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© 2002-2011 IEEE. In this paper, we describe the optimization of transition-edge-sensor (TES) detector arrays for the third-generation camera for the South Pole Telescope. The camera, which contains ~ 16 000 detectors, will make high-angular-resolution maps of the temperature and polarization of the cosmic microwave background. Our key results are scatter in the transition temperature of Ti/Au TESs is reduced by fabricating the TESs on a thin Ti(5 nm)/Au(5 nm) buffer layer and the thermal conductivity of the legs that support our detector islands is dominated by the SiOx dielectric in the microstrip transmission lines that run along the legs.

The relationship between the spectral properties of lasers (phase/frequency noise, coherence, linewidth) and the quality of microwave signals generated by optical heterodyning is described. A 27-142 GHz photonic microwave and millimeter wave synthesizer is presented as an application of these concepts.

We analyze the effect of linewidth reduction systems on the degree of coherence of a laser and the noise levels measured at the output of an interferometer. We show results computed from the power spectral density of frequency noise measured on a DFB fiber laser and a DFB semiconductor laser narrowed with electrical feedback. Results show that the increase of coherence and interferometer noise is significant only over specific range of interferometer length, and that the improvement of interferometer noise might be proportionally much less important than the improvement in linewidth and coherence length.

We describe how the linewidth and coherence length of high purity lasers can be estimated using a frequency counter to replace an optical interferometer of variable length. We also show theoretically and experimentally how such measurements are affected by the finite measurement time