Flat top liquid crystal tunable filter using coupled Fabry-Perot cavities

Abstract

In this paper, a coupled Fabry-Perot cavities filter, using the liquid crystal as the tunable medium, is investigate to achieve tunable flat top filtering performance across the C and L bands. A tandem coupled Fabry-Perot is presented for a tunable passband filter with flat top and minimum ripple in the passband. The overall tuning range of the filter is 172 nm. Several designs are shown with comparable performance to the commercial available 100 GHz fixed single channel filters.

Novel Liquid Crystal Tunable Flat-Top Optical Interleaver

“…Usually the polarization diversity scheme is used in order to reduce polarization related losses. The light that passes through the LC cells should be TE polarized in order to have an LC tuning capability [1,2]. Therefore, a mechanism is needed to assure that the polarization state is TE when the light reaches the LC cells.…”

“…Although several tuning technologies are available such as LiNbO 3 , these devices require high voltage and complex design by using multi-stage birefringence crystal design. Recently, liquid crystals (LCs) have proven broad tuning range in optical tunable filters [1,2]. LC tunable filters offer several advantages such as the low operation voltage, no moving parts, and the large birefringence which enables a wide tuning range.…”

Demonstration of optical beating in the reflectance and transmittance spectra of multilayer structures

“…It is well known that a plane-parallel Fabry-Perot resonator represents a multifunctional device with very wide application range, including filtering of signals [1], optical communications [2,3], sensors [4,5], etc. Usually, it is analysed basing on coherent summation of signals, with consequent calculations of interference and polarisation patterns.…”

Chromatic dispersion analysis and partially compensation for tunable liquid crystal optical interleaver

“…Different tuning techniques are presented such as LiNbO3, using such technique in the tunable devices involves using high voltage and complicated design requirements by using multistage birefringence crystal design [1]. Lately, liquid crystals (LCs) have demonstrated broad tuning range in optical tunable filters [2]- [4]. LC tunable filters propose numerous advantages such as the low operation voltage, no mechanical moving parts, and the large birefringence attribute which enables a broad tuning range.…”