Key Points
- Improve homojunction semiconductor laser by use of
multiple material devices -- hetrojunction. Usually, In-P-Ga-As.
- Band structure engineering to confine carriers to an
active region.
- Control of the index of refraction to provide wave
guiding, due to total internal reflection.
- Geometric confinement to create a "stripe" laser.
- Wavelength control by controlling the length of the
cavity or by use of diffraction elements.
Questions
- How to make a better laser?
- How can we control the wavelength of the laser?
- What materials are use to make hetrojunction lasers and
why?