Single rolled-up InGaAs/GaAs quantum dot microtubes integrated with silicon-on-insulator waveguides

Abstract

We report on single rolled-up microtubes integrated with silicon-on-insulator waveguides. Microtubes with diameters of ~7 μm, wall thicknesses of ~250 nm, and lengths greater than 100 μm are fabricated by selectively releasing a coherently strained InGaAs/GaAs quantum dot layer from the handling GaAs substrate. The microtubes are then transferred from their host substrate to silicon-on-insulator waveguides by an optical fiber abrupt taper. The Q-factor of the waveguide coupled microtube is measured to be 1.5×10(5), the highest recorded for a semiconductor microtube cavity to date. The insertion loss and extinction ratio of the microtube are 1 dB and 34 dB respectively. By pumping the microtube with a 635 nm laser, the resonance wavelength is shifted by 0.7 nm. The integration of InGaAs/GaAs microtubes with silicon-on-insulator waveguides provides a simple, low loss, high extinction passive filter solution in the C+L band communication regime.

Whispering-gallery modes of μ-optic silicon bottle resonator examined using a Fourier–Bessel eigen-state approach

“…The hollow internal region provides an access port for fluid flow 33,34 and for mechanical positioning. 35 The Gaussian shape bottle resonator region is retained in the analysis and the presence of an inner radius equal to 1.75 μm completely removes the supporting cylindrical region. Figure 10 is produced by modifying the dielectric profile, recomputing the inverse dielectric expansion coefficients and then computing the eigenvalues for the fundamental mode of azimuthal order 22.…”

Counterpropagating Whispering-Gallery-Modes of Rolled-up Semiconductor Microtubes

“…A novel microtube directional coupler has also been proposed [8]. Recently, we reported on approaches to evanescently couple light into microtubes either using an optical fiber adiabatic taper [9] or integrated with a silicon-on-insulator waveguide [10]. Through these passive coupling experiments, the transmission spectra of microtubes have been demonstrated at telecom wavelengths.…”

Curvature effects on valley splitting and degeneracy lifting: Case of Si/Ge rolled-up nanotubes

“…[9][10][11][12][13][14][15] In particular, rolled-up nanotubes, originating from the self-scrolling of a differentially stressed film when released from a substrate, have recently proven to be particularly promising for the design of new functional devices. 12,13,[16][17][18][19][20][21] With the aim of engineering the electronic properties of the tubes, a preliminary theoretical study is of the uttermost importance. To the best of our knowledge, only recently a few theoretical studies of the electronic properties of rolled-up tubes have appeared, 7,22-25 but they all use a continuum approach (k · p with effective mass), while a complete atomistic calculation of the electronic band structure over the whole Brillouin Zone (BZ) capturing all the relevant features is still lacking.…”