Optical modulation by carrier depletion in a silicon PIN diode

Area of Science:

• Optoelectronics
• Semiconductor physics

Background:

• Silicon photonics is crucial for integrated optical circuits.
• Understanding refractive index modulation is key for device performance.

Purpose of the Study:

• To experimentally determine refractive index variations in a silicon PIN diode.
• To differentiate thermal effects from carrier-induced electrical effects.
• To evaluate the device's performance for optical modulation.

Main Methods:

• Fabrication of a silicon PIN diode structure.
• Application of reverse bias voltage to induce carrier depletion.
• Separation of thermal and electrical contributions to refractive index change.
• Optical characterization at 1.55 μm wavelength.
• Numerical simulations for theoretical validation.

Main Results:

• Experimental results for refractive index variation are presented.
• Thermal effects were successfully dissociated from electrical contributions.
• A figure of merit V(π)L(π) of 3.1 V·cm was achieved at 1.55 μm.
• Good agreement was observed between experimental and theoretical index variations.

Conclusions:

• The study provides key experimental data on refractive index modulation in silicon PIN diodes.
• The achieved figure of merit indicates potential for efficient optical modulation.
• The findings support the use of silicon PIN diodes in integrated photonic devices.