Optical power limiting in integrated optics using nonlinear segmented waveguides

Summary form only given. Segmented waveguides are formed by a periodic structure of high index refractive segments embedded in a low refractive index substrate. The use of such structures for power limiting is based on the fact that their intrinsic propagation losses are very sensitive to the guiding parameters. Increasing the index difference /spl delta/n between the guiding parts of the structure and the substrate can lead to dramatic effects on the losses. Since an optical power dependent index change in the guiding and non-guiding parts of the structure can be obtained using the Kerr effect or a /spl chi//sup 2/ cascading process, the structure can act as an optical limiter. We have analyzed a waveguide containing configuration with a highly nonlinear Kerr-type contrast since the nonlinearity is present only in the high index segments and null in the surrounding media which can be made using a cascaded /spl chi//sup 2/ process in the segments. We have also considered the case of using a dopant in the high index segments which increases the Kerr-type nonlinear contrast but without destroying the Kerr effect in the substrate. The expected behavior of optical limiting is still valid but at the expense of an increasing input power.