Optical Phase Lock Loop as High-Quality Tuneable Filter for Optical Frequency Comb Line Selection
Optical Phase Lock Loop as High-Quality Tuneable Filter for Optical Frequency Comb Line Selection
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DOI：
10.1109/jlt.2018.2848961
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发表时间：
2018-10-01
影响因子：
4.7
通讯作者：
Seeds, Alwyn J.
中科院分区：
文献类型：
--
作者：
Balakier, Katarzyna;Shams, Haymen;Seeds, Alwyn J.
本文描述了一种作为超选择性光学频率梳状线滤波器实现的光学锁相环 (OPLL)。 OPLL 基于首次通过通用代工方法制造的光子集成电路 (PIC)。 PIC 包含分布式布拉格反射 (DBR) 激光器，其频率和相位通过参考光学频率梳发生器来稳定。 OPLL输出为单模DBR激光线； OPLL 滤波器输出处的其他梳状线和噪声被衰减至低于 OPLL 滤波器输出线峰值功率 > 58 dB。 OPLL 带宽高达 200 MHz，滤波器品质因数大于 1,000,000。 DBR 激光器的调谐频率可超过 1 THz (8 nm)，从而可以选择不同的梳线。还可以锁定频率偏移在 4 至 12 GHz 之间精确选择的梳状线。 DBR 激光器和梳状线之间的相干性通过测量外差信号残余相位噪声水平来证明，在距载波 5 kHz 偏移时，该残余相位噪声水平低于 -100 dBc/Hz。 OPLL 滤波器的输出可比滤波器隔离的梳状线的峰值功率高出 6 dB。这种光学增益是一种独特的特性，可以显着提高通信或光谱系统的信噪比。该 OPLL 预计用于高纯度、可调谐微波、毫米波和太赫兹产生。
This paper describes an optical phase lock loop (OPLL) implemented as an ultraselective optical frequency comb line filter. The OPLL is based on a photonic integrated circuit (PIC) fabricated for the first time through a generic foundry approach. The PIC contains a distributed Bragg reflector (DBR) laser whose frequency and phase are stabilized by reference to an optical frequency comb generator. The OPLL output is a single-mode DBR laser line; other comb lines and noise at the output of the OPLL filter are attenuated by > 58 dB below the peak power of the OPLL-filter output line. The OPLL bandwidth is up to 200 MHz, giving a filter quality factor greater than 1,000,000. The DBR laser can be tuned over 1 THz (8 nm), enabling different comb lines to be selected. Locking to a comb line with a frequency offset precisely selectable between 4 and 12 GHz is also possible. The coherence between the DBR laser and the comb lines is demonstrated by measurements of the heterodyne signal residual phase noise level, which is below -100 dBc/Hz at 5 kHz offset from the carrier. The OPLL-filter output can be up to 6 dB higher than the peak power of the comb line to be isolated by the filter. This optical gain is a unique characteristic which can significantly improve the SNR of communication or spectroscopy systems. This OPLL is envisaged to be used for high purity, tuneable microwave, millimetre-wave, and THz generation.