All-optical signal processing at ultra-low powers in bottle microresonators using the Kerr effect

Abstract

We present experimental results on nonlinear, ultra-low power photonics applications based on a silica whispering-gallery-mode microresonator. Our bottle microresonator combines an ultrahigh quality factor of Q > 10(8) with a small mode volume V. The resulting Q(2)/V-ratio is among the highest realized for optical microresonators and allows us to observe bistable behavior at very low powers. We report single-wavelength all-optical switching via the Kerr effect at a record-low threshold of 50 microW. Moreover, an advantageous mode geometry enables the coupling of two tapered fiber waveguides to a bottle mode in an add-drop configuration. This allows us to route a CW optical signal between both fiber outputs with high efficiency by varying its power level. Finally, we demonstrate that the same set-up can also be operated as an optical memory.

Metawaveguide for Asymmetric Interferometric Light-Light Switching

“…Here, a relatively small value of δ ¼ 2 was chosen to obtain a reasonable transmission efficiency and ensure that fabrication imperfections do not make the system deviate strongly from the designed CPA condition. We find that the intensity ratio ξ is given by ðδ þ 1Þ=ðδ − 1Þ, leading to ξ of 3∶1 between the strong signal beam and the weak control beam [33], which is in contrast to the previous approaches of controlling light with light using both linear and nonlinear strategies [1][2][3][4][5][6][7][8][9][10][11][12][13][14].…”

“…DOI: 10.1103/PhysRevLett.117.193901 Effective light-light switching promises optical information processing, which has been a long-standing driving force for high-speed and energy-efficient optical networks. Strong optical modulations are initiated in nonlinear optical media by intense laser fields to enable switching of a weak signal, for example, intensity modulation of light by light has been demonstrated based on the all-optical Kerr effect [1][2][3][4][5][6]. Nevertheless, the high power requirement for the intense control or pump light becomes a significant barrier for practical applications.…”

Kerr nonlinear switching in a hybrid silica-silicon microspherical resonator

“…Of these fiber resonators, much focus has been placed on devices that are fashioned from the extremely low loss silica platforms so that Q factors above 10 7 can be readily achieved [7,9]. Thus, despite silica's relatively modest nonlinear coefficients, these ultra-high-Q resonators have still found use for nonlinear applications including all-optical switching [10,11] and third harmonic generation [12].…”

Light-controlled microwave whispering-gallery-mode quasi-optical resonators at 50W LED array illumination

“…Major progress is achieved in optics where Q factors exceeding one billion 2 are demonstrated and huge enhancement to other characteristics of devices are realized. The devices include biological and chemical sensors of nanoparticles and bio-molecules, 3,4 unique ultralow-threshold lasers, 5 advanced opto-electronic and electro-optical switchers and oscillators, [6][7][8] etc.…”