Coupling-enhanced dual ITO layer electro-absorption modulator in silicon photonics

Tahersima, Mohammad H.; Ma, Zhizhen; Gui, Yaliang; Sun, Shikun; Wang, Hao; Amin, Rubab; Dalir, Hamed; Chen, Ray; Miscuglio, Mario; Sorger, Volker J.

doi:10.1515/nanoph-2019-0153

Cited by 53 publications

(26 citation statements)

References 57 publications

(100 reference statements)

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“…In epitaxial CdO grown on sapphire, the effect is prominent up to carrier densities of 3.3 × 10 20 cm −3 , as shown in previous studies . We deposited our CdO films on fused silica substrates keeping in mind practical device‐applications where the films are usually deposited on an oxide (SiO 2 , Al 2 O 3 , or HfO 2 ) or on silicon . This led to the growth of polycrystalline CdO films (Figure S1.2, Supporting Information), which increased the Drude‐damping caused by scattering across grain boundaries, compared to epitaxial layers grown on sapphire or magnesium oxide .…”

Section: Resultsmentioning

confidence: 69%

Broadband, High‐Speed, and Large‐Amplitude Dynamic Optical Switching with Yttrium‐Doped Cadmium Oxide

Saha

Diroll

Shank

et al. 2019

Adv Funct Materials

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Transparent conducting oxides, such as doped indium oxide, zinc oxide, and cadmium oxide (CdO), have recently attracted attention as tailorable materials for applications in nanophotonic and plasmonic devices such as low‐loss modulators and all‐optical switches due to their tunable optical properties, fast optical response, and low losses. In this work, optically induced extraordinarily large reflection changes (up to 135%) are demonstrated in bulk CdO films in the mid‐infrared wavelength range close to the epsilon near zero (ENZ) point. To develop a better understanding of how doping level affects the static and dynamic optical properties of CdO, the evolution of the optical properties with yttrium (Y) doping is investigated. An increase in the metallicity and a blueshift of the ENZ point with increasing Y‐concentrations is observed. Broadband all‐optical switching from near‐infrared to mid‐infrared wavelengths is demonstrated. The major photoexcited carrier relaxation mechanisms in CdO are identified and it is shown that the relaxation times can be significantly reduced by increasing the dopant concentration in the film. This work could pave the way to practical dynamic and passive optical and plasmonic devices with doped CdO spanning wavelengths from the ultraviolet to the mid‐infrared region.

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Section: Resultsmentioning

confidence: 69%

Broadband, High‐Speed, and Large‐Amplitude Dynamic Optical Switching with Yttrium‐Doped Cadmium Oxide

Saha

Diroll

Shank

et al. 2019

Adv Funct Materials

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“…channel crosstalk (Figure 3f). Physically this range corresponds to a small (ΔT = 0.54 K) temperature change that the waveguide index must tolerate to keep within the selected attenuation [21][22][23] or electro-absorption modulators [19,20], and also to <10 μm-short 2 × 2 directional couplers [56] allowing for improved N-scaling of OFFT-based convolutions. GPU processing times obtained by fitting runtime.…”

Section: Resultsmentioning

confidence: 99%

“…In the latter a digitalto-analog converter (DAC) may be needed front-end, and an ADC back-end. Next, the dot-product multiplication to be performed as part of core of the tensor processor can be achieved in a multitude of options such as via electro-optic weighting by controlling the amplitude such as via an electro-absorption modulator [19,20], and phase-shifter using an Mach Zehnder interferometer (MZI) [16,[21][22][23], or via photonic nonvolatile memory such as enabled by phasechange-material weighted states [24], or all-optically [25]. Each of these options can be performed non-resonantly (i.e.…”

