1. Photonics Systems Group
Photonics Systems Group Projects
R.J. Manning
Fatima Gunning
Cleitus Antony
Giuseppe Talli

2. Photonics Systems Group
Photonics Systems Group (PSG)
State-of-the-art photonics laboratory
Internationally recognised research
Uses an enormous range of disciplines, from basic Physics to applied Electrical Engineering

3. Project 1: Chirp Characterisation of Optical Modulators
Projects
Project 1: Chirp Characterisation of Optical Modulators
Dr Giuseppe Talli and Dr Cleitus Antony (12 weeks)
Project 2: Raman Amplification for Fibre-to-the-home networks
Dr Giuseppe Talli and Dr Cleitus Antony (6 weeks)
Project 3: Characterisation of 2mm lasers
Dr Fatima Gunning and Dr Hongyu Zhang (12 weeks)
Project 4: Optical frequency shifter based on a semiconductor
optical amplifier
Dr Bob Manning (6 or 12 weeks)

4. Today’s Telecommunication Networks
Optical access network (i.e. “fibre broadband”) is currently being deployed across the world in different flavours
Fibre
Access Network
(Last/First mile)
Copper

5. Project 1:Chirp in Optical Modulators
Chirp in optical modulators changes the frequency (hence wavelength) of the optical signal
Due to chromatic dispersion in fibre the different frequencies travel at different speeds
LASER
Optical Modulator
Photo-detector
Optical Fibre
Correct colours for anomalous dispersion in fibre (eg 1550nm)
Red is slower than Blue t t

6. Chirp in Optical Modulators
Chirp in optical modulators changes the frequency (hence wavelength) of the optical signal
Due to chromatic dispersion in fibre the different frequencies travel at different speeds
Pulse broadening or compression
Optical Modulator
LASER
Photo-detector
Optical Fibre t t

7. Optical Modulators Chirp Characterisation
Project Description:
Characterise experimentally the chirp of different modulators:
Mach-Zehnder Modulator
Electro-absorption Modulator
Integrated Semiconductor Optical Amplifier Electro-absorption Modulator
Analyse the performance of the modulators in a fibre communication systems
Numerical modelling using commercial software tools
Experimental characterisation of fibre transmission
No. of Students:
1 or 2

8. Optically Amplified Links
Optical Amplifier
~80 km
N × 80 km Tx Rx
The signal is amplified in the optical domain
No high-speed electronics is required
Multi channel
Bit rate independent
In the 80s the fibre amplifier revolutionased the networks, getting rid of the repeaters and allowing for the first time to have transparent link from end to end, with no high speed electronics.
This meant that is was very easy to add new channels and also that the speed of the channels could be upgraded without changing the link.

9. Raman Optically Amplified Links
Raman Pump Laser
~80 km
N × 80 km Tx Rx
The same optical fibre used for transmission can be used to provide optical gain
Raman Amplification
Very attractive as it can reduce the equipment deployed in the field

10. Raman Amplification for Fibre to the Home Applications
Raman Pump Laser
Explore the use of Raman amplification for fibre to the home (FTTH) communication links
Different wavelength from long reach systems (1.3mm)
Newly developed pump lasers
60 km Tx Rx
Project Description:
Experimental characterisation of the Raman gain
Analyse the overall performances of the FTTH communication link
Numerical modelling using commercial software tools
No. of Students: 1

11. Fatima Gunning, Hongyu Zhang
Project 3: Characterisation and applications of 2µm lasers 4th year project (12 weeks)
Fatima Gunning, Hongyu Zhang
Photonic Systems Group
Tyndall National Institute

12. Can 2µm be the 4th transmission window?
lasers
filters
fibre
detectors

13. Full optical high-speed systems tesbed
4th year project:
Characterisation and applications of 2µm lasers
(slotted Fabry-Perot lasers)
MODEGAP meeting, Aston, 3rd/4th October 2013

14. 2µm systems – 2013 Selecting Eblana lasers
s available
s requested
old lasers
MODEGAP meeting, Aston, 3rd/4th October 2013

15. Typical laser characterisation
MODEGAP meeting, Aston, 3rd/4th October 2013

16. Objectives
Understanding operational principle of slotted Fabry-Perot lasers
Analysis of threshold current
Tuneability against temperature
High speed data characterisation

17. Project 4: Optical frequency shifter
Semiconductor Optical Amplifiers (SOA)

18. Project description
SOAs are very NONLINEAR
When subject to high intensity light, their refractive index changes
This can be used to impart a time-dependent phase change (or frequency shift) on a continuous wave (cw) light beam
This can the be the basis of a frequency shifter
Project consists of :
Modelling of phase and frequency shifts using Fourier theory
Experimental measurements to directly observe achievable phase shifts

19. Please Visit!
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