Waveguide Integrated CVD Graphene Photo-Thermo-Electric Detector With &gt;40GHz Bandwidth

Marconi, Simone; Mišeikis, Vaidotas; Giambra, Marco Angelo; Montanaro, Alberto; Sorianello, Vito; Torres, Bruno Bassi Millan; Goykhman, Ilya; Coletti, Camilla; Ferrari, Andrea C.; Romagnoli, M.

doi:10.1364/cleo_si.2019.sth4n.2

Cited by 4 publications

(3 citation statements)

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“…d. Optical to electrical bandwidth of the received signal: black curve is the measurement as acquired from the VNA, blue dots are the measured response as obtained by the heterodyne setup with laser beating, the red dashed line is the interpolation curve.The spectra are completely flat in the range of frequencies of the input electrical signal as generated at the transmitter side without any ripples or a drop at high frequencies. This demonstrates the high speed of operation of our detectors, as already demonstrated for a similar device in our previous work where we showed flat response up to 40GHz52 . The response shown inFig 6c.is flat up to 45 GHz, beyond this we see a 10 dB drop of the power at signals Nyquist frequency.…”

supporting

confidence: 86%

Silicon Photonics: a Scaling Technology for Communications and Interconnects

Dong

Kim

Melikyan

et al. 2018

2018 IEEE International Electron Devices Meeting (IEDM)

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The challenge of next generation datacom and telecom communication is to increase the available bandwidth while reducing the size, cost and power consumption of photonic integrated circuits 1,2 . Silicon (Si) photonics has emerged as a viable solution to reach these objectives 3,4 . Graphene, a single-atom thick layer of carbon 5 , has been recently proposed to be integrated with Si photonics because of its very high mobility 6 , fast carrier dynamics 7 and ultra-broadband optical properties 8 . Here, we focus on graphene photodetectors for high speed datacom and telecom applications. High speed graphene photodetectors have been demonstrated so far 9 , however the most are based on the photo-bolometric (PB) 10-12 or photo-conductive (PC) 13,14 effect. These devices are characterized by large dark current, in the order of milli-Amperes , which is an impairment in photo-receivers design 15 , Photothermo-electric (PTE) effect has been identified as an alternative phenomenon for light detection 16 . The main advantages of PTE-based photodetectors are the optical power to voltage conversion, zero-bias operation and ultrafast response 17 . Graphene PTE-based photodetectors have been reported in literature [18][19][20][21][22] , however high-speed optical signal detection has not been shown. Here, we report on an optimized graphene PTE-based photodetector thermoelectric effect (Seebeck effect) which is proportional to the spatial gradient of the HC's temperature [49][50][51] .The generated photovoltage does not require an externally applied bias, allowing zero dark current operation and direct voltage generation 48 . These properties are very appealing in terms of noise and power consumption, as PTE allows direct connection between the graphene photodetector and the read-out electronics without TIAs 17 .Waveguide integrated graphene detectors based on PTE effect have been reported in recent years showing voltage responsivity in the range 3.5 V W -1 -28 V W -1 18-22 . These devices are based on the enhancement of the gradient of HC's temperature through the improvement of the optical absorption by means of photonic structures confining the optical field in ~100nm gaps 18,19,22 or by exploiting the resonance of a microring resonator 20 . Despite the remarkable voltage responsivity 20,22 , detection of an optical data transmission using PTE-based graphene photodetectors operating in unbiased condition has not been demonstrated yet. The optimization of the photovoltage signal in a PTE detector requires to set the detector at an operating condition near the Charge Neutrality Point (CNP), i.e. where the conductivity of graphene is lowest. For this reason, typical PTE photodetectors exhibit output resistance from several hundreds to thousands of Ohms 18-22 , i.e. too high for proper matching to the typical 50 Ω impedance of the test instruments.Here we report on a PTE graphene photodetector integrated on a Si photonic waveguide having a voltage responsivity of about 3.5 V W -1 and a frequency response flat up to 65 GHz showin...

