Grating coupled surface emitting device
AssigneeKabushiki Kaisha Toshiba
InventorsYuzo Hirayama, Masahisa Funemizu, Masaki Tohyama, Motoyasu Morinaga, Keiji Takaoka, Kazuhiro Inoue, Makoto Ohashi
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Abstract
A grating coupled surface emitting laser has a diffraction grating of a second or higher order for guided-mode light part of a waveguide region, and extract a beam in a direction perpendicular to the waveguide region. By narrowing a stripe of the waveguide region around the center, the phase of the diffraction grating is shifted to attain a Gaussian distribution for radiation-mode light in a cross section along the waveguiding direction.
Claims21
A grating coupled surface emitting device comprising:
- a semiconductor active layer;
- first and second semiconductor layers of first and second conductivity types arranged to interpose said active layer therebetween;
- first and second electrodes respectively connected to said first and second semiconductor layers;
- a waveguide configured to form guided-mode light having forward and backward wave components from light emitted from said active layer;
- a diffraction grating which is arranged in said waveguide and has an order not less than a second order for the guided-mode light, the guided-mode light being output as radiation-mode light in a direction perpendicular to said waveguide by said diffraction grating from an optical output portion;
- and
- a phase shifter configured to shift a phase of said diffraction grating, said phase shifter being arranged in a substantially symmetrical distribution shape over a distance larger than a period of said diffraction grating so as to bring the forward and backward wave components of the guided-mode light into interference to strengthen each other at a central portion of the radiation-mode light in outputting the forward and backward wave components as the radiation-mode light, and to bring the forward and backward wave components into interference to weaken each other at portions on two sides of the radiation-mode light, thereby attaining a Gaussian distribution for the radiation-mode light.
A grating coupled surface emitting device comprising:
- a semiconductor active layer;
- first and second semiconductor layers of first and second conductivity types arranged to interpose said active layer therebetween;
- first and second electrodes respectively connected to said first and second semiconductor layers;
- a waveguide configured to form guided-mode light having forward and backward wave components from light emitted from said active layer;
- and
- a diffraction grating which is arranged in said waveguide and has an order not less than a second order for the guided-mode light, the guided-mode light being output as radiation-mode light in a direction perpendicular to said waveguide by said diffraction grating from an optical output portion,
- wherein a region corresponding to said optical output portion in said waveguide has an absorption edge wavelength shorter than those of regions on two sides.
Dependencies are inferred from the claim text.