The noise-tee - a lightwave device for microwave noise measurements

An innovative lightwave method is proposed to insert noise in electronic circuits in favor of microwave noise measurements. The proposed noise-tee has attractive additional features compared to the use of 50 /spl Omega/ noise sources: 1) the inserted noise level and noise bandwidth is continuously variable over a wide dynamic range; 2) the wideband scaling accuracy of this level, relative to a pre-calibrated level, equals the accuracy of simple DC-current measurements; 3) level-induced impedance variations are negligible, compared to the 20% impedance variation of a commonly used microwave noise source; and 4) noise-tees enable the realization of 100% reflective noise sources, in favor of two-port noise-parameter measurements.