Silicon Laser. Shyam Sabanathan Chenjing Li Thannirmalai. Silicon and its properties. It is semiconductor which is used in most of the electronic devices. It is found abundant in nature.
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Hybrid Silicon Laser
Hybrid Silicon Laser Demonstration
Unlike the III-V compounds, such as gallium arsenide, generally used to make semiconductor lasers, silicon has an indirect bandgap. That means the momentum of the charge carriers—negative electrons and positive holes—do not match, and when they combine they are more likely to produce a vibration than a photon.
Intel researchers used an external light source to "pump" light into their chip. The natural atomic vibrations in silicon amplify the light as it passes through the chip. This amplification is called the Raman effect.
But, increasing the light pump power beyond a certain point no longer increased amplification and eventually even decreased it. The reason was a physical process called "Two-Photon Absorption" .
To integrate a semiconductor structure, PIN (P-type - Intrinsic - N-type) device into the waveguide. When a voltage is applied to the PIN, it acts like a vacuum and removes most of the excess electrons from the light's path. The PIN device combined with the Raman effect produces a continuous laser beam.