Important aspects of a photonic component can be determined by studying the optical modes that the structure supports. While many structures do not vary much over the propagation length and are simple to analyze, other structures vary considerably and require a deeper analysis. This quick tip explores the calculation of mode profiles at specific cross-sections within a knife-edge spot size converter (SSC) structure. More details about the method used can be found in Section 5.D.4 of the BeamPROP manual. The simulation files used can be accessed on the Customer Support Portal.
SSCs are one of most important components in photonic integrated circuits. Knife-edge SSCs have been reported to have low insertion loss for both TE and TM polarization1,2. A knife-edge SSC is composed of a width taper and sharp knife-like tip, and converts the light from a lens-tipped single mode fiber into a silicon wire, or vice versa. For this device, it will be useful to understand the change of the mode profiles along the structure.