Then the mode series of step index planar dielectric waveguide and circular optical fiber are studied, including propagation modes and radiation modes.

The coupled way with globular lens in end side of step index fiber(SIF) is a simple and practical method to increase the coupling efficiency between semiconductor optical resource and SIF.

In order to calculate the equivalent step index of the periodic structure of the cladding holey optical fiber, all-vectorial fundamental space filling mode approach was utilized.