Section: Introductionmentioning

confidence: 99%

Integrated photonic FFT for photonic tensor operations towards efficient and high-speed neural networks

et al. 2020

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AbstractThe technologically-relevant task of feature extraction from data performed in deep-learning systems is routinely accomplished as repeated fast Fourier transforms (FFT) electronically in prevalent domain-specific architectures such as in graphics processing units (GPU). However, electronics systems are limited with respect to power dissipation and delay, due to wire-charging challenges related to interconnect capacitance. Here we present a silicon photonics-based architecture for convolutional neural networks that harnesses the phase property of light to perform FFTs efficiently by executing the convolution as a multiplication in the Fourier-domain. The algorithmic executing time is determined by the time-of-flight of the signal through this photonic reconfigurable passive FFT ‘filter’ circuit and is on the order of 10’s of picosecond short. A sensitivity analysis shows that this optical processor must be thermally phase stabilized corresponding to a few degrees. Furthermore, we find that for a small sample number, the obtainable number of convolutions per {time, power, and chip area) outperforms GPUs by about two orders of magnitude. Lastly, we show that, conceptually, the optical FFT and convolution-processing performance is indeed directly linked to optoelectronic device-level, and improvements in plasmonics, metamaterials or nanophotonics are fueling next generation densely interconnected intelligent photonic circuits with relevance for edge-computing 5G networks by processing tensor operations optically.

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“…Our material property findings for ITO in this study are indeed far-ranging beyond photoabsorption, but can further be used to electro-optic devices as well [53][54][55][56]. For instance, the optical index can be tuned electrostatically via chancing the free carrier concentration leading to electro-optic modulators, both for electro-absorption [57][58][59], but also used in interferometric schemes [60][61][62] to demonstrate high-performance…”

Section: Impact Of Thickness Of Ito Window Layer In the Performance Cmentioning

confidence: 95%

Structure, Electrical and Optical Properties of ITO Thin Films and Their influence on Performance of CdS/CdTe Thin-Film Solar Cells

Ahmed

Bakry

Shaaban

et al. 2021

Preprint

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ITO was prepared by mixing gradient In2O3 and SnO2 powders using solid phase reaction manner. Using electron beam gun tool, ITO films with varied thicknesses were fabricated. The structure, electrical and optical parameters of the prepared films were studied. XRD patterns were used to establish the micro-structural parameters (lattice strain and crystallite size). The SEM shows improvement of grain size with the increase of the film thickness. The electrical parameters of ITO films were measured by means of the standard four-point probe method. It was found that when the film thickness increases from 75 nm to 375 nm, the resistivity decreases to lower value of 1.65×10-4 Ω.cm and slightly increases to 1.93 ×10-4 Ω.cm at thickness of 375 nm. The ITO films with lower electrical properties are appropriate for high-efficiency CdTe solar cells. In terms of spectral ellipsomeric, three optical layer models (adhesive layer of the substrate/B-spline layer of ITO film/surface roughness layer) were applied to estimate the film thickness with high accuracy. The absorption coefficient and energy gap were calculated from the transmission and reflection spectra in the strong absorption region. As the film thickness increases, the optical energy gap was found to increase from 3.56 eV to 3.69 eV. In terms of Hall-effect measurements, both carrier concentration and hall mobility were determined. In addition, influences of ITO layers with various thicknesses on the performance of CdS/CdTe solar cells were checked. When the ITO window layer thickness is 325 nm, Jsc = 17 mA/cm2, Voc = 0.82 V, and FF = 57.4%, the calculated highest power conversion efficiency (PCE) is 8.6%.

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Coupling-enhanced dual ITO layer electro-absorption modulator in silicon photonics

Cited by 53 publications

References 57 publications

Broadband, High‐Speed, and Large‐Amplitude Dynamic Optical Switching with Yttrium‐Doped Cadmium Oxide

Broadband, High‐Speed, and Large‐Amplitude Dynamic Optical Switching with Yttrium‐Doped Cadmium Oxide

Integrated photonic FFT for photonic tensor operations towards efficient and high-speed neural networks

Structure, Electrical and Optical Properties of ITO Thin Films and Their influence on Performance of CdS/CdTe Thin-Film Solar Cells

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