Dual carrier suppression interferometer for measurement of phase noise

A new scheme for phase noise measurement is presented, based on dual stage suppression of the carrier and synchronous detection of the noise sidebands of the device being tested. This scheme features real time output and intrinsically low instrument flicker. A prototype shows a residual flicker as low as -160 dBrad²/Hz at 1 Hz off the 100 MHz carrier. Other implementations are possible, from 1 MHz to several gigahertz. Applications include the noise characterisation of components and the design of innovative ultrastable oscillators