Narrow-Linewidth 852-nm DBR-LD with Self-Injection Lock Based on High-Finesse Optical Cavity Filtering
Narrow-Linewidth 852-nm DBR-LD with Self-Injection Lock Based on High-Finesse Optical Cavity Filtering
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DOI：
10.3390/photonics10080936
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发表时间：
2023-07
期刊：
影响因子：
2.4
通讯作者：
Li-li Hao;Rui Chang;Xiaokai Hou;Jun He;Junmin Wang
中科院分区：
文献类型：
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作者：
Li-li Hao;Rui Chang;Xiaokai Hou;Jun He;Junmin Wang
窄线宽激光器具有光谱纯度高、相干长度长、相位噪声低等优点，在原子钟、精密测量、量子计算等领域有着重要的应用。利用超低膨胀（ULE）光学玻璃制作的窄线宽（~ 15 kHz）平凹法布里-珀罗（F-P）腔，将透射光注入到852 nm分布布拉格反射型半导体激光器（DBR-LD）中，其自由运转时的综合线宽为1.67 MHz。随着自注入功率的增加，激光线宽逐渐变窄，注入锁定电流范围逐渐增大。用延迟频移自外差法测得的最宽线宽约为365 Hz，约为自由运转情况下线宽的1/4500。此外，为了表征激光器的相位噪声，我们使用失谐F-P腔测量了自由运行和自注入锁定两种情况下从激光器相位噪声到强度噪声的转换信号。自注入锁定情况下的激光相位噪声显着抑制在0.1-10 MHz的分析频率范围内相比，自由运行的情况下。特别地，在100 kHz的分析频率下，相位噪声被抑制超过30 dB。
Narrow-linewidth lasers have a high spectral purity, long coherent length, and low phase noise, so they have important applications in atomic clocks, precision measurement, and quantum computing. We inject a transmitted laser from a narrow-linewidth (∼15 kHz) flat-concave Fabry–Perot (F-P) cavity made from ultra-low expansion (ULE) optical glass into an 852 nm distributed Bragg reflector-type laser diode (DBR-LD), of which the comprehensive linewidth is 1.67 MHz for the free running case. With an increase in the self-injection power, the laser linewidth gradually narrows, and the injection locking current range gradually increases. The narrowest linewidth measured by the delayed frequency-shifted self-heterodyne (DFSSH) method is about 365 Hz, which is about 1/4500 of the linewidth for the free running case. Moreover, to characterize the laser phase noise, we use a detuned F-P cavity to measure the conversion signal from the laser phase noise to the intensity noise for both the free running case and the self-injection lock case. The laser phase noise for the self-injection lock case is significantly suppressed in the analysis frequency range of 0.1–10 MHz compared to the free running case. In particular, the phase noise is suppressed by more than 30 dB at an analysis frequency of 100 kHz.