SWNT Saturable Absorption Application in Telecom Wavelength Range

The current study investigated saturable absorption of a single-wall carbon nanotube (SWNT) layer in the optical spectral range. Initially, a glass substrate was covered with an SWNT layer several μm in width to determine its attenuation properties in the optical telecom spectrum. The spectral response of the broadband source was 1260 to 1640 nm, linear and non-gradient. Attenuation behavior in the narrow spectrum sources depended on optical power variation. Saturation absorption occurred at the peak of optical power. This characteristic was observed for laser diodes with wavelengths of 1310 and 1550 nm. The EDFA optical amplifier showed saturable absorption. This property can be applied to increase side mode suppression ratio 7 dB in laser diodes and improve optical signal-to-noise ratio 8 dB in optical amplifiers.