1. Slow light: The route to faster communications
Professor Benjamin J. Eggleton
CUDOS Research Director
ARC Federation Fellow
School of Physics, University of Sydney
Slow light: The route to faster communications

2. Hunger for more bandwidth : Internet and Cellular Network2

3. Electromagnetic spectrum

4. 4

5. Underwater Optical Fibre Network
Each point on this diagram where two lines intersect represents a point where cables join.
This is much the same as merging major roads.
And as with merging traffic, it’s not good if things merge into each other.

6. Photonic chip – Photonic integrated circuit

7. Underwater Optical Fibre Network
Each point on this diagram where two lines intersect represents a point where cables join.
This is much the same as merging major roads.
And as with merging traffic, it’s not good if things merge into each other.

8. Merging traffic Each junction looks like this.
If two signals interact, they interfere and the message is lost.

9. What & Why? Slow light is … Fundamental interest Device applications:
pulse propagation at velocity << c, or
optical delay comparable to pulse duration
Fundamental interest
phase velocity (c/n): little control
group velocity (c/ng): enormous control
[e.g. L. V. Hau, Nature (1999): vg = 17 m/s]
Device applications:
enhance nonlinear effects
optical delay lines / optical buffers
TIME

10. Slow light: Atomic vs Photonic
Atomic resonance
“Cycling at the speed of light” in cold atoms
17 m/s (Hau et al., Nature 1999)
Narrowband (<MHz)
1. Slow light has been demonstrated using either atomic or photonic resonances.
2.1999, there was a demostration of light travelling at 17 m/s in a cloud of ultracold Na vapor. 2 yrs after that, the same group stopped light.
3. These are impressive results, HOWEVER, atomic resoanaces are narrow band, therefore not particularly useful for high bandwidth applications, for exmaple.
4.Instead in this work we try to slow light using a photonic resonance, which is comparatively broadband. Exmaples of such resonant structres include Bragg grating and photonic crystal

11. Slow light in photonic resonance
Bragg grating, photonic crystal
Broadband (>GHz)
Compatible with telecom!

12. Problem Problem: Our solution: dispersive broadening
length-limited  delay-limited
(fractional delay ~ 0.1 to 3)
Our solution:
Balance dispersion with nonlinearity
 Soliton!
here a gap soliton [Winful, Chen and Mills (1980’s)]
eliminate dispersion to all orders
 no length/delay limitation

14. eHealth
Astrophotonics
eTeaching
Defence applications

15. World leading research!
NSW, February 2008
Funding: , renewed
12 Chief Investigators, 50 researchers, 50 students, >20 international partners
Fundamental science, Strong collaboration, Major international programs, Strong IP, End-user engagement and commercialization path, Outreach, E&T etc 15