Iet Optoelectronics最新文献

{"title":"VCSEL quick fabrication of 894.6 nm wavelength epi-material for miniature atomic clock applications","authors":"Jack Baker,&nbsp;Craig. P. Allford,&nbsp;Sara. Gillgrass,&nbsp;Tomas. Peach,&nbsp;James Meiklejohn,&nbsp;Curtis Hentschel,&nbsp;Wyn Meredith,&nbsp;Denise Powell,&nbsp;Tracy Sweet,&nbsp;Mohsin Haji,&nbsp;J. Iwan Davies,&nbsp;Samuel Shutts,&nbsp;Peter M. Smowton","doi":"10.1049/ote2.12082","DOIUrl":"10.1049/ote2.12082","url":null,"abstract":"A vertical cavity surface emitting laser (VCSEL) quick fabrication (VQF) process is applied to epitaxial materials designed for miniature atomic clock applications (MACs). The process is used to assess material quality and uniformity of a full 100 mm (4 ‐ inch) wafer against the stringent target specification of VCSELs for MACs. Target specifications in optical power ( > 0.6 mW) and differential efficiencies ( < 0.5 W/A) are achieved over large portions of a wafer; however, the variation in the oxide aperture diameter is shown to limit the yield. The emission of the fundamental mode","PeriodicalId":13408,"journal":{"name":"Iet Optoelectronics","volume":"17 1","pages":"24-31"},"PeriodicalIF":1.6,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/ote2.12082","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41588626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding and evaluating the mean photon energy and the external quantum efficiency of light-emitting diodes","authors":"Ilgyu Choi,&nbsp;Sangjin Min,&nbsp;Jong-In Shim,&nbsp;Dong-Soo Shin","doi":"10.1049/ote2.12083","DOIUrl":"10.1049/ote2.12083","url":null,"abstract":"<p>The mean photon energy of a light-emitting diode (LED) as recently defined in the IEC standard is theoretically examined. It is pointed out that defining the mean photon energy as an arithmetic mean of photon energies in the emission spectrum is crucial in decomposing the power efficiency of an LED into the voltage efficiency and the external quantum efficiency (EQE). The mean photon energy thus defined and the photon energy calculated from the more convenient peak wavelength in the spectrum are then evaluated and compared for blue and red LED samples. The EQEs of the blue and red LEDs are subsequently obtained, demonstrating that the EQE values from the peak photon energy have small errors within 0.5%p of the true EQE values. The current work presents useful criteria in substituting the EQE value calculated from the peak wavelength for the true EQE value using the mean photon energy for both the blue and red LEDs.</p>","PeriodicalId":13408,"journal":{"name":"Iet Optoelectronics","volume":"17 1","pages":"32-37"},"PeriodicalIF":1.6,"publicationDate":"2022-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/ote2.12083","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43512778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probe pulse design in Brillouin optical time-domain reflectometry","authors":"Mupeng Li,&nbsp;Tianhua Xu,&nbsp;Shuang Wang,&nbsp;Wenxiu Hu,&nbsp;Junfeng Jiang,&nbsp;Tiegen Liu","doi":"10.1049/ote2.12081","DOIUrl":"10.1049/ote2.12081","url":null,"abstract":"<p>Brillouin optical time-domain reflectometry (BOTDR) is a branch of distributed fibre-optic sensors, and it can measure the strain and the temperature information, localised by the return time of the probe pulse, along the fibre based on the spontaneous Brillouin scattering process. Parameters of the BOTDR system, including the spatial resolution, the signal-to-noise ratio, the measurement speed, and the sensing range, have a mutually restrictive relationship. In order to improve the performance of the BOTDR system, researchers have focussed on improving the design of the probe pulse, for example, transforming the shape, the sequence, and the spectral properties of the pulse. This study summarises the recent progress in the design of detection pulses in BOTDR systems, and comprehensively demonstrates the improvement effects of various pulse modulation formats on the system performance.