1. 28/05/2015CPqD 2015
Semiconductor Optical Amplifiers:
Linear Amplification;
Space Switches;
and Wavelength-Reuse Schemes
LAPCOM- Advanced Optical
Comm. & Microwave Lab.
FEEC –DECOM - Unicamp

2.  Authors
 Prof. Cristiano Gallep
 Prof. Aldário Bordonalli
 Dr. Napoleão Ribeiro (now with Fed. Gov.)
 Dr. Andrea Chiuchiarelli (now with CPqD)
 Dr. Marcelo Ribeiro
 Dr. Rafael Figueiredo
 Peterson Rocha
 Tiago Sutili
 Bruno Taglietti
 Prof. Evandro Conforti
11/27/2014LAOP 2014

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Summary: part 1
SOA Amplifiers: Linearization
Scheme
Introduction;
Results (simulated);
 Conclusion.

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What is a SOA
Diode Laser: amplifier gain medium
+ facet mirrors to reflect light
(backward and forward)
 SOA: laser without the facet
mirrors
So, the light is amplified traveling
just one time in the gain medium

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Electrical
Current
Light IN
Light OUT +
SOA Noise
(ASE)
Anti-
reflection
<< Gain Region
with optical
waveguide
SOA illustration
Anti-
reflection

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SOA Phase Noise

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Nearly-Linear SOA scheme
 P. Rocha. C.M.Gallep, E. Conforti, Patent Pending, BR1020140306363, 12/12/2014, Padtec-
Unicamp.
Gain Region
(optical waveguide
with 2 SOAs )
Second SOA
acts as a
Saturable
Absorber

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After First
SOA
After Second
SOA
(VPI simul.)
 P. Rocha. C.M.Gallep, E. Conforti, Patent Pending, BR1020140306363, 12/12/2014,
Padtec-Unicamp.
Before First
SOA
(10 Gbaud)

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Summary: part 2
SOA Space Switches
Introduction;
Experimental Setup;
 Results;
 Conclusion.

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 Optical fiber presents itself as a fundamental technology for scientific and
technological advancement.
 The growth of transport capacity of information based on the internet
protocol (IP) has fueled the development of high-speed transmission
systems.
However, there is a bottleneck due to processes necessary for switching and
routing of IP packets.
 Therefore, Photonic Networks present themselves as future solution.
Nevertheless, a necessary transition technology is necessary
 Optical transition technologies under development:
• Optical Packet Switching (OPS);
• Optical Burst Switching (OBS);
• All-Optical Label Swapping (AOLS).
Introduction

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 In these technologies, optical packet switching and optical signal
regeneration are features of great importance.
 The SOA is a promising device for realizing these features.
 SOA advantages :
• Small size (can be integrated)
• High gain (> 30 dB)
• Low dependence of signal polarization (1 dB)
• Non-linear properties on saturation
• SOA disadvantages
• non linearity
• phase noise
• high energy consumption per bit
Introduction

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Optical Switch Switching Time
MEMS 0,01 a 1 ms
Thermo-optical < 4 ms
Acousto-optical Hundreds of ns
All Optical Switch < 100 ps
Electro-optical Switch Switching Time
LiNbO3 5 ns
Liquid Cristal Hundreds of s
Holographic < 10 ns
Bragg Grating 10 a 50 ns
SOA 115 ps
Introduction

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RESUME
So, Optical Networks (ON) and Data Centers
(DC) requires low latency with fast bandwidth
delivery and restoration.
Optical Space Switches are essential
part of high speed ON & DC;
We will show results for electro-
optical switches based on
Semiconductor Optical Amplifiers (SOA)

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How to operate the SOA electro-optical
switches: by controlling the electronic current
that drives the optical devices.
Example of application: a Data Center
containing optical space switches where
some of the SOAs are turned off/on
by conveniently controlling
the SOAs bias currents.

