Experimental demonstration of a long-period grating based on the sampling theorem

We demonstrate experimentally the feasibility of a long-period grating whose index change pattern is in the form of sampling a raised-cosine function. We call such a grating a long-period grating based on the sampling theorem (LPGST). The LPGST is thermo-optically induced by an array of electrodes with individual widths. The array period is equal to the sampling period of 100μm, and the period of the sampled function is 395μm. A fabricated polymer long-period waveguide grating using the LPGST has a desired resonance band in its transmission spectrum, which is generated by the periodicity of the sampled function.