Low-noise Kerr frequency comb generation with low temperature deuterated silicon nitride waveguides

Wu, Zeru; Zhang, Yanfeng; Zeng, Shihao; Li, Jiaqi; Xie, Yaozu; Chen, Yujie; Yu, Siyuan

doi:10.1364/oe.438436

Cited by 17 publications

(8 citation statements)

References 38 publications

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“…The Si 3 N 4 PIC is fabricated using the DUV subtractive process. Figure 1d shows the subtractive process flow widely used to fabricate PIC based on essentially any material, particularly Si 3 N 4 [35][36][37][40][41][42][43][44]. First, a Si 3 N 4 film is deposited on a clean thermal wet SiO 2 substrate via low-pressure chemical vapor deposition (LPCVD).…”

Section: Fabricationmentioning

confidence: 99%

“…Top SiO 2 cladding is then deposited on the wafer, which also requires high-temperature annealing to remove silicon-hydrogen bonds that also cause absorption loss. In specific cases where deuterated plasma-enhanced chemical vapor deposition (PECVD) Si 3 N 4 [44,45] and SiO 2 [46] are used, thermal annealing may not be required as these films are intrinsically hydrogen-free.…”

Section: Fabricationmentioning

confidence: 99%

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Foundry manufacturing of tight-confinement, dispersion-engineered, ultralow-loss silicon nitride photonic integrated circuit

Ye,

Jia,

Huang

et al. 2023

Preprint

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The foundry development of integrated photonics has revolutionized today's optical interconnect and datacenters. Over the last decade, we have witnessed the rising of silicon nitride (Si 3 N 4 ) integrated photonics, which is currently transferring from laboratory research to foundry manufacturing. The development and transition are triggered by the ultimate need of low optical loss offered by Si 3 N 4 , which is beyond the reach of silicon and III-V semiconductors. Combined with modest Kerr nonlinearity, tight optical confinement and dispersion engineering, Si 3 N 4 has today become the leading platform for linear and Kerr nonlinear photonics, and has enabled chip-scale lasers featuring ultralow noise on par with table-top fiber lasers. However, so far all the reported fabrication processes of tight-confinement, dispersion-engineered Si 3 N 4 photonic integrated circuit (PIC) with optical loss down to few dB/m have only been developed on 4-inch or smaller wafers. Yet, to transfer these processes to established CMOS foundries that typically operate 6-inch or even larger wafers, challenges remain. In this work, we demonstrate the first foundry-standard fabrication process of Si 3 N 4 PIC with only 2.6 dB/m loss, thickness above 800 nm, and near 100% fabrication yield on 6-inch wafers. Such thick and ultralow-loss Si 3 N 4 PIC enables low-threshold generation of soliton frequency combs. Merging with advanced heterogeneous integration, active ultralow-loss Si 3 N 4 integrated photonics could pave an avenue to addressing future demands in our increasingly information-driven society.

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Section: Fabricationmentioning

confidence: 99%

Section: Fabricationmentioning

confidence: 99%

Foundry manufacturing of tight-confinement, dispersion-engineered, ultralow-loss silicon nitride photonic integrated circuit

Ye,

Jia,

Huang

et al. 2023

Preprint

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show abstract

“…Optical frequency combs (OFCs), consisting of equidistantly spaced spectral lines with fixed phase relationships, have been extensively demonstrated in integrated micro-ring cavities. [33][34][35] In our previous works, different low-noise states, including soliton crystal [36] and single soliton [37] have been successfully generated in high-quality (Q) factor anomalous dispersion micro-ring resonators on a deuterated silicon nitride platform, and also from micro-rings with embedded gratings on the inner sidewall. [38,39] In recent years, normal-dispersion OFCs have gained increased attention due to their high conversion efficiency and feedbackfree operation.…”

Section: Introductionmentioning

confidence: 99%

Coherent Optical Comb Generation in the Joint Space of Frequency and Topological Charge

