TESLA input coupler development

The TeV Superconducting Linear Accelerator (TESLA) requires a RF input coupler capable of delivering 208 kW of 1.3 GWz power to a 9-cell niobium cavity. Various electrical, mechanical, and cryogenic constraints present challenges in the design of such a coupler. Two parallel input coupler development programs are in progress at Fermilab and at DESY. The Fermilab TESLA input coupler design and status is reported.<>