Realistic
R
li i modeling
d li off
high-speed electrical and
optical components
Professional solutions for
optical component and system design
March 2011
VPIphotonics is a division of VPIsystems.
Copyright VPIsystems. All rights reserved.
Integrated
g
I-Q
Q Transmitter
Electrical eye diagram after driver amplifier
80Gb/s
Copyright VPISystems. All rights reserved
model of transmitter electronics and
driving
model of transmitter frequency
response
2
Integrated
g
I-Q
Q Transmitter
IImportant
t t tto model
d l
electronics and driving circuitry
transmitter frequency response
Small Signal Response (S21) of the four MZM electrodes*
Electrical eye after driver amplifier
80Gb/s
Different electrical response at electrodes of
transmitter imbalances I&Q branches
* Measurements provided by FhG-HHI
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3
Integrated
g
I-Q
Q Transmitter
Effect of RF response*
• 80 Gb/s
• DQPSK
• 25 dB OSNR
4dB
<3dB
Ideal RF
responses
Measured RF
responses
Transmitter imperfections may limit
significantly
i ifi
tl system
t
performance
f
*C.
5 ps/nm
25 ps/nm
Arellano et al, paper FU2, OECC 2009.
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4
Integrated
g
I-Q
Q Transmitter
Different electrical responses at tx electrodes imbalance I&Q branches
Small Signal Response (S21) of the four MZM electrodes*
40 Gb/s
* Measurements
provided by FhG-HHI
Copyright VPISystems. All rights reserved
Simulated
Measured
5
Integrated
g
I-Q
Q Transmitter
40 Gb/s DPSK (el)
80Gb/s DQPSK (el)
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6
8PSK at 20 GBaud/s
Simulated
Measured
Measurements provided by HHI (EURO-FOS)
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(OSNR = 20 dB)
7
8PSK Transmitter – Realistic Design
Frequency response of the pulse shaping
filter
• No frequency response data available
• Estimated
d ffrom measured
d eye diagram
d
• Modeled by low-pass electrical filter:
Elliptic order 4,
Elliptic,
4 cutoff freq
freq. 22.5
22 5 GHz
Effect of the time delay
• Time delay I-Q
imbalance unknown
• Swept
S ept of time delay
dela
M
Measured
d
no delay imbalance
Si l t d
Simulated
delay imbalance = 17 ps
Measurements provided by HHI (EURO-FOS)
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8
8PSK at 20 GBaud/s
Received signal
Measured
Tx model includes MZM & electrical filters
responses, not optimal bias, …
Simulated
Rx model includes optical front end, modeling,
digital filter of sampling oscilloscope, DSP
Measurements provided by HHI (EURO-FOS)
Copyright VPISystems. All rights reserved
9
8PSK at 20 GBaud/s
Back-to-back performance
p
Realistic simulation of complex
transmission system requires
accurate characterization of
electrical & opto-electrical
components
1.00E-01
1.00E-02
SER
1.00E-03
Identified constraints: driver
amplifier (noise, jitter & frequency
response), MZM (bias, frequency
response) synchronization between
response),
electrical tributaries
1.00E-04
1.00E-05
ideal results
experimental results
1.00E-06
realistic
results
5.00 simulation
10.00
15.00
20.00
OSNR [dB]
Measurements provided by HHI (EURO-FOS)
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10
Integrated
g
Balanced
Photo-Receiver
Jones Matrix
PDL model
Optical
input
ITHCP
Control
currents
Responsivity
(λ,temp.)
Realistic model for balanced photo-rx
- OE transfer function: BW,, ripple,
pp ,
transimp gain
- PDL, responsivity (, temp.)
V+
V-
Differential
electrical
output
ITHCN
Detailed model for the
transimpedance amplifier
Transimpedance
Gain
I+
I-
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Differential
Limiting
Transimpedance
Amplifier
Frequency
Response
Limit
V+
V11
Detailed model for the
transimpedance amplifier
Non-linear limiting function*
Electrical RF Response from measurements*
Transimpedance gain
Static Transfer Function
Delay
*Measurements provided by u2t
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12
43Gb/s DPSK System
y
Simulated
Measured
*Measurements provided by u2t
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13
Additional Validation Results
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14
Validation of Modeling
Alcatel (Italy)
Duobinary Modulation
Simulation vs Experiment
1.0E-02
B2B
20 km
60 k
km
100 km
B
BER
1.0E-04
1.0E-06
Eyes after 20km
1.0E-08
1.0E-10
1.0E-12
-32
-30
-28
-26
-24
ROP (dBm)
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15
BER estimation for NRZ-DPSK
Experimental validations*
NRZDPSK
• 10 Gbit/s NRZ-DPSK
• WLS – white light source
• PDFs measured at balanced output
with
1. PIN2 disconnected
2 PIN1 disconnected
2.
di
t d
3. PIN1 & Pin2 connected
after PIN2
after PIN1
after Sub
x experiment
– simulation
* performed by R. Freund and team at the FhG-HHI
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16
BER estimation for NRZ-DPSK
Experimental validations*
NRZDPSK
p
perfect
agreement
• 10 Gbit/s NRZ-DPSK
• WLS – white light source
• PDFs measured at balanced output
with
1. PIN2 disconnected
2 PIN1 disconnected
2.
di
t d
3. PIN1 & Pin2 connected
after PIN2
after PIN1
after Sub
x experiment
– simulation
* performed by R. Freund and team at the FhG-HHI
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17
More validation results
OTDM with saturable absorber [2]
Yb Fiber amplifier [1]
EAM [3]
[1] F. He al., / OPTICS EXPRESS Vol. 14, No. 26 (2006)
[2] A.M. Clark et al, IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 19, NO. 5, (2007)
[3] I. Koltchanov, et al, OFC, paper OME42. (2005)
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18
Thank You!
Product enquiries:
Sales@VPIphotonics.com
Technical support:
Support@VPIphotonics.com
Information about Products & Applications:
www.VPIphotonics.com
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