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Method And Process For Tantala Integrated Nonlinear Photonics
Published Patent Application Number: 2021/0055627 A1
Abstract
Integrated photonics that enable nonlinear optical processes are important for numerous applications, including precision metrology; microresonator frequency comb generation; optical signal generation and processing; sensing, positioning, and navigation; and generation and manipulation of quantum information. We have developed a new material platform for integrated nonlinear photonics based on tantalum pentoxide (tantala), which offers important advantages compared to the existing state of practice in nonlinear photonics. Our invention enables high-performance nonlinear photonics devices (eg. Microresonator frequency combs) to be created at lower cost and higher yield than existing technologies. We seek patent protection for the method and process of tantala nonlinear photonics because this is an important advanced technology within a large US and international commercial market segment. Therefore, a patent would protect US interests in developing advanced photonics.
patent description
The invention is a method and process to create integrated nonlinear photonics, using the material tantalum pentoxide (Ta2O5, also known as tantala). Our innovation is use of the tantala material and demonstration of the properties needed to support nonlinear processes like microresonator frequency comb generation. We use deposited tantala material on oxidized silicon wafers, and we fabricate integrated nonlinear photonics devices, using standard semiconductor processing techniques.
We have developed all of the procedures to fabricate integrated nonlinear photonics with tantala, taking advantage for the first time the superior properties of this material. Specifically, we have identified the material deposition, lithography, chemical etching, and thermal processing approaches to realize integrated nonlinear photonics devices. We have demonstrated the superior properties of tantala, namely low tensile stress that enables high-yield fabrication, low optical losses efficiently excite nonlinear processes, and a low thermal processing temperature to maintain process compatibility for co-integration with other photonics materials.
Tantala solves critical problems in nanofabrication, compared to other materials like silicon nitride that represent the current state-of-practice. Therefore, tantala will be an important material platform that can offer higher yield of devices designed for integrated nonlinear photonics. Moreover, tantala has a reduced thermal processing requirement, which maintains compatibility with other integrated photonics processes better than silicon nitride.
We have not observed limitations with the tantala platform in terms of realizing comparable performance to existing state-of-the-art material platforms like silicon nitride. However, challenges with tantala may arise with respect to material stability and thermally driven crystallization.
Features
The invention of tantala offers several features that are commercially and technically superior to existing materials. Tantala itself offers superior material properties for integrated nonlinear photonics compared to silicon nitride, which represents the current state-of-practice. The key properties that make tantala attractive for commercialization of nonlinear photonics are: low optical losses to enable efficient nonlinear photonics processes, wider optical transparency window, low tensile stress for high yield in nanofabrication, and relatively low thermal processing temperature to maintain compatibility for co-integration with other integrated photonics materials.