Planar waveguide devices for Wavelength Division Multiplexed (WDM) systems are required to perform over a very wide bandwidth. A basic functionality in many larger components is the splitting of power into two or more parts and it is therefore very important to have a reliable, process tolerant design of couplers and splitters that furthermore show wavelength independence over the required bandwidth. To ensure such a capability in COM a joint project was established between COM and IONAS A/S with the goal of designing, fabricating and characterizing wavelength insensitive couplers and splitters. One of the major points in this project has been to link simulated (using BPM programs) and measured performance of a range of different coupler types. After identification of several possible structures they were analyzed for parameter sensitivity and a careful strategy was then used in the lay-out of the first mask. After fabrication, hundreds of couplers and splitters were characterized and compared with simulated results. This process showed that more information was needed for a detailed comparison of simulated and measured parameters, but also that a close comparison is possible. All gathered information from the first lithographic mask has been put into a second mask with a new set of structures as well as a number of components based on coupler designs from the first mask. As examples of obtained results it can be mentioned that couplers with a peak-to-peak splitting ratio variation of less than 0.3dB in the wavelength range from 1500 nm to 1600 nm was realized for both a uniform asymmetric directional coupler and a multi-mode interference coupler. A point symmetric series taper coupler showed a variation of less than 0.2 dB in the same wavelength range, but suffered from much less robustness to process variations. The project ends in the first quarter of 2000 with results from the second mask.
|Effective start/end date||01/01/1999 → …|