1/f Noise in the Mixer Based on Schottky Diode

Fluctuations of Schottky diode parameters in a structure of the mixer are investigated. We have used our original measurement data of [Formula: see text] noise in the diode at forward current, which were reported somewhat earlier. These fluctuations are manifested in two ways. At the first, they lead to fluctuations in the transfer factor that is lead to the amplitude fluctuations in the signal at intermediate frequency. The estimation of spectrum of relative fluctuations in the transfer factor of the mixer is executed. Dependences of both the spectrum of these fluctuations on the current through the diode and on the amplitude of the heterodyne signal are investigated. At the second, fluctuations in parameters of the diode lead to occurrence of [Formula: see text] noise in the output voltage. This noise limits the sensitivity of the mixer to the received signal.

Orthogonal Dual-Frequency SOA-Fiber Laser

In order to develop a new orthogonal dual-frequency laser, we studied a fiber ring laser using a SOA (semiconductor optical amplifier) and aim to apply it to a novel light source for optical heterodyne interferometry. The frequency difference was generated by a linear or circular birefringent medium inserted into the ring cavity. To obtain heterodyne signal optical and electrical filters were introduced.

A Short-Range Millimeter-Wave Detector System

This paper is focused on a millimeter-wave detector system that works at self-heterodyne mode. The detector antenna and MMW front-end are integrated and a weak heterodyne signal is amplified with a low-noise amplifier. After high-speed sampled with a high-speed A/D, digital signal are processed in a FPGA. Some experiment results are shown finally.