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Structure for Optical Coupling to Thin Semiconductor Layers

IP.com Disclosure Number: IPCOM000076988D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Howard, WE: AUTHOR

Abstract

Heteroepitaxial techniques allow the formation of thin-semiconductor layers having "tailored" properties, including optical properties, and having the additional advantage of being sandwiched between dissimilar semiconductors in such a way that a waveguide structure is formed which confines electromagnetic radiation. This approach has made possible more effective feedback in injection lasers culminating in continuous operation at room temperature.

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Structure for Optical Coupling to Thin Semiconductor Layers

Heteroepitaxial techniques allow the formation of thin-semiconductor layers having "tailored" properties, including optical properties, and having the additional advantage of being sandwiched between dissimilar semiconductors in such a way that a waveguide structure is formed which confines electromagnetic radiation. This approach has made possible more effective feedback in injection lasers culminating in continuous operation at room temperature.

However, to utilize the optical properties of such heterolayers with external light sources for thin layers, the problem of coupling a light beam into the film is encountered.

Such coupling can be facilitated by using the structure of Fig. 1, which is consistent with heteroepitaxial techniques. A substrate A having refractive index lower than the layer of interest, either by bulk property or as a result of previous epitaxy, has deposited onto it a thick layer of the material of interest B. The structure is then lapped at an angle theta which may be typically 1 or 2 degrees. This angle-lapped structure is then used as substrate for the deposition of the thin layer of interest C. Depending upon the experiment, this may or may not be followed by the deposition of a final layer D having a refractive index lower than the layer of interest. (For example, a second layer of material out of which layer A is formed). Fig. 2 shows the resulting structure, with angles and...