A direct comparison of single-walled carbon nanotubes and quantum-wells based subpicosecond saturable absorbers for all optical signal regeneration at 1.55 μm

Abstract

Subpicosecond optical transmission experiments are used to compare saturable absorber ͑SA͒ based on bundled single-walled carbon nanotubes ͑SWNT͒ and iron-doped InGaAs/InP epitaxial multiple quantum wells ͑MQW͒ at 1.55 m telecom wavelength. The SA key parameters ͑contrast ratio, saturation fluence, and recovery time͒ relevant for high speed all optical signal regeneration ͑AOSR͒ are extracted from the normalized differential transmission ͑NDT͒. Although both SA exhibit good contrast ratios, SWNT show a full signal recovery as well as a much faster response time than MQW. This original work on SA shows that SWNT are excellent candidates for future low cost AOSR.

Photonics based on carbon nanotubes

“…This simple process holds to obtain a dried film of SWCNT in bundles, which has already been structurally analyzed by Raman spectroscopy and scanning tunneling microscopy [11] For M-SWCNT way, 10 mg of pristine SWCNT powder was added to 20 ml of 2%-sodium-cholate water solution, then sonicated for 1 h, and finally centrifuged at 25,000× g for 1 h; the upper suspension layer was dropped on a glass substrate, leading to a few microns-thick SWCNT film. We already reported the linear absorption spectra of both samples in [10], which indicate that the SWCNT first excitonic transition energies are suitable for 1,550-nm-window photonics applications.…”

“…We first directly compare SWCNT with MQW absorption nonlinearities, aiming at demonstrating the huge potential of SWCNT-based optical devices for saturable absorption applications as an easier-process and lower-cost efficient solution than conventional semiconductor MQW [10,11]. This work highlights the interest for future photonics to benefit from larger one-dimensional (1D) excitonic nonlinearities in SWCNT than 2D in MQW.…”

Chirality distribution in single walled carbon nanotube films by spectroscopic ellipsometry

“…SWCNTs are considered as promising candidates for future optical and electronic devices such as field effect transistor, 1 gas sensors, 2,3 optical bolometer, 4 laser source, 5 and saturable absorber. 6 However, as shown previously, 3 the performances of these devices can be drastically affected by the chirality distribution.…”

“…Films of CoMoCat SWCNTs and SWCNTs enriched in (6,5) chirality are considered. Classical methods like photoluminescence spectroscopy frequently give incomplete distribution.…”

“…By comparing the S 11 and S 22 transition energy to the tabulated one (Fig. 3), 18 semiconducting SWCNTs are assigned to (6,5), (7,5), (7,6), (8,3), (8,4), (8,6), (8,7), (9,7), and (9,8) SWCNTs. These films contain nearly armchair SWCNTs.…”