Schematic of transverse EO modulation
(Click figure to enlarge)
Schematic of experimental configuration
(Click figure to enlarge)
Effect of dc voltage bias on output characteristic of electro-optic crystal
(Click figure to enlarge)
Transmitted light intensity vs DC voltage
(Click figure to enlarge)
Linear and nonlinear modulation
Blue: input; Red: output
(Click figure to enlarge)
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
The instruction manual contains comprehensive materials including experimental configurations, principles and step-by-step instructions. Please click Experiment Theory and Contents to find more information about this apparatus.
Specifications
| Power Supply for Electro-Optic Modulation | |
| Output Sine-Wave Modulation Amplitude | 0 ~ 300 V (Continuously Adjustable) |
| DC Offset Voltage Output | 0 ~ 600 V (Continuously Adjustable) |
| Output Frequency | 1 kHz |
| Electro-Optic Crystal (LiNbO3) | |
| Dimension | 5×2.5×60 mm |
| Electrodes | Silver Coating |
| Flatness | < λ/8 @633 nm |
| Transparent Wavelength Range | 420 ~ 5200 nm |
| He-Ne Laser | 1.0 ~ 1.5 mW @ 632.8 nm |
| Rotary Polarizer | Minimum Reading Scale: 1° |
| Photoreceiver | PIN Photocell |
Part List
| Description | Qty |
| Optical Rail | 1 |
| Electro-Optic Modulation Controller | 1 |
| Photoreceiver | 1 |
| He-Ne Laser (LLL-2) | 1 |
| Laser Holder (SZ-42) | 1 |
| LiNbO3 Crystal | 1 |
| BNC Cable | 2 |
| Four-Axis Adjustable Holder (SZ-24) | 2 |
| Rotary Holder (SZ-51) | 3 |
| Polarizer | 1 |
| Glan Prism | 1 |
| Quarter-Wave Plate | 1 |
| Alignment Aperture | 1 |
| Speaker | 1 |
| Ground Glass Screen | 1 |
Schematic of transverse EO modulation
(Click figure to enlarge)
Schematic of experimental configuration
(Click figure to enlarge)
Effect of dc voltage bias on output characteristic of electro-optic crystal
(Click figure to enlarge)
Transmitted light intensity vs DC voltage
(Click figure to enlarge)
Linear and nonlinear modulation
Blue: input; Red: output
(Click figure to enlarge)
