| 1. |
- Che, Di, et al.
(författare)
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400-Gb/s direct modulation using a DFB plus R laser
- 2020
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Ingår i: Optics Letters. - : Optical Society of America. - 0146-9592 .- 1539-4794. ; 45:12, s. 3337-3339
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a direct-modulation and direct-detection system with a back-to-back line rate of 411.6 (net bit rate of 337.5) Gb/s using a 65 GHz DFB+R laser. The O-band laser with a chirp parameter of 0.6 supports dispersiontolerant transmissions up to 15 km without an optical amplifier.
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| 2. |
- Gentil, Emmanuel C., et al.
(författare)
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Models for waste life cycle assessment : Review of technical assumptions
- 2010
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 30:12, s. 2636-2648
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Forskningsöversikt (refereegranskat)abstract
- A number of waste life cycle assessment (LCA) models have been gradually developed since the early 1990s, in a number of countries, usually independently from each other. Large discrepancies in results have been observed among different waste LCA models, although it has also been shown that results from different LCA studies can be consistent. This paper is an attempt to identify, review and analyse methodologies and technical assumptions used in various parts of selected waste LCA models. Several criteria were identified, which could have significant impacts on the results, such as the functional unit, system boundaries, waste composition and energy modelling. The modelling assumptions of waste management processes, ranging from collection, transportation, intermediate facilities, recycling, thermal treatment, biological treatment, and landfilling, are obviously critical when comparing waste LCA models. This review infers that some of the differences in waste LCA models are inherent to the time they were developed. It is expected that models developed later, benefit from past modelling assumptions and knowledge and issues. Models developed in different countries furthermore rely on geographic specificities that have an impact on the results of waste LCA models. The review concludes that more effort should be employed to harmonise and validate non-geographic assumptions to strengthen waste LCA modelling.
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| 3. |
- Han, Yong, et al.
(författare)
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Effects of Vehicle Impact Velocity on Pedestrian Fatal Injury Risk
- 2011
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Ingår i: Chinese Journal of Automotive Engineering. - 2095-1469. ; 1:4, s. 399-406, DOI: 10.3969/j.issn.2095-1469.2011.04.020-
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the vehicle speed and vehicle front shape on pedestrian fatal injury risk was investigated. The THUMS pedestrian and four vehicle FE models with different front-ends (medium sedan, minicar, one-box vehicle and SUVs) was used. The pedestrian injury risk was analyzed at speed 20, 30, 40 and 50 km/h. The results demonstrate that the impact speed and vehicle front shape are two important factors influence of the pedestrian kinematics and injuries. A significant reduction of all injuries can be achieved if the impact speed is less than 30 km/h. Head was at high injury risk in medium sedan and SUV collisions. Chest injuries risk was particular high in one-box vehicle impacts. In the minicar collision, the injury risk was the smallest if head without contact to the A-pillar. The design tendency of short front-end and wide windscreen area can be achieved the protection of the pedestrian from fatalities.
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| 4. |
- Kuranaga, Yasuhiro, et al.
(författare)
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Enhancing Detection Sensitivity of ZnO-Based Infrared Plasmonic Sensors Using Capped Dielectric Ga2O3 Layers for Real-Time Monitoring of Biological Interactions
- 2020
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Ingår i: ACS Applied Bio Materials. - : AMER CHEMICAL SOC. - 2576-6422. ; 3:9, s. 6331-6342
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Tidskriftsartikel (refereegranskat)abstract
- Surface plasmon resonances on Ga-doped ZnO (ZnO/Ga) layer surfaces (ZnO-SPRs) have attracted substantial attention as alternative plasmonic materials in the infrared range. We present further enhancement of the detection limits of ZnO-SPRs to monitor biological interactions by introducing thin dielectric layers into ZnO-SPRs, which remarkably modify the electric fields and the corresponding decay lengths on the sensing surfaces. The presence of a high-permittivity dielectric layer of Ga2O3 provides high wavelength sensitivities of the ZnO-SPRs due to the strongly confined electric fields. The superior sensing capabilities of the proposed samples were verified by real-time monitoring of the biological interactions between biotin and streptavidin molecules. Introduction of the high-permittivity dielectric layer into ZnO-SPRs effectively enhances the detection sensitivity and therefore allowed for the observation of biological interactions. This paper provides useful information for the development of optical detection techniques for use in biological fields based on ZnO from the viewpoints of plasmonic applications.
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| 5. |
- Liu, Zhixin, et al.
