Liquid crystal-based tunable photodetector operating in the telecom C-band

Abstract

Liquid crystal (LC) microcells monolithically integrated on the surface of InGaAs based photodiodes (PDs) are demonstrated. These LC microcells acting as tunable Fabry-Perot filters exhibit a wavelength tunability of more than 100 nm around 1550 nm with less than 10V applied voltage. Using a tunable laser operating in the S and C bands, photocurrent measurements are performed. On a 70 nm tuning range covered with a driving voltage lower than 7V, the average sensitivity for the PD is 0.4 A/W and the spectral linewidth of the LC filter remains constant, showing a FWHM of 1.5 nm. Finally, the emission spectrum from an Er-doped fiber is acquired by using this tunable PD as a micro-spectrometer.

Unprecedented Wavelength Dependence of an Antimony Chalcohalide Photovoltaic Device

“…In previous studies, color-selective detection was achieved using a liquid crystal color filter or multijunction devices or horizontally lied two active materials. [4,42,43,59] However, continuous color recognition by a single-junction cell is unprecedented and notable.…”

Anisotropic Transverse Confinement Design for Electrically Pumped 850 nm VCSELs Tuned by an Intra Cavity Liquid-Crystal Cell

“…Most of all, our approach seems a bit more mature because different intermediate steps of the technology have been already demonstrated. The use of a single SU-8 nanograting for LC alignment and of polymer-based walls to define the LC microcells made indeed the fabrication of first efficient tunable optical devices possible, like passive Fabry-Pérot filters [17], tunable III-V photodiodes (with electrodes and microreliefs) [18]. More recently, optically-pumped 1.55 µm VCSELs [14] were demonstrated within our technology, displaying a continuous tuning of about 23.5 nm in CW.…”

Bistable Color‐Tunable Liquid Crystal Fiber by the Method of Mechanical Drawing with Synchronous Ultraviolet Polymerization

“…Because of this property of band reflection, called photonic band gap effect, [ 18,19 ] CLCs have been widely applied in many optical fields, such as tunable optical bandpass filters [ 20 ] and photodetectors. [ 21 ]…”