Novel approach for the integration of photonic circuits with mid-IR detectors (original) (raw)
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Extrinsic photodiodes for integrated mid-infrared silicon photonics
Optica, 2014
Silicon photonics has recently been proposed for a diverse set of applications at mid-infrared wavelengths 1, 2 , the implementation of which require on-chip photodetectors. In planar geometries, dopant-based extrinsic photoconductors have long been used for mid-infrared detection with Si and Ge acting as host materials 3. Leveraging the dopant-induced sub-bandgap trap-states used in bulk photoconductors for waveguide integrated mid-infrared detectors offers simple processing, integration, and operation throughout the mid-infrared by appropriate choice of dopant (Fig. 1a). In particular, Si doped with Zn forms two trap levels ≈ 0.3 eV and ≈ 0.58 eV above the valence band 4-6 , and has been utilized extensively for cryogenically cooled bulk extrinsic photoconductors 3, 7. In this letter, we present room temperature operation of Zn + implanted Si waveguide photodiodes (Figs. 1b,c) from 2.2 µm to 2.4 µm, with measured responsivities of up to 87 ± 29 mA/W and low dark currents of < 10μA. While a number of Si waveguide (SiWG) integrated optoelectronic devices have been demonstrated in this wavelength range 8, 9 , efficient photodetection remains an important and challenging task. Thus, spectral translation of mid-infrared signals to the telecom regime via four-wave mixing in SiWGs has been proposed for on-chip detection 10 , which makes use of the sensitive integrated photodiodes (PDs) in the telecommunications wavelength range 11. However, this method requires a high-powered pump laser and long, on-chip-waveguide lengths to achieve efficient wavelength conversion. In addition, heterogeneous integration of both narrow-bandgap semiconductors 9,12-14 and graphene 15,16 with SiWGs has been demonstrated for on-chip mid-infrared detection. Though viable PDs have been demonstrated,
Sensors and Actuators B-Chemical, 2013
We present theory and simulation of a mid-infrared ( = 3.2 m) chalcogenide waveguide monolithically integrated with an evanescently coupled PbTe photodetector for lab-on-a-chip sensing applications. A spacer layer is used to modify effective index of the structure, enabling a waveguide-detector mode to propagate in the chalcogenide waveguide and be absorbed in the PbTe detector. The relation between quantum efficiency and detector dimensions is analyzed showing that the design geometry can be optimized to maximize signal to noise ratio. In addition, the location of metal contacts is optimized to minimize loss while maintaining good device performance. The design is compatible with standard planar lithographic processing and its flexibility suggests multiple applications in the fields of biological and chemical sensing.
Mid-IR photonic integrated circuits
2012
The Mid-IR wavelength range is particularly interesting for spectroscopic sensing applications. Integration of Quantum Cascade Lasers with a photonic integrated circuit will pave the way for providing a tunable laser source along with a possibility of Lab-on-achip applications. A major challenge in realization of these devices is identification of a suitable waveguide platform. In this paper we will discuss the design and fabrication strategies of the possible waveguide platforms and will propose a generic concept of realizing a widely tunable integrated QCL using wavelength selective feedback elements implemented on a silicon photonic chip.
Mid-infrared materials and devices on a Si platform for optical sensing
Science and Technology of Advanced Materials, 2014
In this article, we review our recent work on mid-infrared (mid-IR) photonic materials and devices fabricated on silicon for on-chip sensing applications. Pedestal waveguides based on silicon are demonstrated as broadband mid-IR sensors. Our low-loss mid-IR directional couplers demonstrated in SiN x waveguides are useful in differential sensing applications. Photonic crystal cavities and microdisk resonators based on chalcogenide glasses for high sensitivity are also demonstrated as effective mid-IR sensors. Polymer-based functionalization layers, to enhance the sensitivity and selectivity of our sensor devices, are also presented. We discuss the design of mid-IR chalcogenide waveguides integrated with polycrystalline PbTe detectors on a monolithic silicon platform for optical sensing, wherein the use of a low-index spacer layer enables the evanescent coupling of mid-IR light from the waveguides to the detector. Finally, we show the successful fabrication processing of our first prototype mid-IR waveguide-integrated detectors.
