SLIPT Power Splitting and Energy Harvesting

1. Light as Energy

The receiver in SLIPT/VLC receives visible light from an LED or laser source. Light carries photons which have energy:

E_photon = h f

Where h is Planck's constant and f is the light frequency. More light power means more energy is available.

2. Photovoltaic Effect (Energy Harvesting)

The receiver has a solar-cell-like or photodiode circuit that converts light into electricity:

• Light hits the photodiode.
• Photons excite electrons in the semiconductor material.
• Electrons flow as DC current → can charge a battery or capacitor.

3. AC/DC Split

The received light signal contains two components:

• AC component: contains information (modulated data).
• DC component: contains average power, which can be converted to energy.

The power-splitting circuit divides the light power fraction β:

P_EH = β P_total,    P_ID = (1−β) P_total

P_EH → feeds the energy harvesting circuit (DC),
P_ID → feeds the information decoding circuit (AC).

4. Analogy

Imagine a water pipe representing the light beam and two buckets:

• Bucket 1 (EH) gets β fraction of water → harvest energy.
• Bucket 2 (ID) gets 1-β fraction of water → decode data.

5. Practical Example

Received light power: Ptotal = 10 mW
Power splitting: β = 0.6

P_EH = 0.6 × 10 = 6 mW   (harvested energy)

P_ID = 0.4 × 10 = 4 mW   (used for decoding data)

The photodiode converts the 6 mW into DC electricity to charge a battery or capacitor.

6. Summary

The light itself contains energy. The receiver uses a photodiode or solar-cell circuit to convert part of that light into electrical energy. The power-splitting factor β controls how much of the light goes to energy harvesting versus information decoding.

Further Reading

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