Li,

Zeng,

Xie

et al. 2024

Laser & Photonics Reviews

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Coherent photonic states in the frequency domain or optical frequency combs are investigated widely over the past decade. Meanwhile, photonic states based on spatial coherence, in particular optical vortex states, have also been studied extensively. Further exploitation of coherent photonics state in hitherto unexplored higher dimensional spaces can reveal new realms of physics. The on‐chip generation of coherent optical combs in the 2D parameter space of frequency and topological charge is reported. Using a micro‐ring resonator embedded with angular gratings, optical frequency combs are generated by Kerr nonlinearity. The coherent comb lines, with their frequencies inherently matching the cavity resonances, are immediately diffracted by the angular grating to emit an ensemble of coherent spatial photonic states with each state carrying distinctive spin and orbital angular momenta. The mapping between the frequency and the topological charge dimensions leads to the construction of coherent combs in the high‐dimensional frequency‐topological charge (f‐l) space. Operating the device in the normal‐dispersion regime enables the adjustment of comb line spacing from 1 to 11 free spectral ranges by selectively pumping different cavity resonances with high pump‐to‐comb conversion efficiency. Such on‐chip reconfigurable high‐dimensional coherent optical combs open avenues for innovative exploration of physics.

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“…In recent years, low-temperature deposited Si 3 N 4 films have attracted increasing interest in 3D hybrid integration of Si 3 N 4 with other materials. [18,21,[29][30][31][32] Among different low-temperature deposition methods, PECVD and ICP-CVD are widely used as lowtemperature (<400°C), and CMOS compatible processes, providing high-thickness Si 3 N 4 films (>1 μm) without cracks. However, the optical loss within the deposited films at telecommunication wavelengths is usually high (typically 200 dB m −1 ) due to the absorption of Si─H and N─H bonds, [33] which poses a challenge for optical applications.…”

Section: Introductionmentioning

confidence: 99%

Low‐Temperature Sputtered Ultralow‐Loss Silicon Nitride for Hybrid Photonic Integration

Zhang,

Bi,

Harder

et al. 2023

Laser & Photonics Reviews

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Silicon‐nitride‐on‐insulator (Si3N4) photonic circuits have seen tremendous advances in many applications, such as on‐chip frequency combs, Lidar, telecommunications, and spectroscopy. So far, the best film quality has been achieved with low pressure chemical vapor deposition (LPCVD) and high‐temperature annealing (1200°C). However, high processing temperatures pose challenges to the cointegration of Si3N4 with pre‐processed silicon electronic and photonic devices, lithium niobate on insulator (LNOI), and Ge‐on‐Si photodiodes. This limits LPCVD as a front‐end‐of‐line process. Here, ultralow‐loss Si3N4 photonics based on room‐temperature reactive sputtering is demonstrated. Propagation losses as low as 5.4 dB m−1 after 400°C annealing and 3.5 dB m−1 after 800°C annealing are achieved, enabling ring resonators with highest optical quality factors of > 10 million and an average quality factor of 7.5 million. To the best of the knowledge, these are the lowest propagation losses achieved with low temperature Si3N4. This ultralow loss enables the generation of microresonator soliton frequency combs with threshold powers of 1.1 mW. The introduced sputtering process offers full complementary metal oxide semiconductor (CMOS) compatibility with front‐end silicon electronics and photonics. This could enable hybrid 3D integration of low loss waveguides with integrated lasers and lithium niobate on insulator.

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Low-noise Kerr frequency comb generation with low temperature deuterated silicon nitride waveguides

Cited by 17 publications

References 38 publications

Foundry manufacturing of tight-confinement, dispersion-engineered, ultralow-loss silicon nitride photonic integrated circuit

Foundry manufacturing of tight-confinement, dispersion-engineered, ultralow-loss silicon nitride photonic integrated circuit

Coherent Optical Comb Generation in the Joint Space of Frequency and Topological Charge

Low‐Temperature Sputtered Ultralow‐Loss Silicon Nitride for Hybrid Photonic Integration

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