Thesis
Enhancing uniformity and integration scalability of photonic devices using selective transfer-printing techniques
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2025
- Thesis identifier
- T17564
- Person Identifier (Local)
- 202077907
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- The overall objective of this thesis is to develop and apply high-accuracy transfer-printing techniques for the integration of a wide variety of photonic devices onto heterogeneous photonic integrated circuit (PIC) platforms. These platforms span different material systems as well as a range of structural configurations. By allowing accurate, scalable, and flexible assembly of micro- and nanoscale photonic devices, this approach aims to improve the uniformity, production yield, and device density of next-generation photonic integrated circuits (PICs), and support their use in large-scale applications such as optical communications, sensing, and quantum technologies. This work began with the design and fabrication of supporting frames made of both photoresist and silica on silicon substrates, which were used to enable high-yield transfer printing of silicon photonic crystal cavity membranes designed to resonate at 1550 nm. The successful, high-accuracy transfer printing of silicon photonic crystal cavity (PhCC) membranes enabled large-scale and wavelength-based regrouping, achieving a yield of 119 out of 120. The reassembled membranes exhibited a significantly improved uniformity, with a mean wavelength shift of ±0.007nm and a standard deviation of ±0.021 nm, in contrast to the ∼ 1nm standard deviation observed in the as-fabricated membranes. Similar high accuracy transfer-printing techniques were then developed to enable the precise integration of nanoscale light sources into photonic circuits. Specifically, 20 InP semiconductor nanowires were deterministically embedded into 20 polymer (SU- 8) optical waveguides fabricated on high-quality glass substrates. A micro-LED-on-CMOS projection system was built and used to optically excite and modulate the InP nanowires via on-off keying at frequencies reaching hundreds of megahertz. The modulated infrared emission was effectively coupled into the waveguides and collected at the output facets, demonstrating the feasibility of integrating nanowire emitters into scalable photonic platforms. This work represents the first demonstration of nanowire modulation using incoherent visible light sources, although lasing was not achieved due to free-space optical losses. 16 GaN-based micro-LED pixels with dimensions of 100×100 μm2 were transfer-printed onto an optimised chip featuring nanowires (NWs) embedded in polymer waveguides, with a PDMS adhesion layer, to improve scalability and enable an on-chip optical pumping system. 15 out of the 16 pixels were successfully probed and modulated using relatively small-signal excitation at effective frequencies in the tens of megahertz, thereby enabling corresponding modulation of the embedded nanowires. Additionally, the emission of polymer waveguides was shown and analysed. The high-yield and high-accuracy transfer-printing technique significantly improves the uniformity and scalability in the large-scale fabrication and integration of photonic devices. By enabling precise placement across diverse substrates and material platforms, this approach addresses fabrication non-uniformities and supports the assembly of complex photonic systems. These results highlight the potential of transfer printing as a key enabling technology for next-generation integrated photonics.
- Advisor / supervisor
- Strain, Michael
- Resource Type
- DOI
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PDF of thesis T17564 | 2026-02-17 | Public | Download |