1. Photon2 Internship PENN STATE UNIVERSITY Materials Research Lab June 2005 Paul Longwell

2. Dr. Venkatraman Gopalan Cooperating Faculty

3. Topic: Fiber Optic Communication Focus – Signal Modulation (Encoding Information to be Sent)

4. Fiber Optic Communication Begins With Laser Light The light is produced by a tiny diode. www.gcse.com

5. Fiber Optic Communication Information (Voice, Websites, Etc) is Encoded into Pulses. First, a laser beam is split into two identical beams. How?

6. Fiber Optic Communication Information is Encoded into Pulses Each beam travels an identical path and then they are recombined, but…. www.photonics.com

7. Fiber Optic Communication Information is Encoded into Pulses …one beam must pass through an ELECTRO-OPTIC crystal.

8. Fiber Optic Communication Information is Encoded into Pulses When an electronic signal is delivered to the crystal, the light wave shifts. Many layers in a thin device! 2002 den Besten, et al

9. Fiber Optic Communication Information is Encoded into Pulses When the light waves recombine, the result is ON (pulse) or OFF (no pulse) The ON and OFF signals carry the code of information! Identical Waves One Shifted Wave ON OFF

10. Fiber Optic Communication To study the splitting and recombining of a laser beam, I tried it! Mach-Zehnder Inteferometer

11. Fiber Optic Communication Recombining the Beams Perfectly is Challenging! Good Bad

12. Fiber Optic Communication “Perfectly” Aligned! Good Fringes Seen On the White Paper

13. Fiber Optic Communication How do the laser pulses carry the information from one place to another? www.corning.com

14. Fiber Optic Communication Fiber optic cables contain several layers:

15. Fiber Optic Communication Total Internal Reflection allows the light to remain in the fiber optic cable as it travels.

16. Fiber Optic Communication After the light has traveled through the cable, the initial encoding process is essentially reversed and the information is delivered. www.corning.com

17. Other Internship Images A diffraction grating used in laser experiments

18. Other Internship Images

20. Thank You Dr. Venkatraman Gopalan Sava Denev Lili Tian Aravind Vasudevarao