i.e. integrated flux, spectral
index, and energy cut-off) depends on the instrument response functions (IRFs).
A method developed for the on-orbit validation of the effective area is
presented using the Vela pulsar. The cut efficiencies between the real data and
the simulated data are compared at each stage of the background rejection. The
results are then propagated to the IRFs, allowing the systematic uncertainties
of the spectral parameters to be estimated.
  The last part of this thesis presents the discoveries, using both the LAT
observations and the radio and X ephemeredes, of new individual gamma-ray
pulsars such as PSR J0205+6449, and the Vela-like pulsars J2229+6114 and
J1048-5832. Timing and spectral analysis are investigated in order to constrain
the gamma-ray emission model. In addition, we discuss the properties of a large
population of gamma-ray pulsars detected by the LAT, including normal pulsars,
and millisecond pulsars.
