Silicon Nitride Spot-Size Converter with Coupling Loss < 1.5 dB for Both Polarizations at 1W Optical Input

Microwave photonics (MWP) applications often require a high optical input power (>100 mW) to achieve an optimal signal-to-noise ratio (SNR). However, conventional silicon spot-size converters (SSCs) are susceptible to high optical power due to the two-photon absorption (TPA) effect. To overcome t...

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Main Authors: Enge Zhang, Yu Zhang, Lei Zhang, Xu Yang
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Photonics
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Online Access:https://www.mdpi.com/2304-6732/12/1/5
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author Enge Zhang
Yu Zhang
Lei Zhang
Xu Yang
author_facet Enge Zhang
Yu Zhang
Lei Zhang
Xu Yang
author_sort Enge Zhang
collection DOAJ
description Microwave photonics (MWP) applications often require a high optical input power (>100 mW) to achieve an optimal signal-to-noise ratio (SNR). However, conventional silicon spot-size converters (SSCs) are susceptible to high optical power due to the two-photon absorption (TPA) effect. To overcome this, we introduce a silicon nitride (SiN) SSC fabricated on a silicon-on-insulator (SOI) substrate. When coupled to a tapered fiber with a 4.5 μm mode field diameter (MFD), the device exhibits low coupling losses of <0.9 dB for TE modes and <1.4 dB for TM modes at relatively low optical input power. Even at a 1W input power, the additional loss is minimal, at approximately 0.1 dB. The versatility of the SSC is further demonstrated by its ability to efficiently couple to fibers with MFDs of 2.5 μm and 6.5 μm, maintaining coupling losses below 1.5 dB for both polarizations over the entire C-band. This adaptability to different mode diameters makes the SiN SSC a promising candidate for future electro-optic chiplets that integrate heterogeneous materials such as III-V for gain and lithium niobate for modulation with the SiN-on-SOI for all other functions using advanced packaging techniques.
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spelling doaj-art-0a2f471fe7a0470db80109f20e24c7ca2025-01-24T13:46:09ZengMDPI AGPhotonics2304-67322024-12-01121510.3390/photonics12010005Silicon Nitride Spot-Size Converter with Coupling Loss < 1.5 dB for Both Polarizations at 1W Optical InputEnge Zhang0Yu Zhang1Lei Zhang2Xu Yang3State Key Laboratory of Information Photonics and Optical Communications, School of Integrated Circuits, Beijing University of Posts and Telecommunications, Beijing 100876, ChinaThe 54th Research Institute of China Electronics Technology Group Corporation, Shijiazhuang 050081, ChinaState Key Laboratory of Information Photonics and Optical Communications, School of Integrated Circuits, Beijing University of Posts and Telecommunications, Beijing 100876, ChinaThe 54th Research Institute of China Electronics Technology Group Corporation, Shijiazhuang 050081, ChinaMicrowave photonics (MWP) applications often require a high optical input power (>100 mW) to achieve an optimal signal-to-noise ratio (SNR). However, conventional silicon spot-size converters (SSCs) are susceptible to high optical power due to the two-photon absorption (TPA) effect. To overcome this, we introduce a silicon nitride (SiN) SSC fabricated on a silicon-on-insulator (SOI) substrate. When coupled to a tapered fiber with a 4.5 μm mode field diameter (MFD), the device exhibits low coupling losses of <0.9 dB for TE modes and <1.4 dB for TM modes at relatively low optical input power. Even at a 1W input power, the additional loss is minimal, at approximately 0.1 dB. The versatility of the SSC is further demonstrated by its ability to efficiently couple to fibers with MFDs of 2.5 μm and 6.5 μm, maintaining coupling losses below 1.5 dB for both polarizations over the entire C-band. This adaptability to different mode diameters makes the SiN SSC a promising candidate for future electro-optic chiplets that integrate heterogeneous materials such as III-V for gain and lithium niobate for modulation with the SiN-on-SOI for all other functions using advanced packaging techniques.https://www.mdpi.com/2304-6732/12/1/5silicon photonicsspot-size convertermicrowave photonics
spellingShingle Enge Zhang
Yu Zhang
Lei Zhang
Xu Yang
Silicon Nitride Spot-Size Converter with Coupling Loss < 1.5 dB for Both Polarizations at 1W Optical Input
Photonics
silicon photonics
spot-size converter
microwave photonics
title Silicon Nitride Spot-Size Converter with Coupling Loss < 1.5 dB for Both Polarizations at 1W Optical Input
title_full Silicon Nitride Spot-Size Converter with Coupling Loss < 1.5 dB for Both Polarizations at 1W Optical Input
title_fullStr Silicon Nitride Spot-Size Converter with Coupling Loss < 1.5 dB for Both Polarizations at 1W Optical Input
title_full_unstemmed Silicon Nitride Spot-Size Converter with Coupling Loss < 1.5 dB for Both Polarizations at 1W Optical Input
title_short Silicon Nitride Spot-Size Converter with Coupling Loss < 1.5 dB for Both Polarizations at 1W Optical Input
title_sort silicon nitride spot size converter with coupling loss 1 5 db for both polarizations at 1w optical input
topic silicon photonics
spot-size converter
microwave photonics
url https://www.mdpi.com/2304-6732/12/1/5
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AT yuzhang siliconnitridespotsizeconverterwithcouplingloss15dbforbothpolarizationsat1wopticalinput
AT leizhang siliconnitridespotsizeconverterwithcouplingloss15dbforbothpolarizationsat1wopticalinput
AT xuyang siliconnitridespotsizeconverterwithcouplingloss15dbforbothpolarizationsat1wopticalinput