K.V. Kalashnikov, A.V. Khudchenko, V.P. Koshelets

A novel superconducting element, High-Harmonic Phase Detector (HPD), intended for phase-locking of a Flux Flow Oscillator (FFO) in a superconducting integrated receiver (SIR) has been proposed and experimentally tested. According to our concept a superconductor-insulator-superconductor (SIS) junction is implemented both for down-conversion of the FFO frequency and for phase-locking of the FFO to an external reference. The regulation bandwidth (BW) of the phase-locking loop (PLL) system based on the HPD as wide as 70 MHz has been measured experimentally; that value several times exceeds the BW of regular PLL systems used for cryogenic oscillators. New PLL system based on HPD synchronizes up to 92% of the emitted FFO power (this parameter is called the spectral ratio, SR) for free running FFO line as wide as 12 MHz The HPD PLL system is simple and compact, therefore it is very promising for future SIR applications, especially for building multi-pixel SIR arrays and for phase-locking of the THz range FFO