Effect of Ridge Width on the Lasing Characteristics of Triangular and Rectangular InAs/In0.53Ga0.47As Quantum Well Lasers

The lasing characteristics of InP-based InAs/In0.53Ga0.47As quantum well (QW) lasers with different ridge widths are investigated. Two groups of lasers are grown for comparison, one with active triangular QW regions and the other with rectangular QW regions. Their output powers, characteristic temperatures (T0), external differential quantum efficiencies (ηd) and junction temperatures (Tj) are analyzed and compared. The parameter of ridge width is found to play an important role in the performance of the lasers. In triangular QW lasers, by broadening the ridge width from 8 to 12\ua0μm, output power and ηd of the lasers are decreased for the temperature range of 100–320\ua0K due to heating effect. But by broadening the ridge width from 8 to 100\ua0μm in rectangular QW lasers, output power has about 3.5 time increase at 100\ua0K and ηd also has a little increase for temperatures from 100 to 180\ua0K due to much larger emission area and much faster heat dissipation. Tj, the real temperature of the active region, is also found to have accelerated increase at high injection current and heat sink temperature. Besides, compared to the rectangular QW laser of the same ridge width, the improved thermal performance of triangular QW laser is also demonstrated

Risk Assessment of Distribution Lines in Typhoon Weather Considering Socio-economic Factors

In recent years, the frequent occurrence of typhoon weather has posed a significant threat to the stable operation of the distribution network in the southeastern coastal areas of China. Ensuring the safety of distribution lines is crucial for the normal functioning of the distribution network. Therefore, this paper proposes a risk assessment method for distribution lines in typhoon weather. Firstly, the risk assessment system for distribution lines is constructed by considering three perspectives: line structure, line state, and social economic factors. Secondly, the weight of each evaluation index is calculated using the analytic hierarchy process and CRITIC weight method. The cooperative game method is then employed to combine the calculation results, and the results are further optimized using variable weight theory. Finally, a cloud model-based risk assessment model for distribution lines is established. The analysis and calculation of distribution network data in a specific area indicate that the risk assessment level, which takes into account social and economic factors, is more accurate compared to other methods discussed in this paper. It is observed that the multi-model approach yields higher accuracy than the single-model approach. Therefore, the proposed method holds significant reference value for evaluating the risk level of distribution lines

Media 5: Generation of dipole vortex array using spiral Dammann zone plates

Originally published in Applied Optics on 01 October 2012 (ao-51-28-6799

Media 3: Generation of dipole vortex array using spiral Dammann zone plates

Originally published in Applied Optics on 01 October 2012 (ao-51-28-6799

Media 2: Generation of dipole vortex array using spiral Dammann zone plates

Originally published in Applied Optics on 01 October 2012 (ao-51-28-6799

Media 6: Generation of dipole vortex array using spiral Dammann zone plates

Originally published in Applied Optics on 01 October 2012 (ao-51-28-6799

Media 1: Distorted Dammann grating

Originally published in Optics Letters on 15 February 2013 (ol-38-4-474

Media 1: Generation of dipole vortex array using spiral Dammann zone plates

Originally published in Applied Optics on 01 October 2012 (ao-51-28-6799

Media 4: Generation of dipole vortex array using spiral Dammann zone plates

Originally published in Applied Optics on 01 October 2012 (ao-51-28-6799