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confidence: 86%

Silicon Photonics: a Scaling Technology for Communications and Interconnects

Dong

Kim

Melikyan

et al. 2018

2018 IEEE International Electron Devices Meeting (IEDM)

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“…On the other hand, most of the reported graphene photodetectors have a responsivity of less than 100 mA/W 20,23,[27][28][29][30][31][33][34][35] when operating at a low bias voltage, e.g., |V b |<0.3 V. As it is well known, for the metal-graphene-metal (MGM) photodetectors, the responsivity is usually in positive correlation to the bias-voltage V b [20][21][22][23]25,[27][28][29][30][31][32]37,38,45,50 and in negative correlation to the input optical power P in 21,22,37,38 . Meanwhile, it is usually desired to be able to detect low optical power under a low bias voltage because a low bias voltage operation helps to reduce the dark currents and suppress the shot noise.…”

Section: Discussion and Outlooksmentioning

confidence: 99%

“…However, the responsivity performance of these high-speed graphene waveguide photodetectors still needs improvements when the low bias voltages are applied in case of large dark currents. For example, the graphene waveguide photodetectors utilizing the photovoltaic (PV) effect [23][24][25][26][27][28][29] , the photo-thermoelectric (PTE) effect [30][31][32][33][34] , or the internal photoemission effect (IPE) 35 usually have limited responsivities (<78 mA/W at zero bias 30 , and <170 mA/W @ <0.4 V 32 ).…”

Section: Introductionmentioning

confidence: 99%

High-performance silicon−graphene hybrid plasmonic waveguide photodetectors beyond 1.55 μm

et al. 2020

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A fast silicon-graphene hybrid plasmonic waveguide photodetectors beyond 1.55 μm is proposed and realized by introducing an ultra-thin wide silicon-on-insulator ridge core region with a narrow metal cap. With this novel design, the light absorption in graphene is enhanced while the metal absorption loss is reduced simultaneously, which helps greatly improve the responsivity as well as shorten the absorption region for achieving fast responses. Furthermore, metal-graphenemetal sandwiched electrodes are introduced to reduce the metal-graphene contact resistance, which is also helpful for improving the response speed. When the photodetector operates at 2 μm, the measured 3dB-bandwidth is >20 GHz (which is limited by the experimental setup) while the 3dB-bandwith calculated from the equivalent circuit with the parameters extracted from the measured S 11 is as high as ~100 GHz. To the best of our knowledge, it is the first time to report the waveguide photodetector at 2 μm with a 3dB-bandwidth over 20 GHz. Besides, the present photodetectors also work very well at 1.55 μm. The measured responsivity is about 0.4 A/W under a bias voltage of −0.3 V for an optical power of 0.16 mW, while the measured 3dB-bandwidth is over 40 GHz (limited by the test setup) and the 3 dB-bandwidth estimated from the equivalent circuit is also as high as ~100 GHz, which is one of the best results reported for silicon-graphene photodetectors at 1.55 μm.

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Photo thermal effect graphene detector featuring 105 Gbit s−1 NRZ and 120 Gbit s−1 PAM4 direct detection

et al. 2021

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One of the main challenges of next generation optical communication is to increase the available bandwidth while reducing the size, cost and power consumption of photonic integrated circuits. Graphene has been recently proposed to be integrated with silicon photonics to meet these goals because of its high mobility, fast carrier dynamics and ultra-broadband optical properties. We focus on graphene photodetectors for high speed datacom and telecom applications based on the photo-thermo-electric effect, allowing for direct optical power to voltage conversion, zero dark current, and ultra-fast operation. We report on a chemical vapour deposition graphene photodetector based on the photo-thermoelectric effect, integrated on a silicon waveguide, providing frequency response >65 GHz and optimized to be interfaced to a 50 Ω voltage amplifier for direct voltage amplification. We demonstrate a system test leading to direct detection of 105 Gbit s−1 non-return to zero and 120 Gbit s−1 4-level pulse amplitude modulation optical signals.

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Waveguide Integrated CVD Graphene Photo-Thermo-Electric Detector With >40GHz Bandwidth

Cited by 4 publications

References 3 publications

Silicon Photonics: a Scaling Technology for Communications and Interconnects

Silicon Photonics: a Scaling Technology for Communications and Interconnects

High-performance silicon−graphene hybrid plasmonic waveguide photodetectors beyond 1.55 μm

Photo thermal effect graphene detector featuring 105 Gbit s−1 NRZ and 120 Gbit s−1 PAM4 direct detection

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