Physics Lab Equipment

     LEOI-34 Experimental System for Electro-Optic Modulation.png

Schematic of transverse electro-optic modulation

S: Source laser         P: Polarizer

C: LiNbO3 crystal     A: Analyzer

V: Voltage                 D: Photo receiver

     Experimental System for Electro-Optic Modulation.png

Schematic of experimental configuration

1. He-Ne laser   2. Glan prism

3. λ/4 plate        4. LiNbO3 crystal

5. Analyzer       6. Photo receiver

7. Aperture       8. LiNbO3 driver

9. Speaker      10. Laser driver


Experimental System for Electro-Optic Modulation.png  

Effect of dc voltage bias on output characteristic of electro-optic crystal

 Light intensity - DC voltage curve.jpg

Transmitted light intensity vs DC voltage


Linear and nonlinear modulation.jpg

Linear and nonlinear modulation

Blue: input; Red: output

LEOI-34 Experimental System for Electro-Optic Modulation

LEOI-34 Experimental System for Electro-Optic Modulation

Note: oscilloscope not included

Features

  • Including He-Ne laser with power supply

  • Precise optical alignment

  • Observe and measure electro-optic modulation waveform


  • Electro-optic modulation technique demo




Introduction

Electro-optic effect is a change in the refractive index of a crystal as induced by an electric field. If such change is linearly proportional to the applied electric field, linear electro-optic effect or Pockels effect is obtained; whereas the quadratic electro-optic effect is called as Kerr effect which is usually much weaker than Pockels effect in most crystals. This apparatus employs the linear electro-optic effect of a typical LiNbO3 crystal for students to

 

1. understand electro-optic effect and its applications

2. measure the half-wave voltage and electro-optic coefficient of crystal

3. observe a change in optical properties of crystals due to electro-optic effect

4. observe the interference of focused polarized light as caused by electro-optic effect

5. conduct experimental demonstration of laser communication

 

This experimental system can be used to conduct the following experiments:

 

1. Display electro-optic modulation waveform
2. Observe electro-optic modulation phenomenon
3. Measure half-wave voltage of electro-optic crystal
4. Calculate electro-optic coefficient
5. Demonstrate optical communication using electro-optic modulation technique


Specifications

Power Supply for Electro-Optic Modulation
  Output Sine-Wave Modulation Amplitude0 ~ 300 V (Continuously Adjustable)
  DC Offset Voltage Output0 ~ 600 V (Continuously Adjustable)
  Output Frequency1 kHz
Electro-Optic Crystal (LiNbO3)
  Dimension5×2.5×60 mm
  ElectrodesSilver Coating
  Flatness< λ/8 @633 nm
  Transparent Wavelength Range420 ~ 5200 nm
He-Ne Laser1.0 ~ 1.5 mW @ 632.8 nm
Rotary PolarizerMinimum Reading Scale: 1°
PhotoreceiverPIN Photocell


Part List

DescriptionQty
Optical Rail1
Electro-Optic Modulation Controller1
Photoreceiver1
He-Ne Laser (LLL-2)1
Laser Holder (SZ-42)1
LiNbOCrystal1
BNC Cable2
Four-Axis Adjustable Holder (SZ-24)2
Rotary Holder (SZ-51)3
Polarizer1
Glan Prism1
Quarter-Wave Plate1
Alignment Aperture1
Speaker1
Ground Glass Screen1



     LEOI-34 Experimental System for Electro-Optic Modulation.png

Schematic of transverse electro-optic modulation

S: Source laser         P: Polarizer

C: LiNbO3 crystal     A: Analyzer

V: Voltage                 D: Photo receiver

     Experimental System for Electro-Optic Modulation.png

Schematic of experimental configuration

1. He-Ne laser   2. Glan prism

3. λ/4 plate        4. LiNbO3 crystal

5. Analyzer       6. Photo receiver

7. Aperture       8. LiNbO3 driver

9. Speaker      10. Laser driver


Experimental System for Electro-Optic Modulation.png  

Effect of dc voltage bias on output characteristic of electro-optic crystal

 Light intensity - DC voltage curve.jpg

Transmitted light intensity vs DC voltage


Linear and nonlinear modulation.jpg

Linear and nonlinear modulation

Blue: input; Red: output

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