A comparison between two heterodyne light sources using different electro-optic modulators for optical temperature...

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Interferometry

Background:

• Electro-optic modulators are crucial components in optical sensing systems.
• Lithium niobate (LiNbO3) is a widely used material for electro-optic devices.
• Photorefractive effects can impact modulator performance, especially at shorter wavelengths.

Purpose of the Study:

• To demonstrate a z-propagating Zn-indiffused lithium niobate waveguide electro-optic modulator.
• To evaluate its performance in optical heterodyne interferometry and optical temperature sensing.
• To compare its characteristics with a commercial buck-type electro-optic modulator.

Main Methods:

• Fabrication of a Zn-indiffused lithium niobate waveguide modulator.
• Utilizing optical heterodyne interferometry for phase measurement.
• Implementing an optical temperature measurement system with the modulator.
• Testing performance at visible wavelengths (532 nm and 632.8 nm).

Main Results:

• The homemade waveguide modulator exhibited lower driving voltage and smaller phase variation than a commercial buck-type modulator.
• Both modulators showed similar temperature sensitivities (25 deg/°C) at 632.8 nm.
• At 532 nm, the homemade modulator achieved higher sensitivity (30 deg/°C) and resolution (0.07 °C) due to stable operation, unlike the buck-type modulator affected by photorefractive impacts.

Conclusions:

• Zn-indiffused lithium niobate waveguide modulators are effective for optical heterodyne interferometry and temperature sensing.
• The proposed modulator offers advantages in driving voltage, phase stability, and measurement accuracy, particularly at 532 nm.
• This technology shows potential for improved optical sensing applications where photorefractive effects are a concern.