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11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 1
UCSD Photonics
Photo: Kevin Walsh, OLR
University of California San DiegoJacobs School of Engineering
University of California San DiegoJacobs School of Engineering
Data Transmission Through a1092-Channel Two DimensionArray Wavelength Multiplexer
Data Transmission Through a1092-Channel Two DimensionArray Wavelength Multiplexer
Trevor Chan, Rui Jiang, Nikola Alic, Stojan Radic, Joseph FordTrevor Chan, Rui Jiang, Nikola Alic, Stojan Radic, Joseph Ford
Photonics Systems Integration Lab
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 2
UCSD PhotonicsWhat Limits Total Fiber Bandwidth Capacity?Theoretical limit at least 100 Tb/s - How close are we now?1980 – 2000 saw exponential growth in single-fiber
bandwidth to 3 Tb/s
Why the slowdown?• Telecom bust forced emphasis on range/cost• Technology limits:
Fiber and amplifier spectral width, spectral efficiency, link engineering
Achieving record bandwidth requires multiple WDM technology advances1. Many channels (~1000)2. Greater spectral bandwidth /
high bandwidth channels (40 GHz)Not feasible with a single-stage
wavelength mux/demux
Theoretical Transmission? 4 bits/s/Hz * 1000 nm
Mitra and Stark, Naturev.411, p. 1027. June 2001.
0
5
10
15
2000 2001 2002 2003 2004Year
Cap
acity
(Tb/
s)
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 3
UCSD PhotonicsHierarchical Multiplexing Alternatives
BandwiseBroad, tight-spaced bands then DWDM
Interleaved Interleaved WDM then CWDM
CWDMInterleavedBand
DWDM
NTT demonstrated Bandwise Hierarchical DeMUX using many cascaded AWGs1010 DeMUX (1x10 then 1x160 AWGs): K. Takada et al, Phot. Tech Lett., 577, June 20014200 DeMUX, 16.8 THz total bandwidth: K. Takada et al., Electronics Lett, 38 (12), 572-3,
2002. Used 21 AWGs!
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 4
UCSD PhotonicsSurface-Normal Optical WDM Components
WDM Components Demo’d- Spectral equalizer
LC or MEMS VOA- Add/drop
MEMS tilt mirrors - Dispersion compensator
MEMS mirror- Channel monitor
OE power monitors- WDM Transceivers
VCSELS, MQW mods, OE Receivers
λ-Multiplexing:Waveguide and/or Grating
Surface-normalDevice
Fiber I/O
Capella Photonics Wavepath 9600
MetconnexWSS 5400 1x9
JDSU Wavelength Selective Switch 1x9
Current Commercial Products (Linear Arrays)
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 5
UCSD Photonics2-Dimensional Hybrid Wavelength Demultiplexing
Combine an AWG and a free-space optical grating demultiplexer– Dragone & Ford, US Patent #6,263,127, 1999.
Fourier-Transform Lens focal length = f
Blazed Gratingline spacing = d
AWG Demultiplexer
Wavelength
Tran
smis
sion
Intermediate transmission spectrum
Wavelength
Tran
smis
sion
Net, single channel transmission spectrum
λ4>λ3>λ2>λ1
127 µm
−
−1
12
2
22
mm
dfλ
−
−1
12
1
11
mm
dfλ
Row:
−
−1
12
3
33
mm
dfλ
1
2
3
4
Spot Positions
First published experimental 2-D deMUXS. Xiao and A. M. Weiner, Optics Express 12 (13), p.2895-2902, 2004Multi-order VIPA (Virtual Image Phased Array) + free space grating
41 Channels (~4x10), 17 dB lossTotal aggregate bandwidth = 71.75 GHz
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 6
UCSD PhotonicsOFC 2005: 72 Channel Proof of Principle
Passband narrowing due to FSO MUX72 channels with 50 GHz pitch
1530.0 nm1530.4 nm
1532.8 nm
1537.8 nm
1597.9 nm
Wavelengths of peak ASE
power
Noise from PBS surface reflections
(multi-spectral)
MM+1
M+2M+3
M+4
M-4M-3
M-2M-1
-55-50-45-40-35-30-25-20-15-10
-50
1562.65 1562.75 1562.85 1562.95 1563.05 1563.15
Wavelength (nm)
Inse
rtio
n Lo
ss (d
B)
Stage 1 AWG passband
Final passband
Fiber ribbon
V-groove array
Polarization beamsplitter
¼ wave plate
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 7
UCSD PhotonicsHybrid Wavelength Demultiplexer v2.0
• First stage AWG1x 8 AWG→ 1x 40 AWG (one channel disabled)
• Second stage FSO50 mm lens + 300 lp/mm grating→ Reduced dispersion 75 lp/mm grating
• Operating spectrum100nm EDFA ASE source→ 600 nm parametric source
• Output collectionManual alignment→ Automated hexapod stage (0.1µm)
Grating
Lens
40 AWG
Outputs
1x40 input array
Outputfiber
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 8
UCSD PhotonicsSpectral EvolutionInput: Parametric Source
1100nm to >1750nm (OSA range)
Stage 1 (AWG) Output
39 channels at ~20nm AWG FSR
Stage 2 (FS Grating)Output
Isolated singlechannel
8 dB normalized IL (central λ)>25 dB suppression30GHz passband 3dB rolloff
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
UCSD PhotonicsImage of Output Plane
• 2D array relayed onto an InGaAs detector array– Intensity variation reflects source nonuniformity– 25 x 25 µm pixels can not resolve output array– SMF Fiber is a better measurement of spot distribution
4.83 mm
Imaging SetupGold mirror
IR Camera
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 10
UCSD PhotonicsOutput Spot Array
• 9 µm SM fiber scanned across output field to find maximum coupling positions
6.5 µm RMS positioning error
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 11
UCSD Photonics1092 WDM Channel Passbands
<10 dB loss over central 702 channels(39 x 28 array)
Tran
smis
sion
(dB
)
Wavelength (nm)
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 12
UCSD PhotonicsChannel profile
• 25 dB SNR• 0.22 dB PDL in the c-band• 0.24 nm 3 dB rolloff
(no bandwidth narrowing)
AWG outputTotal output
25 dB0.24 nm
AWG Loss: 4 dBFS Grating Loss: 3.4 dBTotal IL: 7.4 dB @ 1533.7 nm
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 13
UCSD PhotonicsData Transmission
• Modulated PRBS tuned to channel at 1543.9 nm• 0.1 dB power penalty at 10 Gb/s
Single sideband modulation: potentially up to 40 Gb/s/channel
-12
-10
-8
-6
-4
-2
0
-22 -20 -18 -16
Input Power (dBm)
log(
BER
)
10 Gb/s baseline
10 Gb/s
2.5 Gb/s baseline
2.5 Gb/s
11/1/2007 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 14
UCSD PhotonicsConclusion
• Successful division of 1092 wavelength channels –50 GHz spacing–600 nm bandwidth–Reliable data throughput – 0.1 dB power penalty @ 10 Gb/s
• Assume 80% bandwidth utilization =44 Tb/s
data transmission
• Much spectral bandwidth remains available• Improvements:
– No dead space between AWG diffraction orders– Extended bandwidth
Potential for 5000 channelsT.K. Chan, J. Karp, R. Jiang, N. Alic, S. Radic, C.F. Marki, J. E. Ford, J. Light Tech (Submitted).
• Acknowledgements:– Chris Marki– Jason Karp