欧姆热调谐光学微泡谐振腔光频梳研究

Ohmic Thermal Tuning Optical Frequency Comb in Microbubble Resonator

光学微腔光频梳(OpticalFrequencyComb,OFC)具有阈值低、结构紧凑以及易于芯片集成等优势,在精密光谱测量和原子钟等研究领域具有非常好的应用前景。尽管关于OFC的研究已经取得丰富的成果,但大多数OFC具有稀疏的梳齿模式,不利于OFC的调谐。鉴于此,利用高品质因子光学微泡谐振腔的欧姆热实现OFC的调谐。首先理论上分析微腔色散原理,并计算微腔色散参量与微泡谐振腔尺寸的关系。然后制备直径为275μm和品质因子高达1.2×10^(8)的微泡谐振腔,在反常色散区通过连续激光泵浦来获得宽带OFC。最后将微金丝集成于直径为297.5μm的微泡谐振腔中空通道内并置于电路中,利用电流控制器为微金丝施加电流来产生欧姆热以实现OFC的调谐,调谐范围达到0.21nm。

The optical microcavity based optical frequency comb(OFC)has the advantages of low threshold,compact structure,and easy chip integration,and has very good application prospects in the research fields of precision spectroscopy and atomic clocks.Although the research on OFC has achieved rich results,most OFCs have a sparse comb-tooth pattern,which is not conducive to the tuning of OFC.In view of this,the ohmic heat of the high quality factor optical microbubble resonant cavity is used to realize the tuning of the OFC.First,we theoretically analyze the principle of microcavity dispersion,and calculate the relationship between the microcavity dispersion parameter and the size of the microbubble cavity.Then,a microbubble resonator with a diameter of 275μm and a quality factor of 1.2×10^(8)is prepared,a broadband OFC is obtained by continuous laser pumping in the anomalous dispersion region.Finally,the Au microwire is integrated into the empty channel in the microbubble resonant cavity with a diameter of 297.5μm and placed in the circuit.The current controller is used to apply current to the Au microwire to generate ohmic heat to realize the tuning of the OFC.The range reaches 0.21 nm.