ucsd photonics 1092-channel two dimension array wavelength...

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


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)


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!


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)


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


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


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


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


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


UCSD PhotonicsOutput Spot Array

• 9 µm SM fiber scanned across output field to find maximum coupling positions

6.5 µm RMS positioning error


UCSD Photonics1092 WDM Channel Passbands

<10 dB loss over central 702 channels(39 x 28 array)

Tran

smis

sion

(dB

)

Wavelength (nm)


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


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


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

ucsd photonics 1092-channel two dimension array wavelength...

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