</p>","PeriodicalId":13408,"journal":{"name":"Iet Optoelectronics","volume":"16 6","pages":"238-252"},"PeriodicalIF":1.6,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/ote2.12081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41424907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Special issue “optical communications, sensing, and laser applications”","authors":"Ming Tang,&nbsp;Zhenzhou Cheng,&nbsp;Liang Wang,&nbsp;Li Shen","doi":"10.1049/ote2.12080","DOIUrl":"10.1049/ote2.12080","url":null,"abstract":"&lt;p&gt;This Special Issue highlights topics relating to recent research advances in optical communications, optical sensing and laser applications, emphasising fibre-optic communication systems/sub-systems; optical signal processing; optical fibre sensors and devices; and various applications of silicon photonics, modulators, and optoelectronic integration circuits. It brings together contributions by outstanding international leaders, researchers, scientists, and engineers from a broad range of interdisciplinary fields to present their work in the science, technology, and applications of optical communications, optical sensing, and related laser techniques.&lt;/p&gt;&lt;p&gt;In this Special Issue, we have accepted five papers, which can be clustered into two main categories, namely optical communications and optical sensing. The papers falling into the first category exhibit novelties in optical switches and modulators. The papers in this category are from Zhentian Shan et al. and Yue Wu et al. The second category of papers offers direct solutions to optical sensing with applications to environmental and biomedical monitoring. These papers are from Mupeng Li et al., Majid Mafi et al., and Ying Zhang et al. A brief presentation of each paper in this special issue is as follows:&lt;/p&gt;&lt;p&gt;Zhentian Shan et al. report a 1*48 large-scale multi-mode fibre optical switch driven by a stepper motor. The insertion loss is &lt;1.42 dB, which can be further reduced to 1.02 dB after optimisation. With the employment of a corner cube prism in the optics, the device is characterised by good repeatability of &lt;±0.01 dB. The device has a fast response of &lt;8 ms.&lt;/p&gt;&lt;p&gt;Yue Wu et al. present a new doping profile of the PN depletion region with four doping concentration levels for Microring modulator (MRM) considering the electrical bandwidth. By increasing the electrical bandwidth, the electro-optical (EO) bandwidth is increased. The MRM is characterised and is applied in a WDM transmitter. By the measurement, the transmitter with the designed MRM could transmit PAM4 signal at 52 Gbps rate, which indicates the MRM could be potential for the 50 Gbps/ch optical interconnection.&lt;/p&gt;&lt;p&gt;Mupeng Li et al. give a review on Brillouin optical time-domain reflectometry (BOTDR), which is a branch of distributed fibre-optic sensing, and can measure the strain and temperature information. This paper summarises the recent progress in the design of detection pulses in BOTDR systems and comprehensively demonstrates the improvement effects of various pulse modulation formats on the system performance.&lt;/p&gt;&lt;p&gt;Majid Mafi et al. investigate a high-quality and multi-purposed biosensor with maximum stable output transmittance numerically by using the inverse design method. The proposed biosensor utilises particle swarm optimisation for inverse design, which will be a helpful way of designing different kinds of precise sensors in the future. The proposed sensor can sense different parts of blood componen","PeriodicalId":13408,"journal":{"name":"Iet Optoelectronics","volume":"16 6","pages":"235-237"},"PeriodicalIF":1.6,"publicationDate":"2022-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/ote2.12080","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42288099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimal power allocation in serial relay-assisted underwater wireless optical communication systems","authors":"Hamed Rabbani,&nbsp;S. Alireza Nezamalhosseini,&nbsp;Lawrence R. Chen,&nbsp;AliAsghar Beheshti-Shirazi","doi":"10.1049/ote2.12079","DOIUrl":"10.1049/ote2.12079","url":null,"abstract":"<p>For a serial relaying underwater wireless optical communication (UWOC) system with ON-OFF keying modulation, we theoretically evaluate the optimal power allocation techniques in order to minimise the end-to-end bit error rate (BER), subject to transmission power constraints. At first, we evaluate the end-to-end BER with respect to all degrading effects of the UWOC channel, namely scattering, absorption, and turbulence-induced fading and then develop a closed-form BER expression as a function of transceiver parameters and water type. The optimal power allocation methods are obtained using the perfect channel state information available at the receiver (CSIR) and transmitter (CSIT) for both detect-and-forward (DF) and amplify-and-forward (AF) serial relaying systems. For each relaying method, we consider a dual-hop UWOC system and determine optimal power allocation to minimise the BER. Afterwards, the optimal power allocation in a multi-hop system is obtained to minimise the end-to-end BER. Compared to the equal power allocation, our results illustrate that UWOC relaying systems with optimal power allocation can significantly improve the end-to-end BER and expand the communication link. For instance, the proposed power allocation method for the DF and AF relay node in a 60 m single relay system improves the system performance at the BER of 10⁻⁵ by 2.5 and 1.8 dB compared to the equal power allocation, respectively.