Photonic integrated spiking neuron chip based on a self-pulsating DFB laser with a saturable absorber

Yuechun Shi; Shuiying Xiang; Xingxing Guo; Yahui Zhang; Hongji Wang; Dianzhuang Zheng; Yuna Zhang; Yanan Han; Yong Zhao; Xiaojun Zhu; Xiangfei Chen; Xun Li; Yue Hao

doi:10.1364/PRJ.485941

Journals >Photonics Research >Volume 11 >Issue 8 >Page 1382 > Article

Photonics Research
Vol. 11, Issue 8, 1382 (2023)

Photonic integrated spiking neuron chip based on a self-pulsating DFB laser with a saturable absorber

Yuechun Shi^1、7、†, Shuiying Xiang^2、†,*, Xingxing Guo², Yahui Zhang², Hongji Wang³, Dianzhuang Zheng^1、2, Yuna Zhang², Yanan Han², Yong Zhao⁴, Xiaojun Zhu⁵, Xiangfei Chen³, Xun Li⁶, and Yue Hao²

Author Affiliations

¹Yongjiang Laboratory, Ningbo 315202, China

²State Key Laboratory of Integrated Service Networks, State Key Discipline Laboratory of Wide Bandgap Semiconductor Technology, Xidian University, Xi’an 710071, China

³Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Institute of Optical Communication Engineering, Nanjing University, Nanjing 210023, China

⁴School of Science, Jiangnan University, Wuxi 214122, China

⁵School of Information Science and Technology, Nantong University, Nantong 226019, China

⁶Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario L8S 4K1, Canada

⁷e-mail: yuechun-shi@ylab.ac.cn

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DOI: 10.1364/PRJ.485941 Cite this Article Set citation alerts

Yuechun Shi, Shuiying Xiang, Xingxing Guo, Yahui Zhang, Hongji Wang, Dianzhuang Zheng, Yuna Zhang, Yanan Han, Yong Zhao, Xiaojun Zhu, Xiangfei Chen, Xun Li, Yue Hao. Photonic integrated spiking neuron chip based on a self-pulsating DFB laser with a saturable absorber[J]. Photonics Research, 2023, 11(8): 1382 Copy Citation Text

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Fig. 1. (a) Epitaxial wafer structure of the DFB-SA, (b) schematic of the fabricated DFB-SA chip, and (c) sample of the fabricated DFB-SA chip.

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(a) Experimental setup for a photonic spiking neuron based on the DFB-SA; (b) PI curves of the DFB-SA for VSA=0 V and VSA=−0.4 V; (c) optical spectra of the free-running DFB-SA for VSA=0 V, IG=99 mA and VSA=−0.4 V, IG=120 mA.

Fig. 2. (a) Experimental setup for a photonic spiking neuron based on the DFB-SA; (b) PI curves of the DFB-SA for VSA=0 V and VSA=−0.4 V; (c) optical spectra of the free-running DFB-SA for VSA=0 V, IG=99 mA and VSA=−0.4 V, IG=120 mA.

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Fig. 3. (a1)–(a3) Time series of period spike outputs; (b1)–(b3) the corresponding power spectra of the DFB-SA for different gain currents with VSA=−0.4 V, IG=115 mA, IG=120 mA, and IG=130 mA.

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Fig. 4. Spike frequency as a function of the gain current for different cases of VSA.

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Fig. 5. Excitability threshold property of DFB-SA subject to external perturbations. (a) The external stimulus; (b) the response output, the inset represents the enlargement of a single spike; (c) temporal maps plotting the response of the DFB-SA neuron to the arrival of 100 consecutive external stimuli with VSA=−0.4 V and IG=99.2 mA. The wavelength of the injected laser is 1548.61 nm.

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Fig. 6. Temporal integration behavior of the DFB-SA spiking neuron: (a) the external stimulus with pulse pairs having different ISIs; (b) the response with VSA=−0.4 V and IG=94 mA. The ISI for seven pulse pairs is, respectively, 0.40 ns, 0.48 ns, 0.64 ns, 0.66 ns, 0.80 ns, 0.86 ns, and 1.0 ns.

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$Refractory period behavior of the DFB-SA spiking neuron: (a) external stimulus with pulse pairs having different interspike interval; (b)–(f) the response under different conditions of the gain current. The gain current is, respectively, (b) 98.7 mA, (c) 104.4 mA, (d) 105.1 mA, (e) 111.0 mA, and (f) 112.1 mA. The ISI for seven pulse pairs is, respectively, 0.48 ns, 0.58 ns, 0.72 ns, 0.88 ns, 1.0 ns, 1.16 ns, and 1.24 ns.$

Fig. 7. Refractory period behavior of the DFB-SA spiking neuron: (a) external stimulus with pulse pairs having different interspike interval; (b)–(f) the response under different conditions of the gain current. The gain current is, respectively, (b) 98.7 mA, (c) 104.4 mA, (d) 105.1 mA, (e) 111.0 mA, and (f) 112.1 mA. The ISI for seven pulse pairs is, respectively, 0.48 ns, 0.58 ns, 0.72 ns, 0.88 ns, 1.0 ns, 1.16 ns, and 1.24 ns.

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Fig. 8. Schematic of the DFB-SA subject to external optical injection.

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Fig. 9. Numerical results of time series (left column) and power spectra (right column) of the self-pulsation output of the DFB-SA. (a) IG=45 mA, (b) IG=48 mA, and (c) IG=51 mA and ISA=0 mA.

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Fig. 10. Numerical results of the neuronlike response: (a) represents the stimuli; (b) represents the response with IG=41.7 mA and ISA=0 mA.

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Fig. 11. (a) The schematic of an ANN-to-SNN conversion using the photonics spiking neuron based on DFB-SA. (b) The activation function; the solid line is the curve of the measured data, and the dashed line is the corresponding polynomial fitting of the optical activation function. (c) The training and test accuracy for the MNIST dataset and (d) the confusion matrix of the inference task.

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Symbol	Description	Value
$κ$	Grating coupling coefficient	$1000 m^{- 1}$
$Λ$	Grating period	242.0589 nm
$λ_{B}$	Bragg wavelength	1550 nm
$L$	Length of the laser cavity	1500 μm
$L_{G}$	Length of the gain section	1480 μm
$L_{SA}$	Length of the SA section	20 μm
$w$	Width of the waveguide	2 μm
$d$	Thickness of the active layer	60 nm
$λ_{0}$	Reference wavelength	1550 nm
$A$	Linear recombination coefficient	$1 \times 10^{8} s^{- 1}$
$B$	Bimolecular recombination coefficient	$1 \times 10^{- 16} m^{3} / s$
$C$	Auger recombination coefficient	$3.5 \times 10^{- 41} m^{3} / s$
$α_{s}$	Internal loss	$5000 m^{- 1}$
$n_{eff 0}$	Effective refractive index	3.2
$n_{g}$	Group refractive index	3.6
$N_{T}$	Transparent carrier density	$1.5 \times 10^{24} m^{- 3}$
$α_{m}$	Linewidth enhancement factor	1
$Γ$	Confinement factor	0.08
$g_{N}$	Differential gain	$1.5 \times 10^{5} m^{- 1}$
$ε$	Gain suppression coefficient	$6 \times 10^{- 23} m^{3}$
$γ$	Spontaneous emission coefficient	$5 \times 10^{- 5}$