11/01/2011: ISSTT Digest Article "VDI Solid-State LO Sources for Greater than 2 THz"
Abstract Over the last several years, VDI has been developing THz sources based on microwave frequency amplifiers and a cascaded series of frequency multipliers. These are intended to be used as local oscillator sources for astronomical receivers, such as those on the SOFIA airborne observatory. In 2010 a 1.9 THz source with greater than ten microwatts output at room temperature was presented at this conference. VDI has now completed the initial development of similar sources for use at 2.5 and 2.7 THz. The measured output power is about 3 microwatts and is sufficient to fully pump an HEB mixer. This effort required the development of imporoved millimeter-wave varactor multipliers with better thermal grounding for greater power handling, the optimization of the THz multipliers for operation at low power levels and the development of improved assembly and testing techniques. This paper discussed some fo the challenges of achieving useful sources at such high frequency and reviews the results that have been achieved to date, with emphasis on the new 2.51 THz source that has recently been used on the SOFIA aircraft for astronomical observations.