A new, low-cost, high-efficiency photonic integrated circuit
The rapid advancement in photonic integrated circuits (PICs), whichcombine multiple optical devices and functionalities on a single chip, has revolutionized optical communications and computing systems.
For decades, silicon-based PICs have dominated the field due to their cost-effectiveness and through their integration with existing semiconductor manufacturing technologies, despite their limitations with regard to their electro-optical modulation bandwidth. Nevertheless, silicon-on-insulator optical transceiver chips were successfully commercialized, driving information traffic through millions of glass fibers in modern datacenters.
Recently, the lithium niobate-on-insulator wafer platform has emerged as a superior material for photonic integrated electro-optical modulators due to its strong Pockels coefficient, which is essential for high-speed optical modulation. Nonetheless, high costs and complex production requirements, have kept lithium niobate from being adopted more widely, limiting its commercial integration.
Lithium tantalate (LiTaO3), a close relative of lithium niobate, promises to overcome these barriers. It features similar excellent electro-optic qualities but has an advantage over lithium niobate in scalability and cost, as it is already being widely used in 5G radiofrequency filters by telecom industries.
Now scientists led by Professor Tobias J. Kippenberg at EPFL and Professor Xin Ou at the Shanghai Institute of Microsystem and Information Technology (SIMIT) have created a new PIC platform based on lithium tantalate. The PIC leverages the material’s inherent advantages and can transform the field by making high-quality PICs more economically viable. The breakthrough is published in Nature.
The researchers developed a wafer-bonding method for lithium tantalate, whichis compatible with silicon-on-insulator production lines. They then masked the thin-film lithium tantalate wafer with diamond-like carbon and proceeded to etch optical waveguides, modulators, and ultra-high quality factor microresonators.
The etching was achieved by combining deep ultraviolet (DUV) photolithography and dry-etching techniques, developed initially for lithium niobate and then carefully adapted to etch the harder and more inert lithium tantalate. This adaptation involved optimizing the etch parameters to minimize optical losses, a crucial factor in achieving high performance in photonic circuits.
With this approach, the team was able to fabricate high-efficiency lithium tantalate PICs with an optical loss rate of just 5.6 dB/m at telecom wavelength. Another highlight is the electro-optic Mach-Zehnder modulator (MZM), a device widely used in today’s high-speed optical fiber communication. The lithium tantalate MZM offers a half-wave voltage-length product of 1.9 V cm and an electro-optical bandwidth reaching 40 GHz.
“While maintaining highly efficient electro-optical performance, we also generated soliton microcomb on this platform,” says Chengli Wang, the study’s first author. “These soliton microcombs feature a large number of coherent frequencies and, when combined with electro-optic modulation capabilities, are particularly suitable for applications such as parallel coherent LiDAR and photonic computing.”
The lithium tantalate PIC’s reduced birefringence (the dependence of refractive index on light polarization and propagation direction) allows dense circuit configurations and ensures broad operational capabilities across all telecommunication bands. The work paves the way for scalable, cost-effective manufacturing of advanced electro-optical PICs.
Journal: Nature
DOI: 10.1038/s41586-024-07369-1
Article Title: Lithium tantalate photonic integrated circuits for volume manufacturing.
Article Publication Date: 8-May-2024
Media Contact
All latest news from the category: Information Technology
Here you can find a summary of innovations in the fields of information and data processing and up-to-date developments on IT equipment and hardware.
This area covers topics such as IT services, IT architectures, IT management and telecommunications.
Newest articles
Innovative 3D printed scaffolds offer new hope for bone healing
Researchers at the Institute for Bioengineering of Catalonia have developed novel 3D printed PLA-CaP scaffolds that promote blood vessel formation, ensuring better healing and regeneration of bone tissue. Bone is…
The surprising role of gut infection in Alzheimer’s disease
ASU- and Banner Alzheimer’s Institute-led study implicates link between a common virus and the disease, which travels from the gut to the brain and may be a target for antiviral…
Molecular gardening: New enzymes discovered for protein modification pruning
How deubiquitinases USP53 and USP54 cleave long polyubiquitin chains and how the former is linked to liver disease in children. Deubiquitinases (DUBs) are enzymes used by cells to trim protein…