Wrong time delay of optical fibre in INTERCONNECT
I use a 1.7km optical fibre to propagate light whose wavelength is 1546nm using INTERCONNECT. This fibre can provide about 8us delay theoretically, but the practical time delay is only around 0.1ns in my project. And a warning is: "FIBER_1: Warning: propagation delay at frequency '1.931e+14' Hz is '-3.03032e-10' s, this value should be greater than or equal to zero."
This is a circuit for checking.
Why did this error happen and how can I resolve it?