A novel technology for fabricating gratings of any chirp characteristics by design

Summary form only given. We demonstrated that, by using the elastomer PDMS (polydimethylsiloxane), one can form gratings of any desired chirp characteristics by simply designing the geometric profile of the material. Using two kinds of linearly tapered geometries as examples, one can generate non-linear (∼1/x) and quasi-linear chirped grating profiles. Following the design concept, we can achieve any kind of chirp profile by properly choosing the geometry of the device and the magnitude of the stretching force along the grating axis. Furthermore, the chirp profile can be dynamically changed by tuning the stretching force. This simple and low cost device technology holds promise for WDM and sensing applications. We further focus on incorporating the chirped grating into PDMS waveguide structures consisting of different compositions of PDMS pre-polymer and curing agent to create a refractive index difference between the core and cladding layers.