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Photoelastic birefringence of copolymers with non-planar structure
摘要： We demonstrate the utility of nonplanar building blocks to tune the polymer photoelastic birefringence and obtain near zero and negative photoelastic coefficients. Photoelastic properties of two novel random copolymers systems: 2-vinlypyridene (2VP)-hydroxyadmantyl methacrylate (HAMA) and vinyl pyrrollidone (VP)-isobornylacrylate (iBOA) were investigated at a function of comonomer composition. Photoelastic coefficient of the copolymers could be facilely tuned by changing the copolymer composition. In particular, we show that negative stress optic coefficient could be obtained from VP - iBOA copolymers and near zero stress optic coefficient could be obtained from 2VP -HAMA copolymers. In addition, we investigate the effect of addition of triethylene glycol (TEG) as a plasticizer on the photoelastic properties for the 2VP-HAMA copolymers. We found that addition of TEG led to a reduction in both the polymer Tg and photoelastic coefficient. Our study indicates that bulky non-planar side groups in the polymer backbone tend to induce negative photoelastic birefringence and can be utilized as important building blocks for the design of optical polymers.
关键词： Optical polymers,Photoelasticity,Birefringence
更新于2025-09-23 15:23:52
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Modeling the Diffraction Efficiency of Reflective-Type PQ-PMMA VBG Using Simplified Rate Equations
摘要： A simulation based on the rate equations was performed to analyze the concentration distribution of molecules in phenanthrenequinone (PQ) doped polymethyl methacrylate (PMMA) polymers (PQ-PMMAs) exposed using a two-beam interference configuration. The concentration distributions were used to predict the diffraction efficiency of PQ-PMMA-based volume Bragg gratings (VBGs) by using the transfer matrix method. The simulation results suggest that an intermittent exposure method can promote the diffusion of PQ molecules and increase the final diffraction efficiency. A series of experiments validated our hypothesis that the diffraction efficiency of reflective-type PQ-PMMA VBG can be predicted.
关键词： Bragg gratings,holographic optical components,optical polymers
更新于2025-09-23 15:22:29
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Evidence of reversible oxidation at CuInSe <sub/>2</sub> grain boundaries
摘要： Silicon photonics leverages microelectronic fabrication facilities to achieve photonic circuits of unprecedented complexity and cost efficiency. This efficiency does not yet translate to optical packaging, however, which has not evolved substantially from legacy devices. To reach the potential of silicon photonics, we argue that disruptive advances in the packaging cost, scalability in the optical port count, and scalability in the manufacturing volume are required. To attain these, we establish a novel photonic packaging direction based on leveraging existing microelectronics packaging facilities. We demonstrate two approaches to fiber-to-chip interfacing and one to hybrid photonic integration involving direct flip-chip assembly of photonic dies. Self-alignment is used throughout to compensate for insufficient placement accuracy of high-throughput pick and place tools. We show a self-aligned peak transmission of –1.3 dB from standard cleaved fibers to chip and of –1.1 dB from chip to chip. The demonstrated approaches are meant to be universal by simultaneously allowing wide spectral bandwidth for coarse wavelength division multiplexing and large optical-port count.
关键词： flip-chip devices,optical fiber communication,Integrated optoelectronics,packaging,optical polymers
更新于2025-09-23 15:19:57
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<i>(Keynote)</i> Silicon-Organic Hybrid Photonics: Integration of Electro-Optical Polymers in a Photonic Integrated Circuit Technology
摘要： In this work, we present recent results on the hybrid integration of electro-optical organic materials in a photonic integrated circuit (PIC) technology. We review some of the identified challenges regarding process compatibility and present preliminary results on the integration of organic materials in a PIC technology using a 0.25 μm SiGe BiCMOS pilotline. Here, we are focusing on electro-optical applications towards high-speed modulators with ultra-low energy consumption.
关键词： Ultra-Low Energy Consumption,Silicon-Organic Hybrid Photonics,Electro-Optical Polymers,High-Speed Modulators,Photonic Integrated Circuit
更新于2025-09-16 10:30:52
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On the Characterization of Novel Step-Index Biocompatible and Biodegradable poly(D,L- lactic acid) Based Optical Fiber
摘要： We report on the first step-index biodegradable polymer optical fiber (bioPOF) fabricated using commercially available polyesters, with a core made from poly(D,L-lactic-co-glycolic acid) and a cladding made from poly(D,L-lactic acid). We prepared the preforms with a rod-in-tube technique and the fibers with a standard heat drawing process. We discuss the chemical and optical properties of the polyesters along the fabrication process from polymer granulates to optical fiber. More specifically, we address the influence of the processing steps on the molecular weight and thermal properties of the polymers. Cutback measurements return an attenuation of 0.26 dB∕cm at 950 nm for fibers with an outer diameter of 1000 ± 50 μm, a core of 570 ±30 μm and a numerical aperture of 0.163. When immersed in phosphate-buffered saline (PBS), bioPOFs degrade over a period of 3 months, concurrent with a 91% molecular weight loss. The core decomposes already after 3 weeks and features a 85% molecular weight loss. There is no any additional optical loss caused by immersion in PBS during the first 30-40 min for a bioPOFs with a diameter of about 500 μm. Our result demonstrates that bioPOF can be suitable for applications requiring light delivery deep into living tissue, such as photodynamic therapy.
关键词： optical polymers,biodegradable materials,optical fibers,optical fiber materials,plastic optical fiber
更新于2025-09-12 10:27:22