High-Precision Time-Frequency Signal Simultaneous Transfer System via a WDM-Based Fiber Link

oleh: Qi Zang, Honglei Quan, Kan Zhao, Xiang Zhang, Xue Deng, Wenxiang Xue, Faxi Chen, Tao Liu, Ruifang Dong, Shougang Zhang

Format: Article
Diterbitkan: MDPI AG 2021-08-01

Deskripsi

In this paper, we demonstrate a wavelength division multiplexing (WDM)-based system for simultaneously delivering ultra-stable optical frequency reference, 10 GHz microwave frequency reference, and a one pulse per second (1 PPS) time signal via a 50 km fiber network. For each signal, a unique noise cancellation technique is used to maintain their precision. After being compensated, the transfer frequency instability in terms of the overlapping Allan deviation (OADEV) for the optical frequency achieves 2 × 10<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>17</mn></mrow></msup></semantics></math></inline-formula>/s and scales down to 2 × 10<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>20</mn></mrow></msup></semantics></math></inline-formula>/10,000 s, which for the 10 GHz microwave reference, approaches 4 × 10<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>15</mn></mrow></msup></semantics></math></inline-formula>/s and decreases to 1.4 × 10<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>17</mn></mrow></msup></semantics></math></inline-formula>/10,000 s, and the time uncertainty of the 1 PPS time signal along the system is 2.08 ps. In this scheme, specific channels of WDM are, respectively, occupied for different signals to avoid the possible crosstalk interference effect between the transmitted reference signals. To estimate the performance of the above scheme, which is also demonstrated in this 50 km link independent of these signals, the results are similar to that in the case of simultaneous delivery. This work shows that the WDM-based system is a promising method for building a nationwide time and frequency fiber transfer system with a communication optical network.