FW-LN-007

LiNbO₃(LN) crystal, also know as “Optical Silicon” is a transparent crystal having several properties such as electro-optic, acousto-optic, photo-elastic, nonlinear and photo-refractive. This makes it an important functional material in optoelectronic industry. Lithium Niobate crystals are widely used in laser communication, optical information processing, optical integrated circuit substrates, image storage, laser frequency doubling and self frequency doubling as well as optical parametric oscillation.

Characteristics of optical grade LiNbO₃ crystal:

1. crystal structure: trigonal system
2. space groups: C36 (R3C)
3. melting point: 1260 ℃
4. Moh’s hardness：～4.8
5. density：4.46g/cm³
6. coefficient of thermal expansion: 16.7
7. Optical transparency range：370～5000nm
8. refractive index：（633nm）n0=2.286 ne=2.200
9. refractive index gradient：（633nm）≤5×10-5
10. light transmission：（633nm）≥68%
11. orientation：X±0.1°
12. size：Φ2-4〞×40～80mm

Applications:

Surface acoustic wave filter, isolator, narrow-band filter, sensor, the photon tunable filter, acousto-optic device, Optical gyroscope, optical waveguide, photoswitch, light modulation direction coupler, Optical modulator, Interferometer gyrator, High-speed long-distance communication devices and double-frequency device.

Innovation point: Through the growth equipment modification, we create simulation of crystal growth system and can design crystal shape. The computer chip control the changing of crystal shape according to crystal growth status, through the processing of precision sensor signals. We self-design a set of graded composite temperature structure. With the help of it, the temperature gradient in crystals, melt and the solid liquid interface reach the good state for optical crystal growth.