I mainly discuss collocation-based spectral element method and its application to compute optical waveguides. There are few literature on how to implement collocation-based spectral element method. I describe how to apply the continuous collocation-based spectral element method to numerically solve the boundary value problems of the elliptic equations in detail. One benefit of the method lies on that it can achieve comparably simple programming and yet can be used to solve complicated problem. This is undoubtedly a value of this method. Application of the method to study optical waveguide problem are presented. Hints for constructing nodal continuous/ discontinuous nodal Galerkin spectral methods are suggested too.