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Description
The project addresses the unsolved question about production technology of single-frequency semiconductor lasers emitting in visible range λ=380-530 nm. Stable single wavelength operation
with high side mode suppression ratio is required for such applications as: high-speed, last-mile communication based on plastic optical fibers, precise time measurements by atomic clocks or
advanced sensors based on interferometry. The III-nitride material family offers a high promise to fill the niche existing on the market. The reason why the nitride DFB LDs are not yet available
on the market is because of severe limitations related to inherent material properties of (In,Al,Ga)N alloys, namely: low refractive index contrast and high lattice mismatch. A few concepts to
address these issue have been reported, utilizing a photonic grating on top of LD structure. Project PI, Marta Sawicka, based on her earlier work on electrochemical etching of GaN:Si, proposes
a novel approach, namely introduction of photonic grating buried inside the LD for high coupling with optical mode. A periodic array of nanometer size air-channels inside GaN will be formed in
order to locally obtain a very high refractive index contrast. The goal of the project is to develop a combination of two technologies: ion implantation and electrochemical etching in order to
fabricate buried photonic structure (air-GaN grating) that could be located below the active region of the device. Such air-GaN grating will be integrated in a blue LD structure grown by plasmaassisted
molecular beam epitaxy in order to demonstrate novel design nitride DFB LD. Performance of such development will be investigated theoretically and characterized experimentally in
order to verify the applicability of the proposed invention.