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https://ptsldigital.ukm.my/jspui/handle/123456789/486953Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Ahmad Ashrif Abu Bakar, Assoc. Prof. Ir. Dr. | - |
| dc.contributor.author | Musab Ahmad Mohammad Al-Tarawni (P73306) | - |
| dc.date.accessioned | 2023-10-11T02:26:54Z | - |
| dc.date.available | 2023-10-11T02:26:54Z | - |
| dc.date.issued | 2018-08-31 | - |
| dc.identifier.other | ukmvital:118694 | - |
| dc.identifier.uri | https://ptsldigital.ukm.my/jspui/handle/123456789/486953 | - |
| dc.description | Integrated optical waveguide modulators (IOWMs) are essential elements in modern electric (E)-field sensors owing to their compact size, high sensitivity, and robustness over conventional electronic sensors. In such sensors, improving sensitivity and expanding the limit of detection (LOD) mainly rely on achieving a low half-voltage, Vπ, by enhancing waveguide materials with a high electro-optic coefficient, r33. Detecting low AC E-fields through the IOWM technology required significantly low Vπ. Nevertheless, using a high r33 to reduce Vπ causes high thermal instability, limiting the sensor's operational lifetime. Designing waveguides with low r33 for lowfrequency AC E-fields is challenging because Vπ is magnified, limiting sensor sensitivity to small AC E-field signals and distorting the low-frequency signal. This work aims to investigate the effect of improving overlap integral factor, Г, for rib, segmented slot waveguide (SSW), and hybrid segmented slot waveguide (HSSW) on Vπ, modulation efficiency, sensitivity, and expand the LOD of the sensor AC E-field. The polymer rib waveguide, followed by SSW, which is based on a Si organic hybrid (SOH), was used as the core of the IOWM. HSSW is proposed; in this waveguide design, a thin Si-layer is added beneath an SSW to limit high reflection in the SSW and improve the confinement factor and effective nonlinear area (Aeff), thus enhancing Г of the IOWM. In addition, the effect of increasing environmental temperature on the sensitivity error, S_error, of the AC E-field sensor based on the waveguide structures was analyzed. Theoretical and modelling analyses were performed to test the effect of the rib, SSW, and HSSW dimensions on the performance of the IOWM and the sensor. The AC E-field sensor was optimized based on the rib waveguide due to the variation of the total waveguide thickness (TWG). Periodicities, segment width, and Silayer thickness were optimized for SSW and HSSW, and were used to completely characterize the sensor's Vπ, modulator efficiency, and sensitivity. The results showed that reducing TWG resulted in approximately 23% high Г; furthermore, using small TWG with 30 pm/V resulted in lowest Vπ, and Vπ.L to 2.2 V and 3.1 V.cm, respectively compared with different rib waveguide thickness. The AC E-field sensor based on the rib waveguide that used 30 pm/V with small TWG was able to detect minimum E-field signal at around 45 V/m with 62.9 dB sensitivity. However, the highest thermal stability of the sensor was found when using small TWG with low r33, which was indicated by the lowest S_error of approximately -0.01594 dB/1 °C. On the other hand, reduction of the SSW's segment width and periodicity increased Г to 25% and decreased Vπ to 0.32 V, with a small electrical bandwidth of 4.3 kHz. The SSW showed a low S_error approximately 0.01763 dB/1 °C. HSSW with 20 nm Si-layer at 400 nm periodicity showed reduced segment width increased Г to 31%, while the minimum detected E-field, sensitivity, and S_error were 7.5 V/m, 63.1 dB, and 0.026358 dB/1°C respectively. Thicker Si-layers can effectively enhance the sensitivity around 62.9 dB due to high Г (26%). The HSSW with 40 nm Si-layer showed high S_error approximately 0.033049 dB/1°C, which was most thermally unstable compared to the SSW and HSSW with different thicknesses. This study also demonstrates the impact and efficiency of using rib, SSW, and HSSW waveguides for AC E-field sensors.,Ph.D. | - |
| dc.language.iso | eng | - |
| dc.publisher | UKM, Bangi | - |
| dc.relation | Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina | - |
| dc.rights | UKM | - |
| dc.subject | Integrated optics | - |
| dc.subject | Optical wave guides | - |
| dc.subject | Universiti Kebangsaan Malaysia -- Dissertations | - |
| dc.subject | Dissertations, Academic -- Malaysia | - |
| dc.title | Integrated optical waveguide modulator for electric field sensors | - |
| dc.type | Theses | - |
| dc.format.pages | 266 | - |
| dc.identifier.callno | TA1800.T347 2018 3 tesis | - |
| dc.identifier.barcode | 004027(2019) | - |
| Appears in Collections: | Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina | |
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| File | Description | Size | Format | |
|---|---|---|---|---|
| ukmvital_118694+SOURCE1+SOURCE1.0.PDF Restricted Access | 6.6 MB | Adobe PDF |  View/Open |
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