Abstract

We present a technique for coherence transfer of laser light through a branching fiber link, where the optical phase noise induced by environmental perturbations via the fiber link is passively compensated by remote users without the requirements of any active servo components. At each remote site, an acousto-optic modulator (AOM) is simultaneously taken as a frequency distinguisher for distinguishing its unique frequency from other sites’ and as an optical actuator for compensating the phase noise coming from the optical fiber. With this configuration, we incorporate a long outside loop path consisting of a fiber-pigtailed AOM into the loop, enabling the significant reduction of the outside loop phase noise in the passive way. To further address the residual out-of-loop phase noise coming from the interferometer and the two-way optical frequency comparison setup, we design a low-noise active temperature stabilization system. Measurements with a back-to-back system show that the stability in our stabilization system is $2\times 10^{-16}$ at 1 s, reaching $2\times 10^{-20}$ after 10,000s. Adopting these techniques, we demonstrate transfer of a laser light through a branching fiber network with 50 km and 145 km two fiber links. After being compensated for the 145 km fiber link, the relative frequency instability is $3.4\times 10^{-15}$ at the 1 s averaging time and scales down to $3.7\times 10^{-19}$ at the 10,000 s averaging time. This proposed technique is suitable for the simultaneous transfer of an optical signal to a number of independent users within a local area.

Fiber-optic radio frequency transfer based on passive phase noise compensation with frequency dividing and filtering

Rui Huang, Guiling Wu, Hongwei Li, and Jianping Chen
Opt. Lett. 41(3) 626-629 (2016)

Multi-access fiber-optic radio frequency transfer with passive phase noise compensation

Hongwei Li, Guiling Wu, Jiapeng Zhang, Jianguo Shen, and Jianping Chen
Opt. Lett. 41(24) 5672-5675 (2016)

Passive optical phase noise cancellation

Liang Hu, Xueyang Tian, Guiling Wu, and Jianping Chen
Opt. Lett. 45(15) 4308-4311 (2020)

Coherence transfer of subhertz-linewidth laser light via an optical fiber noise compensated by remote users

Lifei Wu, Yanyi Jiang, Chaoqun Ma, Hongfu Yu, Zhiyi Bi, and Longsheng Ma
Opt. Lett. 41(18) 4368-4371 (2016)

High-precision optical frequency transfer over a 96 km urban fiber link

Lei Liu, Nan Cheng, Jialiang Wang, Qian Cao, Zhou Tong, Kang Ying, and Youzhen Gui
Appl. Opt. 62(3) 683-687 (2023)