  Photon colliders (gamma-gamma, gamma-e) are based on backward Compton
scattering of laser light off the high energy electrons of linear colliders.
Recent study has shown that the gamma-gamma luminosity in the high energy peak
can reach 0.3--0.5 L (e+e-). Typical cross sections of interesting processes in
gamma-gamma collisions are higher than those in e+e- collisions by about one
order of magnitude, so the number of events in gamma-gamma collisions will be
more than that in e+e- collisions. In this paper possible parameters of a
photon collider at TESLA and a laser scheme are briefly discussed.
