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In the direction of technological optimization, superconducting electrodes such as niobium nitride( NbN) and yttrium barium copper oxygen( YBCO) can first be explored to replace existing aluminum electrodes, utilizing the near zero resistance characteristics of superconducting materials to reduce microwave transmission losses, which is expected to decrease from the current 0.5 dB / cm to below 0.1 dB / cm. By combining the refined design of electrode structures, it is expected to increase the modulation bandwidth from 70 GHz to over 100 GHz, while further reducing the half wave voltage length product( V p L) tobelow 2.5 Vcm, meeting the higher performance requirements of ultra high speed optical communication and microwave photonics.
Secondly, a micro heater can be integrated to construct a temperature closed-loop control module. By real-time feedback adjustment of the working temperature of MRR and DD-MZM, the FSR drift caused by environmental temperature fluctuations( �20 ~ 60 ℃) can be suppressed from ± 5 GHz to within ± 1 GHz, and the frequency doubling efficiency fluctuation can be controlled below 1 %, significantly improving the long-term stability of the device in extreme environments. In addition, the bonding process of Si 3 N 4-TFLN heterojunction can be optimized to further reduce the interface scattering loss from the current 0.3 dB / cm to 0.1 dB / cm. Combining the Q-factor optimization of MRR, such as introducing Euler bending structure to reduce bending loss, it is expected to increase the frequency doubling efficiency from 15 % to over 20 %, breaking through the nonlinear performance bottleneck of existing TFLN devices.
In terms of the potential for scenario implementation, this device can serve as a core module for multi wavelength optical sub sources in the field of quantum communication: using high-precision phase modulation( phase accuracy ± 0.05 rad) of DD-MZM to achieve flexible control of photon quantum states, combined with the frequency doubling function of MRR, the telecom band( 1550 nm) photons are converted to visible light( 775 nm) or near-infrared( 1064 nm) bands, providing a multi band compatible integrated photon source for quantum entanglement distribution and quantum key distribution( QKD) systems, solving the problems of large volume and poor synchronization of traditional discrete light sources. In the 5G / 6G microwave photon link, this device can achieve an integrated function of“ microwave signal modulation frequency doubling optical transmission”: a modulation bandwidth of 70 GHz can cover the 5G millimeter wave frequency band( 24 – 40 GHz) and 6G candidate frequency band( 60 – 70 GHz), a MRR-FSR of 120 GHz can support efficient frequency doubling of microwave signals( such as doubling 28 GHz signals to 56 GHz), and a miniaturized area of 3.648 mm 2 can meet the high-density integration requirements of base stations and core networks, effectively reducing the volume and power consumption of microwave photon links and providing key support for ultra high speed signal processing in next-generation wireless communication. In addition, the device can also be extended to the field of LiDAR, using phase modulation to achieve high-precision scanning of the beam, combined with frequency doubling function to adapt to the wavelength requirements of different detection scenarios( such as near-infrared for short-range detection and visible light for high-precision imaging), promoting the integration and miniaturization development of LiDAR systems.
Acknowledgments
The authors have reviewed and edited the output and take full responsibility for the content of this publication.
Funding
This research was funded by Youth Independent Innovation Research Foundation, grant number KYSZJKQTZQ23013. Conflicts of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
Data availability statement This article has no associated data generated. Author contribution statement
All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Ting An, Guizhou Lv and Yunfeng Jiang. The first draft of the manuscript was written by Ting An and Limin Liu. The format and content of drafts are regulated byYunfeng Jiang. All authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.
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