2018
A compact and cheap mid-infrared spectrometer is realized by integrating a Silicon-on-Insulator (SOI) Arrayed Waveguide Grating (AWG) spectrometer operating in the 2.3 μm wavelength range with a high performance photodiode. The AWG has twelve output channels with a spacing of 225 GHz (4 nm) and a free spectral range (FSR) of 3150 GHz (56 nm), which are simultaneously collected by a single, transistor outline (TO)-packaged extended InGaAs PIN photodiode. The response of each AWG channel is discerned by time-sequentially modulating the optical power in each output channel using integrated Mach-Zehnder based (MZI) thermo-optic modulators with a π-phase shift power consumption of 50 mW. The photonic chip is interfaced using off-the-shelf electronic components and a standard 9/125 single-mode fiber. The response of the AWG is limited to one FSR using a 50 nm Full Width Half-Maximum (FWHM) bandpass interference filter. Using 31 μW optical power in the fiber, the absorption spectrum of a 0...
Sensitivity Comparison of Integrated Mid-Infrared Silicon-Based Photonic Detectors
Proceedings, 2018
Integrated silicon photonics in the mid-infrared is a promising platform for cheap and miniaturized chemical sensors, including gas and/or liquid sensors for environmental monitoring and the consumer electronics market. One major challenge in integrated photonics is the design of an integrated detector sensitive enough to detect minimal changes in light intensity resulting from, for example, the absorption by the analyte. Further complexity arises from the need to fabricate such detectors at a high throughput with high requirements on fabrication tolerances. Here we analyze and compare the sensitivity of three different chip-integrated detectors at a wavelength of 4.17 µm, namely a resistance temperature detector (RTD), a diode and a vertical-cavity enhanced resonant detector (VERD).
Mid-infrared integrated photonics on a SiGe platform
2015 Opto-Electronics and Communications Conference (OECC), 2015
The mid-infrared is of great interest for a huge range of applications such as medical and environment sensors, security, defense and astronomy. I will give a broad overview of the different activities recently launched in INL Lyon, in close collaboration with several French and Australian institutions, under the umbrella of "Mid-IR integrated photonics" with a particular focus on novel integrated sources for the Mid-IR exploiting a nonlinear SiGe platform
Integrated Silicon-on-Insulator Spectrometer With Single Pixel Readout for Mid-Infrared Spectroscopy
IEEE Journal of Selected Topics in Quantum Electronics
Mid-infrared spectroscopy in the 2-4 µm wavelength range is of cardinal value for many sensing applications. Current solutions involve bulky and expensive systems to operate. Silicon-on-Insulator (SOI) waveguide technology offers means to miniaturize the different parts of the spectrometer. However, the development of on-chip detectors for the mid-infrared wavelength range is in its infancy and the characteristics are not on par with their discrete (cooled) counterparts. In this work, a compact and cheap mid-infrared spectrometer is realized by integrating a SOI Arrayed Waveguide Grating (AWG) spectrometer operating in the 2.3 µm wavelength range with a high performance midinfrared photodiode. The AWG has twelve output channels with a spacing of 225 GHz (4 nm) and a free spectral range (FSR) of 3150 GHz (56 nm), which are simultaneously collected by a single, transistor outline (TO)-packaged extended InGaAs PIN photodiode. The response of each AWG channel is discerned by time-sequentially modulating the optical power in each output channel using integrated Mach-Zehnder based (MZI) thermooptic modulators with a π-phase shift power consumption of ≈ 50 mW. As an example, the absorption spectrum of a 0.5 mm thick polydimethylsiloxane sheet (PDMS) is sampled and compared to a benchtop spectrometer to good agreement.