Low-Noise Millimeter-Wave Down-Conversion Technology for Chip-Scaled Optical Clocks

This article reports on a millimeter-wave (MM-wave) signal down-conversion system with low phase noise for chip-scaled optical clocks. The system utilizes analog regenerative frequency division, low-noise fractional frequency division, and phase-locked frequency division techniques to down-convert a 100 GHz MM-wave signal to 100 MHz with phase noise of -117 dBc/Hz @100 Hz, -133 dBc/Hz @1 kHz, and 10 MHz with phase noise of -124 dBc/Hz @100 Hz and -143 dBc/Hz @1 kHz. The frequency stability of the signal down-converted to 100 MHz is 5.0 x 10-15 @ 1 s and 1.8 x 10-16 @ 1000 s, while the frequency stability of the 10 MHz signal is 5.7 x 10-14 @ 1 s and 5.9 x 10-16 @1000 s, both of which decrease to the 10-16 level at 10,000 s. This down-conversion system meets the frequency conversion requirements of state-of-the-art chip-based optical clocks and micro-cavity optical combs.