Society of Photo-optical Instrumentation Engineers (SPIE)
Abstract
Stability of a hot-electron bolometer (HEB) heterodyne receiver was investigated at frequencies from 0.6THz to 1.9THz. The Allan variance was measured as a function of the integration time and the Allan time was obtained for HEB mixers of different size, as well as with different types of the local oscillator: FIR laser, multiplier chain, and BWO. We have found that due to stronger dependence of the mixer gain and noise vs mixer bias voltage and current the Allan time is shorter for smaller mixers. At 1.6THz the Allan time is 3 sec for 4x0.4μm^2 bolometer, and 0.15-0.2 sec for 1x0.15μm^2 bolometer. Obtained stability apears to be the same for the FIR laser and the mulitplier chain. The Allan time for smaller bolometers increases to 0.4-0.5sec at 0.6-0.7THz LO frequencies. The influence of the IF chain on the obtained results is also analyzed
