All-optical control of microfiber resonator by graphene's photothermal effect

Abstract

We demonstrate an efficient all-optical control of microfiber resonator assisted by graphene's photothermal effect. Wrapping graphene onto a microfiber resonator, the light-graphene interaction can be strongly enhanced via the resonantly circulating light, which enables a significant modulation of the resonance with a resonant wavelength shift rate of 71 pm/mW when pumped by a 1540 nm laser. The optically controlled resonator enables the implementation of low threshold optical bistability and switching with an extinction ratio exceeding 13 dB. The thin and compact structure promises a fast response speed of the control, with a rise (fall) time of 294.7 μs (212.2 μs) following the 10%–90% rule. The proposed device, with the advantages of compact structure, all-optical control, and low power acquirement, offers great potential in the miniaturization of active in-fiber photonic devices.

2D Materials for Optical Modulation: Challenges and Opportunities

“…This efficient phase shift can offer a total shutting off of the signal light. A prominent photothermal effect has also been reported in a graphene‐clad microfiber ring resonator, which enabled a low threshold optical bistability and switching . However, limited by the thermo inertia, the response time is on the order of microseconds.…”

Graphene filled optical fiber Fabry‐Pérot cavity tunable filter

“…In the infrared to visible spectral range, the monolayer graphene exhibits an optical sheet conductivity value of πe 2 /2 h (where e is the electron charge, and h is plank constant) and a frequency independent constant optical absorption coefficient of πe 2 /ℏ c = 2.293% (where ℏ is h /2π, and c is the speed of light) . Moreover, the optical absorption coefficient increases linearly with the increase of graphene layers . The photocarrier generation is driven by optical absorption, which is governed by the averaged light intensity .…”

“…4 Moreover, the optical absorption coefficient increases linearly with the increase of graphene layers. 3,[5][6][7] The photocarrier generation is driven by optical absorption, which is governed by the averaged light intensity. [8][9][10] Photocarriers change can be reflected in the photoinduced refractive index, photoinduced absorption coefficient, and photoinduced conductivity of the graphene.…”

A Microfiber Knot Incorporating a Tungsten Disulfide Saturable Absorber Based Multi-Wavelength Mode-Locked Erbium-Doped Fiber Laser

“…Since the first microfiber cavity laser was demonstrated [25], optical devices based on microfibers have played a major role in many domains including light detection, communications and sensing due to low cost and ease of preparation [25,26]. Researchers have developed several resonators based on microfiber, such as the loop resonator [27,28], knot resonator [29][30][31][32][33][34][35][36][37] and coil resonator [38,39]. Among the resonators based on a microfiber, the knot resonator has the recognized advantages of ease of fabrication, simple structure, and compact size [29][30][31][32].…”

“…Additionally, it is possible that the microfiber knot has a significant role to play in conjunction with other optical materials due to the effective photon interaction resulting from the strong evanescent amplification of the microfiber knot geometry [41]. A hybrid structure comprising a microfiber knot resonator combined with graphene has been demonstrated by coating the microfiber knot with graphene [32]. The resulting excellent characteristics include high optical non-linearity and rapid response time, which confirm the possibility that a new device based on the microfiber knot can be highly applicable for non-linear optical device, high performance optical fiber sensors, ultrafast modulators etc.…”