Athermal 4-channel (de-)multiplexer in silicon nitride fabricated at low temperature

Shiqi Tao; Qingzhong Huang; Liangqiu Zhu; Jun Liu; Yinglu Zhang; Ying Huang; Yi Wang; Jinsong Xia

doi:10.1364/PRJ.6.000686

Journals >Photonics Research >Volume 6 >Issue 7 >Page 686 > Article

Photonics Research
Vol. 6, Issue 7, 686 (2018)

Athermal 4-channel (de-)multiplexer in silicon nitride fabricated at low temperature

Shiqi Tao¹, Qingzhong Huang^1、2、*, Liangqiu Zhu¹, Jun Liu¹, Yinglu Zhang¹, Ying Huang¹, Yi Wang¹, and Jinsong Xia^1、3、*

Author Affiliations

¹Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China

²e-mail: huangqz@mail.hust.edu.cn

³e-mail: jsxia@hust.edu.cn

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DOI: 10.1364/PRJ.6.000686 Cite this Article Set citation alerts

Shiqi Tao, Qingzhong Huang, Liangqiu Zhu, Jun Liu, Yinglu Zhang, Ying Huang, Yi Wang, Jinsong Xia. Athermal 4-channel (de-)multiplexer in silicon nitride fabricated at low temperature[J]. Photonics Research, 2018, 6(7): 686 Copy Citation Text

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Fig. 1. Schematics of the athermal (a) MZI filter and (b) 4-channel MZI (de-)multiplexer.

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(a) Simulated effective index and TOC of the TE0 mode; inset: cross section of SiN waveguide. (b)–(d) Field profiles of the TE0 mode for W=0.44 μm, 1.2 μm, and 1.8 μm, respectively.

Fig. 2. (a) Simulated effective index and TOC of the TE0 mode; inset: cross section of SiN waveguide. (b)–(d) Field profiles of the TE0 mode for W=0.44 μm, 1.2 μm, and 1.8 μm, respectively.

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Fig. 3. (a) Optical microscope image of the athermal 4-channel (de-)multiplexer. SEM images of (b) a 2×2 MMI, (c) narrow waveguide and normal waveguide connected by a taper, (d) wide waveguide and normal waveguide connected by a taper, and (e) grating coupler for vertical coupling.

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Fig. 4. Transmission spectra of MZI filters at different temperatures for (a) L=410 μm, (b) L=430 μm, (c) L=450 μm, and (d) L=470 μm. (e) Wide transmission spectrum of the MZI filter with L=450 μm.

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Fig. 5. (a) Thermal sensitivity as a function of L. (b) Thermal sensitivity as a function of wavelength.

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Fig. 6. Measured normalized transmission spectra of (a) conventional MZI (de-)multiplexer and (b) athermal MZI (de-)multiplexer.

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Fig. 7. Spectral shift with temperature for (a) Ch. 1, (b) Ch. 2, (c) Ch. 3, and (d) Ch. 4.

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	Ch. 1		Ch. 2		Ch. 3		Ch. 4
Center wavelength (nm)	1293.6		1297.7		1301.9		1306.1
Crosstalk at center (dB)	−30		−25		−22		−23
1-dB bandwidth (nm)	2.2		2.2		2.2		2.2
Insertion loss (dB)	5.5		5.2		5.5		5.5
Channel spacing (nm)		4.3		4.0		4.2

Table 1. Room-Temperature Performance of the Athermal MZI (De-)Multiplexer

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Ref.	Material	Device	$d λ / d T$ (pm/°C)	IL (dB)	ET/XT (dB)
Dwivedi et al. [22]	Silicon	MZI filter	$< \pm 15$ (in 40 nm)	0.3	−25
Yang et al. [24]	Silicon	MZI filter	$< \pm 10$ (in 30 nm)	N.A.	−30
Xing et al. [23]	Silicon	MZI filter	$< \pm 2.5$ (in 60 nm)	1	−10
Our device	SiN (PECVD)	MZI filter	$< \pm 2.0$ (in 55 nm)	2.6	−30
Hassan et al. [25]	Silicon	MZI MUX 4	$< 22$ (all channels)	4.3	−15
Gao et al. [30]	SiN (LPCVD)	MZI MUX 4	18.7 (central channel)	1.8	−20
Bucio et al. [36]	SiN (PECVD)	AMMI MUX 3	10 (central channel)	2.5	−18
Our device	SiN (PECVD)	MZI MUX 4	$< 4.8$ (all channels)	5.5	−22

Table 2. Performance Comparison of the MZI Filters and (De-)Multiplexers with Low Thermal Sensitivity (MUX, multiplexer; IL, insertion loss; ET, extinction ratio for MZI filter; XT, crosstalk for MUX)