Laser diode structures which incorporate diffractive features (such as linear gratings or focusing output couplers) have several advantages in terms of device performance and increased flexibility. In this paper the properties of distributed feedback (DFB) and distributed bragg reflector (DBR) laser diodes are compared with those of cleaved cavity fabry-perot type laser diodes. Analysis of the propagation of light in the waveguide formed by the GaAlAs/GaAs/GaAlAs heterostructure will reveal how the interaction of light with periodic variations in dielectric interface can provide the optical feedback neccessary for lasing to occur. The resulting laser light wavelength is significantly less sensitive to the temperature and operating current of the device than that of a cleaved cavity laser diode. A discussion of III-V heterojunctions will allow the investigation of optical waveguiding by layers of differing refractive index and carrier confinement due to different energy gaps in the different layers. The advantages of a multiple quantum well active layer in terms of lowering threshold current and decreasing the sensitivity of output power to temperature will be investigated. Growth techniques for making GaAlAs/GaAs heterostructures using liquid phase epitaxy, chemical vapor deposition and molecular beam epitaxy will be discussed. The procedure for forming diffracting features using either electron beam or holographic exposure of photoresist etch masks is explained. Experimental concerns and configurations for forming holographic etch masks are discussed. Various etching technologies will be reviewed with respect to their ability to transfer submicron features into the substrate. Finally, two surface emitting DFB laser diode structures will be suggested and their fabrication process will be outlined.
Library of Congress Subject Headings
Semiconductor lasers; Diodes, Semiconductor; Gallium arsenide semiconductors
Department, Program, or Center
Electrical Engineering (KGCOE)
Meyers, Mark, "Laser diodes incorporating diffractive features" (1990). Thesis. Rochester Institute of Technology. Accessed from
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