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

Abstract

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 100 μm, and the period of the sampled function is 395 μm. 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.