</p>","PeriodicalId":13408,"journal":{"name":"Iet Optoelectronics","volume":"17 1","pages":"12-23"},"PeriodicalIF":1.6,"publicationDate":"2022-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/ote2.12079","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44548792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical gas sensing of sub-ppm SO2F2 and SOF2 from SF6 decomposition based on photoacoustic spectroscopy","authors":"Ying Zhang,&nbsp;Mingwei Wang,&nbsp;Pengcheng Yu,&nbsp;Zhe Liu","doi":"10.1049/ote2.12077","DOIUrl":"10.1049/ote2.12077","url":null,"abstract":"<p>SF₆ has been recognized worldwide as the main insulating gas for Gas-Insulated Switchgear (GIS). It is often required to accurately and effectively detect typical SF₆ decomposition. In this paper, a sub-ppm-level SO₂F₂ and SOF₂ gas sensor based on photoacoustic spectroscopy (PAS) is proposed and demonstrated. The steel resonant photoacoustic cell with a resonant frequency of 1750 Hz was designed and fabricated. The harmonic detection technique in wavelength modulation spectroscopy was applied to improve the signal-to-noise ratio. A mercury-cadmium-telluride photodetector was added in the PAS system to monitor the input optical power, in order to compensate for the errors caused by power fluctuations. SO₂F₂ and SOF₂ were measured by using distributed feedback quantum cascade lasers at 6648 and 7463 nm, respectively. The results show that the proposed sensor performed with favourable linearity within the dynamic range, and reached the minimum detection limit of 0.22 ppm for SO₂F₂ and 0.28 ppm for SOF₂, which indicated its great potential for monitoring the decomposition process of SF₆ in GIS.</p>","PeriodicalId":13408,"journal":{"name":"Iet Optoelectronics","volume":"16 6","pages":"277-282"},"PeriodicalIF":1.6,"publicationDate":"2022-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/ote2.12077","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49097039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A 1 × 48 large-scale multi-mode fibre optical switch","authors":"Zhentian Shan,&nbsp;Zhujun Wan,&nbsp;Zhixiang Luo","doi":"10.1049/ote2.12076","DOIUrl":"10.1049/ote2.12076","url":null,"abstract":"<p>A 1 × 48 large-scale multi-mode fibre (MMF) optical switch driven by a stepper motor is reported. The insertion loss is &lt;1.42 dB, which can be further reduced to 1.02 dB after optimisation. With the employment of a corner cube prism in the optics, the device is characterised by good repeatability of &lt;±0.01 dB. Meanwhile, the device has a fast response of &lt;8 ms.</p>","PeriodicalId":13408,"journal":{"name":"Iet Optoelectronics","volume":"16 6","pages":"253-256"},"PeriodicalIF":1.6,"publicationDate":"2022-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/ote2.12076","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48519458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Curvature prediction of long-period fibre grating based on random forest regression","authors":"Xingliu Hu,&nbsp;Haifei Si,&nbsp;Quanyi Ye,&nbsp;Yan Zhang","doi":"10.1049/ote2.12078","DOIUrl":"10.1049/ote2.12078","url":null,"abstract":"<p>This study proposes a long-period fibre grating (LPFG) curvature estimation method based on random forest regression (RFR) to address the shortcomings of the existing curvature evaluation method, namely, polynomial fitting; these shortcomings cause difficulty in achieving adequate model regularity and application universality. The resonant wavelength and resonant peak amplitude of the LPFG are used as input variables in this method to develop an RFR model for curvature estimation, allowing for accurate curvature prediction of the sample. The results show that the RFR-based LPFG curvature prediction model can better characterise the input–output regression relationship than back-propagation neural networks. The average R² value of the RFR model is 0.9826, and the actual measured curvature value is highly correlated with the model predicted curvature value. Compared to that exhibited by back-propagation neural networks, the RFR model exhibits higher accuracy for curvature estimation, with average values of 0.1314 and 0.1173 for root mean square and mean absolute errors, respectively. This method can provide a more comprehensive theoretical basis for the application of robot learning in the curvature measurement of LPFG and has practical value.