Sensors

Design of a Board-Level Integrated Multi-Channel Radio Frequency Source for the Transportable 40Ca+ Ion Optical Clock

Bin Wang, Yuanhang Yang, Huaqing Zhang, Ruming Hu, Haicen Mao, Yao Huang, Kelin Gao, Hua Guan

Published Feb 10, 2025• 0 citations

Abstract

As one of the most accurate instruments in history, the optical clock will be used as the measuring equipment for the next generation of seconds. The demand for miniaturization of optical clock is progressively urgent. In this paper, a multi-channel radio frequency module with a 20% volume of the commercial module is designed and implemented for the transportable 40Ca+ ion optical clock. Based on the double crystal oscillator interlocking technique，1 GHz low-phase noise reference source is developed for direct digital synthesis. By simulation and optimization of the signal link design, a frequency range of the low-phase noise RF signal can reach 0-400 MHz with a 4 μHz resolution. Through two-stage power amplified with different kinds of filters, it can get an output power up to +33 dBm (2 W) at 100 MHz with a 25 dBc/Hz phase noise lower than the commercial module at 1 Hz, and its third harmonic suppression ratio has been reduced by more than 20 dBm at the frequency point of 300 MHz. This multi-channel RF module is used for the power stability and timing control test of 729 nm clock laser, to meet the requirements of the transportable 40Ca+ optical clock. Without this, this module can also be applied to other quantum systems such as quantum absolute gravimeter, quantum gyro and quantum computer.

DOI: 10.3390/s25041044

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