Polarization Effects and Design Optimization of InGaN/GaN Coupled Dual Quantum Well Laser for Near-Ultraviolet Emission

III-nitride-based lasers are promising light sources for visible and near-ultraviolet applications, yet their performance is heavily governed by the interplay between material composition and heterostructure design. This paper presents a polarization-enhanced physical modeling framework for InGaN/GaN coupled dual quantum well (DQW) lasers emitting in the 382–394 nm spectral range. The model explicitly accounts for spontaneous and piezoelectric polarization fields, strain effects, and composition-dependent material properties. Optical gain is evaluated via interband transitions between quantized electron and hole states to assess the impact of indium content, quantum well thickness, and barrier design on carrier confinement and inter-well coupling. Simulation results indicate that optimized structures (L w  = 2.0 nm, x _In =12%) can achieve peak optical gain exceeding 360 cm⁻¹ and output powers reaching 8.75 mW at threshold currents of 25.34 mA, while remaining compatible with practical epitaxial growth constraints. These findings provide clear design guidelines for high-performance III-nitride multi-quantum-well laser devices.