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 W. Miao, J. Luo, S. diLucente, H. Dorren, and N. Calabretta. Opt. Exp. Vol. 22
N.3, 2014. Cobra Institute, Netherlands
SOA Switch
Electrical Control
Practical Example of 2014

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(c) SOA
optical response
for
electrical input of (a).
Switch Operation
(a) Electrical step,
IDC = 80 mA;
(b) optical gain
curve
of the SOA;
rise time

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PISIC - Pre - emphasis technique
 C.M. Gallep and E. Conforti. IEEE PTL, 2002 .

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The ideal and real
current PISIC pulse
obtained (IEEE PTL 2009)
PISIC Result

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(a)Experimental setup for electro-optical switching
analysis;
(b) example of PISIC and MISIC formats (JLT, 2015).
New approach : MISIC

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(a) Misic1 electrical pulse (IDC = 80 mA) (b)
SOA optical response to (a). ( JLT, 2015)
New approach : MISIC
115 ps
Reduced variations

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Limitation: the energy consumption
needs improvement since several SOAs
must be located in a practical switch
It is necessary to integrate the
microwave circuit with the SOAs and
optical waveguides (hybrid solutions ?).
weakness

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Optical Table

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MISIC with SOA Chip setup

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MISIC with SOA Chip setup
( JLT, 2015)

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MISIC with SOA Chip setup

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SOA Chip

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SOA Chip setup Modeling

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Experimental (solid line) and theoretical (dotted line)
SOA microwave mount input electrical impedance
modulus and phase ( JLT, 2015).
SOA Chip Impedance

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Experimental (solid line) and theoretical (dotted line)
SOA optical output normalized power versus the
microwave injected current frequency (JLT, 2015)
(SOA bias of 60 mA and -10 dBm optical input power).
SOA Chip Electro-optical resp.

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Equivalent circuit for the SOA mount of Fig 8 (at 60 mA
SOA bias). (a) the upper part represents the microwave
injection current mount, has fixed values and should be
directly connected to the (b) lower part representing the
SOA ( JLT, 2015)

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Experimental and simulated SOA optical
response ( JLT, 2015)
MISIC: Theory and Experiment

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Wavelength-Reuse Schemes
Introduction;
 Main proposal;
Experimental Setup;
 Results;
 Conclusion.
Summary: part 3

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Introduction
>> WDM-PON Networks in FTTH (Fiber-To-The-Home).
>> If the same carrier is used for the return channel,
efficiency will be higher and prices might decrease.
Wavelength Reuse

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Main approach

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Experimental setup (< 12.5Gb/s)
>> Erasing quality decrease
slightly with bit rate. *
* N. Ribeiro, C. M. Gallep and E. Conforti,
Optics Express v. 18, p. 27298-27305, 2010.

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Resultados experimentais
* N. Ribeiro, C. M. Gallep and E. Conforti, OFC 2011.
>> Erasing quality (BER) for 7
Gbit/s downstream and 12.5
Gbit/s upstream.

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Experimental setup ( up to 56 Gb/s)

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Exp. with 25 km of Fiber
*
* N. Ribeiro. C. M. Gallep and E. Conforti, JLT 2013

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Setup of the optical access network with Fabry-
Perot based wavelength converter at RN for
optical multicast transmission.
* Andrea Chiuchiarelli, C. M. Gallep and E. Conforti, Patent Pending,
BR102014018890, 28/07/2014, Padtec-Unicamp.
Reflective
SOA

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Upstream bit error rate curves for the wavelength-
converted optical channel at another wavelength.
Inset: eye diagram of the remodulated signal.
* Andrea Chiuchiarelli, C. M. Gallep and E. Conforti, Patent Pending,
BR102014018890, 28/07/2014, Padtec-Unicamp.

44. Conclusions
28/05/2015CPqD 2015
>> SOAs have the potential to be used in
Optical Switching and in
non- linear applications such us wavelength
reuse.
>> However, improvements on price and
development of Photonic Integrated Circuits with
SOAs are necessary to improve speed and
performance.

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Sponsors
CPqD 2015