N231-078 TITLE: Phase Trimming for Integrated Photonics

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Hypersonics; Microelectronics; Nuclear

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: Development of simultaneously low power, low optical loss, and small die area technologies that combat integrated photonics device phase errors at visible and near-infrared wavelengths.

DESCRIPTION: Integrated photonic devices suffer from phase errors introduced by fabrication and material deposition variations across reticles, across individual wafers, and between wafers. Mitigation of phase errors through optical phase trimming will enable larger devices, which will greatly improve photonic system performance in light-starved applications: shorter integration times, resolution, longer ranges, and higher signal-to-noise ratio for applications such as optical communications and LiDAR [Ref 1]. The most mature phase control technologies typically have one or more of the following drawbacks: 1) large size, 2) active phase control devices often have high power consumption, and 3) high optical loss, especially at visible and near infrared wavelengths. Addressing these challenges will advance photonics.

Over the past decade, work has gone into some of the following areas, among others: liquid crystal technology [Ref 2], focused-ion-beam (FIB), laser writing, and micro/nano-electromechanical systems (M/NEMS) switches [Ref 3]. Both static and active phase error correction solutions are encouraged to respond to this SBIR topic. Similarly, both the evolution of academic techniques as well as the adaptation and maturation of known techniques to this problem are of interest. Zero-power-hold solutions are of particular interest.

One novel area of interest is phase change materials [Refs 4, 5] � a reliable and repeatable supply is crucial for use by academia, foundries, and government research laboratories. A full solution is not required for answering this SBIR topic. This work could include improving uniformity of material targets, improving repeatability of material properties, and formulating new materials for low optical loss, particularly at shorter wavelengths.

This technology should focus on visible and near-infrared (NIR) wavelengths, particularly between 700-900 nm, and be compatible with silicon (Si) and silicon-nitride (SiN) processes. A path toward integration with densely-packed waveguide arrays is necessary. As the technology is matured, performers will collaborate with SSP and government contractors to integrate the technology into relevant platforms. This collaboration will also seek to develop a technology transfer plan for commercial-scale photonics foundry fabrication.

PHASE I: Perform a design and fabrication analysis to assess the feasibility of the proposed technique or material development for producing phase trimming capability in the near-infrared (across 700-900 nm) for use in integrated photonic devices. Include the expected dynamic range for the technique (up to 2pi optical phase shift is preferred), expected die area required (< 100 �m2 or capable of individual addressability within waveguide arrays with < 5 �m center-to-center spacing is preferred), optical loss introduced (< 1 dB insertion loss preferred), and energy required for switching. For materials development efforts, report optical properties (refractive index and extinction coefficient) for amorphous, crystalline, and attainable intermediate phases, expected conditions (temperature, electric field, etc.) and energy required for switching, and comparison to current materials. Identify risks and risk mitigation strategies. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build prototype solutions in Phase II.

PHASE II: Fabricate and characterize five (5) prototypes that demonstrate the phase trimming capability or material system. Variability of key metrics (optical phase shift, refractive index change) > 3% and optical insertion loss > 1 dB should be addressed with a mitigation plan to enable highly reliable performance as the system matures.

The final report will include a discussion of potential near-term and long-term development efforts that would improve the technology�s performance, ease of fabrication, and integration in the required small die area. It will also include an evaluation of the cost of fabrication and how that might be reduced in the future. The prototypes should be delivered by the end of Phase II.

PHASE III DUAL USE APPLICATIONS: Based on the prototypes and continual advancement of photonics, a low SWaP phase trimming capability should lead to dramatic improvements in the scaling phase-sensitive photonic devices. Support the Navy in transitioning the technology to Navy use. The prototypes will be evaluated through optical characterization and testing with relevant adjacent devices. The end product technology could be leveraged to bring photonic imaging and sensing towards a more mature state with a lower SWaP profile that could make it more attractive for optical communication and Light Detecting and Ranging (LiDAR) as well as in the biomedical, navigation, and vehicle autonomy markets.

REFERENCES:

1.       Clevenson, Hannah A. et al. "Incoherent Light Imaging Using an Optical Phased Array.", Applied Physics Letters 116, 031105 (2020). https://doi.org/10.1063/1.5130697

2.       J. Notaros, M. Notaros, M. Raval, and M. R. Watts, "Liquid-Crystal-Based Visible-Light Integrated Optical Phased Arrays," in Conference on Lasers and Electro-Optics, OSA Technical Digest (Optica Publishing Group, 2019), paper STu3O.3.

3.       K. Van Acoleyen, J. Roels, P. Mechet, T. Claes, D. Van Thourhout and R. Baets, "Ultracompact Phase Modulator Based on a Cascade of NEMS-Operated Slot Waveguides Fabricated in Silicon-on-Insulator," in IEEE Photonics Journal, vol. 4, no. 3, pp. 779-788, June 2012, doi: 10.1109/JPHOT.2012.2198880

4.       Abdollahramezani, Sajjad, Hemmatyar, Omid, Taghinejad, Hossein, Krasnok, Alex, Kiarashinejad, Yashar, Zandehshahvar, Mohammadreza, Alù, Andrea and Adibi, Ali. "Tunable nanophotonics enabled by chalcogenide phase-change materials" Nanophotonics, vol. 9, no. 5, 2020, pp. 1189-1241. https://doi.org/10.1515/nanoph-2020-0039

5.       Delaney, Matthew et al. "A New Family of Ultralow Loss Reversible Phase-Change Materials for Photonic Integrated Circuits: Sb2S3 and Sb2Se3", Advanced Functional Materials 30, 2002447 (2020). 0.1002/adfm.202002447

 

KEYWORDS: Photonic integrated circuits, phase change materials, optical phase trimming, photonic imaging, optical phase shifters, visible and near infrared photonics

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