Saturated evanescent-wave absorption of few-layer graphene-covered side-polished single-mode fiber for all-optical switching

Abstract

Using the evanescent-wave saturation effect of hydrogen-free low-temperature synthesized few-layer graphene covered on the cladding region of a side-polished single-mode fiber, a blue pump/infrared probe-based all-optical switch is demonstrated with specific wavelength-dependent probe modulation efficiency. Under the illumination of a blue laser diode at 405 nm, the fewlayer graphene exhibits cross-gain modulation at different wavelengths covering the C-and L-bands. At a probe power of 0.5 mW, the L-band switching throughput power variant of 16 μW results in a probe modulation depth of 3.2%. Blue shifting the probe wavelength from 1580 to 1520 nm further enlarges the switching throughput power variant to 24 mW and enhances the probe modulation depth to 5%. Enlarging the probe power from 0.5 to 1 mW further enlarges the switching throughput power variant from 25 to 58 μW to promote its probe modulation depth of up to 5.8% at 1520 nm. In contrast, the probe modulation depth degrades from 5.1% to 1.2% as the pumping power reduces from 85 to 24 mW, which is attributed to the saturable absorption of the few-layer graphene-based evanescent-wave absorber. The modulation depth at wavelength of 1550 nm under a probe power of 1 mW increases from 1.2% to 5.1%, as more carriers can be excited when increasing the blue laser power from 24 to 85 mW, whereas it decreases from 5.1% to 3.3% by increasing the input probe power from 1 to 2 mW to show an easier saturated condition at longer wavelength.

Broadband Nonlinear Photoresponse of 2D TiS2 for Ultrashort Pulse Generation and All‐Optical Thresholding Devices

“…2D nanomaterials have been attracting considerable interest in the field of ultrafast photonics owing to their remarkable mechanical, electronic, and optical properties, as well as their potentials in optoelectronic devices . Since graphene was found to possess ultrafast carrier dynamics and high third‐order nonlinear susceptibility, it has been widely used in photonic devices including saturable absorbers (SAs), optical modulators, photodetectors, and optical switches . The outstanding performance of graphene has motivated studies on several other types of graphene‐like 2D materials such as topological insulators (TI), transition metal dichalcogenides (TMDs) and black phosphorous (BP) in ultrafast photonics .…”

Preparation of High Damage Threshold Device Based on Bi2Se3 Film and Its Application in Fiber Lasers

“…Generally, we expect that 2D materials have a strong saturation absorption effect that would be conducive to achieving the output of ultrashort pulses. In recent years, researchers have used graphene, , black phosphorus, transition metal oxide, , topological insulator (TI), , and other thin film materials as SA, − then they observed the output phenomenon of femtosecond pulse laser in the near-infrared and mid-infrared bands. Although 2D materials have their own unique advantages, there are inevitably short plates, which means that it is difficult for us to define a design where all parameters tend to be perfect.…”

Optimization of Graphene on D-Fiber Saturable Absorbers

“…When graphene is integrated into D-fibers, the absorption can be designed to be highly dependent on the polarization, potentially resulting in broadband, large polarization extinction ratio polarizers [11]- [14]. Additionally, the absorption can be varied electrically to develop optical switches and modulators [8] and lasers with electrically controlled operation regime (continuous wave, Q-switching, or mode-locking) [10], or it can be controlled optically, to produce all-optical switches [9], [15] and saturable absorbers [10], [11], [16]- [20]. In particular, this type of saturable absorber is a very efficient passive modelocker for fiber lasers, resulting in lasers that emit very short light pulses [11].…”