67 GHz light-trapping-structure germanium photodetector supporting 240 Gb/s PAM-4 transmission

Daigao Chen; Hongguang Zhang; Min Liu; Xiao Hu; Yuguang Zhang; Dingyi Wu; Peiqi Zhou; Siyao Chang; Lei Wang; Xi Xiao

doi:10.1364/PRJ.455291

Journals >Photonics Research >Volume 10 >Issue 9 >Page 2165 > Article

Photonics Research
Vol. 10, Issue 9, 2165 (2022)

67 GHz light-trapping-structure germanium photodetector supporting 240 Gb/s PAM-4 transmission

Daigao Chen^1、2、†, Hongguang Zhang^1、†, Min Liu¹, Xiao Hu^1、2, Yuguang Zhang^1、2, Dingyi Wu¹, Peiqi Zhou¹, Siyao Chang¹, Lei Wang^1、2、3, and Xi Xiao^{1、2、3、*}

Author Affiliations

¹National Information Optoelectronics Innovation Center, China Information and Communication Technologies Group Corporation (CICT), Wuhan 430074, China

²State Key Laboratory of Optical Communication Technologies and Networks, China Information and Communication Technologies Group Corporation (CICT), Wuhan 430074, China

³Peng Cheng Laboratory, Shenzhen 518055, China

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DOI: 10.1364/PRJ.455291 Cite this Article Set citation alerts

Daigao Chen, Hongguang Zhang, Min Liu, Xiao Hu, Yuguang Zhang, Dingyi Wu, Peiqi Zhou, Siyao Chang, Lei Wang, Xi Xiao. 67 GHz light-trapping-structure germanium photodetector supporting 240 Gb/s PAM-4 transmission[J]. Photonics Research, 2022, 10(9): 2165 Copy Citation Text

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Schematic of the light-trapping-structure Ge PD: (a) 3D view, (b) top view, and (c) side view along the incident direction; (b) and (c) hide all metal layers. Doping is not shown.

Fig. 1. Schematic of the light-trapping-structure Ge PD: (a) 3D view, (b) top view, and (c) side view along the incident direction; (b) and (c) hide all metal layers. Doping is not shown.

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Field distributions at different wavelengths in the proposed PD. (a)–(d) Distributions in silicon layer and (e)–(h) distributions in germanium layer.

Fig. 2. Field distributions at different wavelengths in the proposed PD. (a)–(d) Distributions in silicon layer and (e)–(h) distributions in germanium layer.

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Fig. 3. Calculated responsivity of the circular Ge PD.

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Fig. 4. Optical micrograph of the fabricated circular Ge PD.

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Fig. 5. (a) Dark current versus voltage and (b) normalized responsivity at different wavelengths.

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Fig. 6. Normalized frequency response of the proposed Ge PD.

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Fig. 7. (a) Experiment setup of high-speed PAM-4 signal transmission system and (b) BTB eye diagram of 80, 90, 100, and 105 GBaud PAM-4 signals.

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Fig. 8. (a) BER versus different bit rates with BTB, 1 km, and 2 km transmissions; (b) BTB BER of 200 Gb/s PAM-4 versus different optical power.

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Reference		Structure of Ge	3 dB Bandwidth (GHz)	Responsivity (A/W)	Dark Current (nA)	Dark Current Density ( $mA / {cm}^{2}$ )
[9]		Rectangle ( $0.1 \times 10 {μm}^{2}$ )	265 at 2 V	0.3 at 1550 nm	$\leq 200$ at 2 V	$\leq 5000$ ^a
[10]		Rectangle ( $0.5 \times 14.2 {μm}^{2}$ )	67 at 1 V	0.74 at 1550 nm $\sim 0.52$ at 1570 nm	3.6 at 2 V	$\sim 158$ ^a
[24]		Rectangle	67 at 2 V	0.9 at 1550 nm	–	90 at 1 V
[25]	Rectangle ( $3 \times 15 {μm}^{2}$ )		42 at 4 V	1 at 1550 nm $\sim 0.58$ at 1580 nm (with edge coupler)	18 at 1 V	60
[26]		Rectangle ( $7.4 \times 50 {μm}^{2}$ )	31 at 2 V	0.89 at 1550 nm $\sim 0.82$ at 1580 nm	169 at 2 V	51
[29]		Rectangle ( $1.5 \times 12 {μm}^{2}$ )	40 at 1 V	0.7 at 1550 nm $\sim 0.5$ at 1580 nm	1.16 at 1 V	$\sim 6$ ^a
[30]		Rectangle ( $1.3 \times 4 {μm}^{2}$ )	45 at 1 V	0.8 at 1500 nm (TM mode)	3 at 1 V	$\sim 57$ ^a
Our previous work		Rectangle ( $4 \times 20 {μm}^{2}$ )	35 at 3 V	0.85 at 1550 nm	20 at 2 V	25
This work		Circular ( $9 \times π {μm}^{2}$ )	67 at 2 V	1.05 at 1550 nm 0.78 at 1580 nm	6.4 at 2 V	23