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Full-Text Articles in Engineering
Stress-Induced Birefringence And Fabrication Of In-Fiber Polarization Devices By Controlled Femtosecond Laser Irradiations, Lei Yuan, Baokai Cheng, Jie Huang, Jie Liu, Hanzheng Wang, Xinwei Lan, Hai Xiao
Stress-Induced Birefringence And Fabrication Of In-Fiber Polarization Devices By Controlled Femtosecond Laser Irradiations, Lei Yuan, Baokai Cheng, Jie Huang, Jie Liu, Hanzheng Wang, Xinwei Lan, Hai Xiao
Electrical and Computer Engineering Faculty Research & Creative Works
Optical birefringence was created in a single-mode fiber by introducing a series of symmetric cuboid stress rods on both sides of the fiber core along the fiber axis using a femtosecond laser. The stress-induced birefringence was estimated to be 2.4 x 10-4 at the wavelength of 1550 nm. By adding the desired numbers of stressed rods, an in-fiber quarter waveplate was fabricated with a insertion loss of 0.19 dB. The stressinduced birefringence was further explored to fabricate in-fiber polarizers based on the polarization-dependent long-period fiber grating (LPFG) structure. A polarization extinction ratio of more than 20 dB was observed …
Beyond Conventional C-Plane Gan-Based Light Emitting Diodes: A Systematic Exploration Of Leds On Semi-Polar Orientations, Morteza Monavarian
Beyond Conventional C-Plane Gan-Based Light Emitting Diodes: A Systematic Exploration Of Leds On Semi-Polar Orientations, Morteza Monavarian
Theses and Dissertations
Despite enormous efforts and investments, the efficiency of InGaN-based green and yellow-green light emitters remains relatively low, and that limits progress in developing full color display, laser diodes, and bright light sources for general lighting. The low efficiency of light emitting devices in the green-to-yellow spectral range, also known as the “Green Gap”, is considered a global concern in the LED industry. The polar c-plane orientation of GaN, which is the mainstay in the LED industry, suffers from polarization-induced separation of electrons and hole wavefunctions (also known as the “quantum confined Stark effect”) and low indium incorporation efficiency that …