</p>","PeriodicalId":13408,"journal":{"name":"Iet Optoelectronics","volume":"16 5","pages":"225-233"},"PeriodicalIF":1.6,"publicationDate":"2022-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/ote2.12078","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43193722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new complexity reduction scheme in selective mapping-based visible light communication direct current-biased optical orthogonal frequency division multiplexing systems","authors":"Chakravarthy Gunturu,&nbsp;Sivaprasad Valluri","doi":"10.1049/ote2.12074","DOIUrl":"10.1049/ote2.12074","url":null,"abstract":"<p>Visible light communication (VLC) has emerged as a good accompaniment to radio-frequency (RF) technologies by deploying multicarrier schemes such as orthogonal frequency division multiplexing (OFDM). However, the coherent summation of carriers in the OFDM system leads to a high peak-to-average-power ratio (PAPR), causing non-linear clipping distortion at the transmitting light-emitting diode. This intricacy becomes a potential barrier for intensity modulation and limits the VLC systems' bandwidth. In the literature, non-distorting PAPR lowering approaches, such as the selective mapping (SLM) approach, have been confirmed as the most effective strategy for reducing ineludible high PAPR in optical OFDM systems among all other available techniques. Besides its astounding performance, the computational complexity also becomes a major complication in SLM due to the generation of multiple candidates. This paper proposes a computational complexity minimisation approach using inherit system properties in the SLM-based PAPR suppression method for VLC systems, where the phase sequence vectors are considered periodic. The alternative direct current-biased optical orthogonal frequency division multiplexing candidates for the single frequency-domain data block are generated with the periodic phase rotation vector. The evaluation of the complexity analysis and the simulation results shows that the mitigation of computational complexity surpasses the standard SLM technique.</p>","PeriodicalId":13408,"journal":{"name":"Iet Optoelectronics","volume":"16 5","pages":"207-217"},"PeriodicalIF":1.6,"publicationDate":"2022-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/ote2.12074","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44295946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Self-starting generation of tri-band frequencies using a dual-parallel Mach–Zehnder modulator-based optoelectronic oscillator","authors":"Quanjing Zhao,&nbsp;Juanjuan Yan","doi":"10.1049/ote2.12075","DOIUrl":"10.1049/ote2.12075","url":null,"abstract":"<p>A scheme for multi-band frequency generation is proposed and experimentally demonstrated using a dual-parallel Mach–Zehnder modulator (DPMZM)-based optoelectronic oscillator (OEO). The principle of this generator is theoretically described in detail. It is found that multiple frequencies with a small power variation can be produced by setting the three working points and the modulation depth of the DPMZM. In the proving experiment, an 8-GHz fundamental oscillation with a side mode suppression ratio of 44 dB is generated. The phase noise is measured to be −96.8 dBc/Hz @ 10 KHz offset with a 100-m and 1-Km optical fibre used in the two oscillation loops. When the oscillating signal is applied to drive the two sub-modulators in the DPMZM, doubled and tripled frequencies are produced at the same time, and the phase noises of the two frequencies are also measured to be −90.2 dBc/Hz and −85.9 dBc/Hz @10 KHz, respectively.</p>","PeriodicalId":13408,"journal":{"name":"Iet Optoelectronics","volume":"16 5","pages":"218-224"},"PeriodicalIF":1.6,"publicationDate":"2022-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/ote2.12075","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47135198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}