(författare)
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50-GHz Repetition Gain Switching Using a Cavity-Enhanced DFB Laser Assisted by Optical Injection Locking
- 2020
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 38:7, s. 1844-1850
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate pulse generation at a repetition rate of 50 GHz by gain switching an injection-locked distributed feedback (DFB) laser. The small-signal BW of the DFB laser was enhanced from an intrinsic BW of 30 GHz to 52 GHz due to the joint effects of photon-photon resonance (PPR) and detuned loading. The detuned loading effect is achieved by exploiting the frequency-dependent cavity loss, which results in an increase of the effective differential gain, and correspondingly, the relaxation oscillation frequency. In addition to small-signal measurements, we show that the PPR and the detuned loading effects can also be utilized to improve large signal gain-switching, despite the dynamic changes of the detuned loading condition due to the large signal chirp. By modulating the laser with 50-GHz RF signals, we obtained 50-GHz repetition rate pulses from the gain-switched laser, confirming that the BW enhancement effects are still valid for large-signal modulation. Subsequently, we optically injection lock the gain-switched laser with strong external seeding light, which suppresses the chirp and creates coherent frequency tones with 50 GHz spacing. The optical injection locking (OIL) further enhances the large-signal BW, resulting in narrower pulse width of 9.5 ps (6.2 ps after deconvolution) in the time domain and three sideband peaks above 70% from the peak in the frequency domain (full width half maximum of 130 GHz). Assuming linear chirp, the pulse could be further compressed to 2.4 ps.
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| 6. |
- Matsui, Yasuhiro, et al.
(författare)
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55 GHz Bandwidth Distributed Reflector Laser
- 2017
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Ingår i: Journal of Lightwave Technology. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0733-8724 .- 1558-2213. ; 35:3, s. 397-403
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Tidskriftsartikel (refereegranskat)abstract
- We have demonstrated a 1300-nm short-cavity distributed reflector (DR) laser having 55 GHz bandwidth (BW), and successful 112-Gb/s transmission using four-level pulse-amplitude-modulation (PAM-4), without any pre-equalization for the transmitter. Two effects were realized in the design and operation of the DR laser: photon-photon (P-P) resonance and detuned-loading. The P-P resonance effect was realized between the DFB and distributed Bragg reflector (DBR) modes that coexisted in the cavity of the DR laser. The detuned-loading effect was used to effectively enhance the differential gain through the dynamic change in the mirror reflectivity that occurs on the flank of the DBR mirror due to the frequency chirp under modulation. Despite a limited RC cutoff frequency of 22 GHz, a wide modulation BW of 55 GHz was achieved. It is shown that the RC limitation was counteracted by the combined effects of the detuned-loading, which reduces the damping of relaxation oscillations, and an in-cavity FM-AM conversion effect that created a high-pass filter effect in the modulation response. This will be discussed by way of simulations and experimentally observed eye diagrams for 10 Gb/s NRZ and 28 Gbd PAM-4. The short-cavity DR laser achieved 112-Gb/s PAM-4 transmission over links having a range of dispersions from -28 to +7 ps/nm without precompensation on the transmitter.
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| 7. |
- Matsui, Yasuhiro, et al.
(författare)
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Direct modulation laser technology toward 50-GHz bandwidth
- 2016
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Ingår i: 2016 INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE (ISLC). - : IEEE. - 9784885523069
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Konferensbidrag (refereegranskat)abstract
- A short cavity distributed reflector (DR) laser with a modulation bandwidth of 55GHz was developed using the photon-photon resonance and detuned-loading effects. The importance of the chirp parameter for the speed enhancement is discussed.
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| 8. |
- Matsui, Yasuhiro, et al.
(författare)
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Direct Modulation Lasers for High-speed Data Communication Systems
- 2022
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Ingår i: OECC/PSC 2022. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- This paper reviews the high-speed directly modulated laser physics known for a long while yet recently have regained attention to realize a bandwidth reaching to 100 GHz. Chirp-managed laser for reach extension is also discussed.
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| 9. |
- Matsui, Yasuhiro, et al.
(författare)
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Low-chirp isolator-free 65-GHz-bandwidth directly modulated lasers
- 2021
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Ingår i: Nature Photonics. - : Springer Nature. - 1749-4885 .- 1749-4893. ; 15:1, s. 59-63
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Tidskriftsartikel (refereegranskat)abstract
- Today, in the face of ever increasing communication traffic, minimizing power consumption in data communication systems has become a challenge. Direct modulation of lasers, a technique as old as lasers themselves, is known for its high energy efficiency and low cost. However, the modulation bandwidth of directly modulated lasers has fallen behind those of external modulators. In this Article, we report wide bandwidths of 65-75 GHz for three directly modulated laser design implementations, by exploiting three bandwidth enhancement effects: detuned loading, photon-photon resonance and in-cavity frequency modulation-amplitude modulation conversion. Substantial reduction of chirp (alpha < 1.0) as well as isolator-free operation under a reflection of up to 40% are also realized. A fast data transmission of 294.7 Gb s(-1) over15 km of a standard single-mode fibre in the O-band is demonstrated. This was achieved without an optical fibre amplifier due to a high laser output power of 13.6 dBm.
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| 10. |
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