Tunable Filters Based on Cascaded Long-Period Polymer Waveguide Gratings

Widely tunable long-period waveguide grating filters

This paper presents a review of the development of long-period waveguide gratings (LPWGs) with focus on the realization of various kinds of tunable devices, such as band-rejection filters, variable attenuators, band-pass filters, and add/drop multiplexers. A number of specific examples are given to demonstrate how the geometry and material flexibility of the optical waveguide technology facilit...

Tunable optical fiber devices based on broadband long-period gratings and pumped microfluidics

This letter describes classes of tunable microfluidic fiber ~mFF! devices that use specially designed long-period gratings in which the phase matching condition is satisfied over a wide spectral range. Dynamic tuning is achieved by electrowetting-based pumping of microfluidic plugs back and forth over the gratings. As specific examples, we demonstrate dynamically tunable broadband attenuators a...

Long Period Fibre Gratings

Tunable Wideband Graphene based Filters in THz Band

In this paper, a procedure for analyzing and designing of tunable wideband band-pass and band-stop graphene based filters in the terahertz band is proposed. These planar wideband plasmonic filters are unique in their kind. With this procedure, it is possible to design filters with the desired functional characteristics in the form of the similar quarter-wavelength resonance stubs. The discontin...

Tunable all-optical negative multitap microwave filters based on uniform fiber Bragg gratings.

We present a novel and simple technique for obtaining transversal filters with negative coefficients by using uniform fiber Bragg gratings. We demonstrate a wide tuning range, good performance, low cost, and easy implementation of multitap filters in an all-optical passive configuration in which negative taps are obtained by use of the transmission of a broadband source through uniform Bragg gr...