We presented an attosecond-precision timing detector based on linear-optics. The minimum timing detection floor is 1×10^(-10) fs^2/Hz with only 1-mW input optical power. With this novel technique, the residual dispersion of 5.2-km fiber link is characterized and precisely compensated. Finally, a comprehensive feedback model has been developed to analyze the noise coupling in a long-distance link stabilization system. The simulation results demonstrate an out-of-loop jitter of merely 359 as, integrated at [1 Hz, 1 MHz], with 1-mW input power for each photodetector of our timing detector. Remarkably, the system is capable of maintaining sub-femtosecond precision even at optical power levels as low as 240 nW (for 5.2-km link length), or the link length as long as 20 km (with 1 μW optical power), respectively.