1. Silicon photonics vs. Traditional semiconductor chips: Scientists from the US and Europe have fabricated the first miniaturised lasers directly on silicon wafers.

• This marks a major advance in silicon photonics, boosting computing performance and energy efficiency.
• About: Silicon photonics is a technology that combines the principles of photonics (using light for information transmission) with the advantages of silicon-based microchip fabrication.

o Applications: Data centres, sensors, and quantum computing.

o Photon advantages: Faster data transfer, higher capacity, and lower energy loss.

o Photonic Chip Components: Source (electrons/photons) → Waveguides (photon paths) → Modulators (encode/decode data) → Photodetectors (light to electricity).

• Laser: Hardest component to integrate due to material limitations.
• How Lasers Work

o Laser principle: Based on stimulated emission, creating a coherent light beam.

o Silicon drawback: Has an indirect bandgap, poor for light emission.

o Common materials: Gallium arsenide (direct bandgap) enables efficient light emission.

• About Semiconductor Chips:

o Semiconductors are materials that exhibit a conductivity level between conductors and insulators. They can be pure elements such as silicon or compounds like gallium arsenide.