Final Year Projects in Integrated Photonics

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1 Final Year Projects in Integrated Photonics Integrated Photonics Group Final Year Projects in Integrated Photonics September 25, 2017 Slide 1

2 The Internet not slowing yet Final Year Projects in Integrated Photonics September 25, 2017 Slide 2

3 Optical vs. Copper vs. Wireless > 99% of the internet is over optical fibre 100s of km Copper Wireless Final Year Projects in Integrated Photonics September 25, 2017 Slide 3

4 How is light used? Light is turned on and off, for digital ones and zeros Then, multiple colours can also be used Final Year Projects in Integrated Photonics September 25, 2017 Slide 4

5 Can we just keep adding more wavelengths at higher data rates? Final Year Projects in Integrated Photonics September 25, 2017 Slide 5

6 Increase the number of colours? Available space in optical fibre The channels eventually interfere! Final Year Projects in Integrated Photonics September 25, 2017 Slide 6

7 Increase the data rate? E t 2 E h t Available space in optical fibre The channels eventually interfere! Final Year Projects in Integrated Photonics September 25, 2017 Slide 7

8 Bit Rate Distance Product (Tbit/s.km) The end is near WDM TDM OFDM/CoWDM Coherent Detection Fundamental Limit (for ones and zeros) New technology required 1 Laboratory Results

9 What improvements are possible? Polarisation Use 2 orthogonal polarisations: Increases bandwidth by 2x Done (boring) Final Year Projects in Integrated Photonics September 25, 2017 Slide 9

10 What improvements are possible? Space Light path Use N orthogonal modes of optical fibre: Increases bandwidth by N Very current, very expensive Final Year Projects in Integrated Photonics September 25, 2017 Slide 10

11 What improvements are possible? Amplitude & Phase The Amplitude No Signal The Phase Coláiste na hollscoile Corcaigh, Éire University College Cork, Ireland ROINN NA FISICE Department of Physics 11

12 What improvements are possible? Amplitude & Phase 2bits/pulse 4 bits/pulse 5 bits/pulse Already implemented and expensive: But room to invent more cost effective solutions using interesting Physics

13 What improvements are possible? Coherence Available Frequency Separate Superchannels Channels

14 What improvements are possible? Coherence Requires coherent optical comb Available Frequency No current commercial Superchannels solutions: Focus of research group

15 What we want on a single chip Modulator Laser Comb Modulator Modulator

16 Required components Low linewidth laser Optical Demux None suitable commercially for narrowly spaced coherent combs Optical Mux Laser Comb Comb generation Modulator Modulator Modulator Integrated Modulators

Injection locks a slave laser to each line in the optical comb.

17 Design of Integrated Optical Demultiplexers The current design of the integrated optical demultiplexers works by: 1. Passively splits the injected comb using a Multimode Interferometer (MMI) 2. Injection locks a slave laser to each line in the optical comb. Side Mode Suppression Ratio SMSR Passive power splitter Injection locked slave laser SEM image of a 1x4 MMI integrated with slotted Fabry-Pérot slave lasers

Mach-Zehnder modulator EDFA: Erbium doped fibre amplifier PIC:

18 Power (dbm) Laser injection locking Optical Comb Generated TLS: Tuneable laser source PC: Polarization controller MZM: Mach-Zehnder modulator EDFA: Erbium doped fibre amplifier PIC: Photonic integrated circuit OSA: Optical spectrum analyser Wavelength(nm)

19 Power (dbm) Laser injection locking Wavelength(nm)

20 Power (dbm) Laser injection locking Slave laser s lasing mode Injected Comb SMSR Slave laser s side mode Wavelength(nm)

21 Theoretical model The complex expression d dt E s for the slave laser s filed was split into real and imaginary parts: d dt E s t = 1 2 G N N t N th E s t + d dt φ s t = 1 2 H G N N t N th j E j cos δω j φ s t + E s t sin δω j φ s t The carriers were modelled by: d dt N t = R N t p G τ N N t N th E s t 2 1 E s τ s t 2 p Equations (1), (2) and (3) were solved numerically using a 4th Order Runge-Kutta method. A fast Fourier transform was then used to obtain the spectral information. j E j (1) (2) (3)

22 Types of Projects Simulation: Solving analytical equations Based on existing code Requiring code development Experimental Mix of Experiment and Theory Final Year Projects in Integrated Photonics September 25, 2017 Slide 22

theoretical simulation and analysis addition available.

23 Laser Testing Develop LabView based characterisation of diode lasers including: Electrical Optical Gain Possible theoretical simulation and analysis addition available. Final Year Projects in Integrated Photonics September 25, 2017 Slide 23

24 A ring laser CW Ring CCW CW Ring CCW Final Year Projects in Integrated Photonics September 25, 2017 Slide 24

25 Laser linewidth ΔEΔt ħ 2 ΔνΔt 1 4π How long does an electromagnetic wave retain mathematical perfection? Δt c E = E 0 ei kx ωt : Coherence time Δl c = cδt c : Coherence length Δν c : Linewidth Final Year Projects in Integrated Photonics September 25, 2017 Slide 25

26 Power Level / dbm Laser Linewidth Characterisation Student will learn to characterize noise of and measure laser linewidth: Using loss-compensated recirculating delayed self-heterodyne interferometer (LC-RDSHI) Sources of Noise in Electrical Test Equipment Optical Test Equipment E E E Frequency / Hz Final Year Projects in Integrated Photonics September 25, 2017 Slide 26

27 Starting Mode in Waveguide Final Year Projects in Integrated Photonics September 26, 2016 Slide 27

28 Starting Mode enters larger region Final Year Projects in Integrated Photonics September 26, 2016 Slide 28

29 Light Propagates through device Final Year Projects in Integrated Photonics September 26, 2016 Slide 29

30 Starting Mode exits in two pieces Final Year Projects in Integrated Photonics September 26, 2016 Slide 30

31 Top View Final Year Projects in Integrated Photonics September 26, 2016 Slide 31

32 Laser-laser interactions Project #4 Optical Simulations VOA=Variable Optical Attenuator (more than one topic possible)

33 PICdraw Custom Design tool Final Year Projects in Integrated Photonics September 25, 2017 Slide 33

34 Mathematical based design Custom software used to design the complex devices Final Year Projects in Integrated Photonics September 25, 2017 Slide 34

35 Simulation and fabrication of complex photonic devices Project #5 Software for Photonic Device Design Final Year Projects in Integrated Photonics September 25, 2017 Slide 35

36 Get your hands dirty? Project #6 Making Stuff (come and talk to me ) Final Year Projects in Integrated Photonics September 25, 2017 Slide 36

37 e.g. Czerny-Turner spectrometer Final Year Projects in Integrated Photonics September 25, 2017 Slide 37

38 6 possible project areas: Experiment Theory Programming 1 Laser Measurements Yes possible LabView 2 Laser Theory No Yes likely 3 Laser Linewidth Yes Yes LabView 4 Simulations No Yes likely 5 Optical design tools No Yes C++ 6 Making things Yes?? Please contact me if you have any questions about any of the project options. Final Year Projects in Integrated Photonics September 25, 2017 Slide 38

S.R.M. University Faculty of Engineering and Technology School of Electronics and Communication Engineering

S.R.M. University Faculty of Engineering and Technology School of Electronics and Communication Engineering Question Bank Subject Code : EC459 Subject Name : Optical Networks Class : IV Year B.Tech (ECE)