An Electro-optical Optical Frequency Divider Based on Thin Film Lithium Niobate

Description

A microwave signal with high temporal stability and low phase noise is extremely important and useful in modern scientific research and application, and frequency divider is a key technology in realizing low-noise microwave signal. Frequency divider plays a pivotal role in various applications in communication systems, and in earlier times, frequency divider was primarily made using different electronic components. With advancing technology, although electronic frequency dividers can achieve both high-speed and wide dynamic range division, they still face challenges such as high-power consumption and poor phase noise performance. Subsequently, photonics technologies are used to address these issues. However, traditional optical frequency dividers can only delineate specific frequency, failing to meet the requirement for precision measurement, and is characterized by complex and bulky setup. Among different optical frequency dividers based on optical frequency comb, electro-optic frequency divider has emerged as a solution to these challenges. Electro-optical frequency divider has straightforward operational mode and potential for integration.  The project has set forth a comprehensive agenda in addressing the scientific challenge on integration, tunability, broad bandwidth, and minimal noise in emerging optical frequency division technology. The work aims to explore the advantages of the thin film lithium niobate platform to develop a wideband tunable electro-optical frequency divider with low phase noise. The generation of optical frequency comb is achieved by cascading distributed Bragg reflector laser with thin film lithium niobate electro-optic modulator. The project will develop an innovative structural framework for electro-optical frequency divider, a refinement of the fabrication process for thin film lithium niobate waveguide device, an exploration of advanced technology to enhance the modulation efficiency and energy conversion efficiency of thin film lithium niobate electro-optical modulator, and an increase in integration stability. The goal is to raise the performance of electro-optic frequency comb significantly. The experimental approach incorporates distributed Bragg reflector laser for achieving wavelength tunability and stable output power, and thin film lithium niobate modulator us interconnected in a cascaded fashion to generate an optical frequency comb, and both essential components can be integrated seamlessly as a miniaturized chip. The chip-level electro-optical frequency divider proposed boasts advantages such as small size, high integration, low power consumption, and enhanced functionality. By utilizing optical frequency division technology for information multiplexing, a significant enhancement in information transmission speed and communication efficiency can be achieved. This aligns with the demand in present and future communication systems. Thus, the proposed electrooptical frequency divider has tremendous prospect for future growth and provides innovative solution to challenges encountered in modern information transmission systems.