European Semiconductor Laser Workshop 2004 edition:2004 location:Gotheborg
In widely tunable lasers a high side mode suppression and a large quasi-continuous tuning range can only be obtained with a good grating design. In widely tunable twin-guide lasers, the reflectors and the gain section overlap and this causes a different behavior for the reflectors as compared to passive ones. E.g. using superstructure gratings for DBR lasers, we found that some modes were skipped and no quasi-continuous tuning was obtained due to the influence of the gain on the reflection spectra of the superstructure gratings. Using an optimization method, we have designed a superstructure grating with a flat reflection spectrum even in the presence of gain, such that a good tuning behavior can be guaranteed.