Low-loss silicon nitride waveguide hybridly integrated with colloidal quantum dots

Abstract

Silicon nitride waveguides with a monolayer of colloidal quantum dots embedded inside were fabricated using a low-temperature deposition process and an optimized dry etching step for the composite layers. We experimentally demonstrated the luminescence of the embedded quantum dots is preserved and the loss of these hybrid waveguide wires is as low as 2.69dB/cm at 900nm wavelength. This hybrid integration of low loss silicon nitride photonics with active emitters offers opportunities for optical sources operating over a very broad wavelength range. References and links1. E. S. Hosseini, S. Yegnanarayanan, A. H. Atabaki, M. Soltani, and A. Adibi, "High quality planar silicon nitride microdisk resonators for integrated photonics in the visible wavelength range," Opt.

Sideband pump-probe technique resolves nonlinear modulation response of PbS/CdS quantum dots on a silicon nitride waveguide

“…48 To enhance the modulation depth reached in photonic devices, the QDs or nanoplatelets can be implanted into the silicon nitride waveguide, as has been demonstrated in Ref. 36. The sideband pump-probe method we developed proved to be a suitable tool for the quantitative measurement of small changes in the imaginary and real parts of the refractive index.…”

“…[30][31][32] Additionally, a range of hybrid photonic devices based on silicon nitride structures has been demonstrated. 10,[33][34][35][36][37] In contrast to pure silicon, the material does not display large intrinsic nonlinearities or a substantial free carrier absorption 38 and therefore allows us to observe the nonlinear response of the QDs without waveguide-induced background. A schematic of the sample is displayed in Fig.…”

“…Exploiting the fact that pump and probe pulses are coerced to propagate colinearly in a waveguide, the heterodyne detected pump-probe approach can yield an enhanced signal-to-noise ratio compared to a spatial pulse overlap only in the focal spot, as the signal is accumulated over the whole pump and probe propagation length. For low-loss waveguides, like the silicon nitride waveguides we employ, 36 the propagation length can reach macroscopic distances, as is exemplified in Fig. 3(a), where we show a top image of a blank silicon nitride waveguide with in-and outcoupling spots of our pilot laser.…”

“…For applications, the mode overlap with the active region can be increased by using a material with larger refractive index contrast for a better mode confinement or by imbedding the QDs into the waveguide. 36 In this case, the overlap will be increased to about 19% and could be increased further by stacking multiple layers of QDs or using a higher refractive index material in the waveguides. With only a factor of two difference to this rather advanced approach, the spin-coating of samples onto a waveguide can be reasonably put forward as the technique of choice for serial testing and characterization experiments.…”

Silicon and silicon nitride photonic circuits for spectroscopic sensing on-a-chip [Invited]

“…In addition, to enable effective coupling between the emission and the optical modes, more specifically in optical cavities, the light field in the Si 3 N 4 components should maximally overlap with the QD emitters. In our study, we have developed a fully inorganic and low-loss Si 3 N 4 -QD hybrid photonic platform by using a low-temperature (120°C-270°C) plasma enhanced chemical vapor deposition process and an optimized dry etching step, and demonstrated loss as low as 2.7 dB∕cm at 900 nm wavelength for waveguides with embedded QDs [49]. [50].…”