G. Mueller, D. Reitze, H. Rong, D. Tanner, S. Yoshida

The Input Optics for LIGO prepares the light from the pre-stabilized laser for the interferometer.  It consists of sideband modulation, mode matching, a mode cleaner for beam jitter suppression and frequency stabilization, and mode characterization diagnostics. The construction and characterization of the LIGO Input Optics for the 2 km Hanford WA interferometer has progressed substantially within the past six months. In this talk, we report on the status of the Input Optics with an emphasis on i) performance characteristics of the 15 m mode cleaner, and ii) mode matching measurements using a novel heterodyne technique to measure and improve the mode coupling into an optical cavity.