real case studies of plc using sio2 on si

8/2/2019 Real Case Studies of PLC Using SiO2 on Si

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Real Case Studies of PLC using

SiO2 on Si

EE383P

Ray Chen


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Complex Circuits Are Built Out of Simple Elements

Overview Applications of OpticalAdd/Drop Modules

Drivers for Integration

Building Blocks for Integrated OADMs

Arrayed Waveguide Grating Multi-Demultiplexers

Switches and Switch Arrays

Variable OpticalAttenuators (Using heat to changeproperties)

Integrated OADM Modules and Sub-systems Potential Cost/Performance Benefits

Challenges Conclusions


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Emerging Optical Networks

Metropolitan

Ring

OADM

OADM

OADM

OXC

CO

CO

CO

WDM

FTTC

Module

OADM

FTTH

Module

Distribution

Node

Long Haul

Metro

Access

As DWDM Penetrates the Metro/Access Networks, the Numbers of Optical Add/Drop

Multiplexers (OADM) and Optical Cross-Connects (OXC) will Increase Substantially


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Cost Reduction Increases Market

Decreased Cost Required for Wide Deployment of OADM

Decreasing Cost Per Function Opens New Markets

Similar Cost/Volume Avalanche as in Electronics

TotalMark

et

Decreasing Cost PerFunction

Long Haul

Metro

Access

Premise

FTT?


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OADMs Will Fill Many Roles

Static Drop One or More Fixed Wavelengths

Require Physical Intervention to Provision (Truck Roll)

Most Common Current Deployment Partially Reconfigurable

Can Dynamically Drop Up To 25% of Channels

Must Predetermine Which Channels Can Be Dropped

Many Systems Announced

Fully Reconfigurable Dynamically DropAny orAll Channels

Most Flexible

Expected to be an Enabling Technology for Metro


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Components For Reconfigurable

OADMs Many Components Required For Full Reconfiguration

DWDM DeMultiplexers

Switches

VariableAttenuators The Number of Components Cannot Scale With The Number of Channels!

Integrated DWDM Filters

Arrays of Switches

Arrays of Variable OpticalAttenuators (VOAs)

Packaging andAssembly Difficult at High Channel Counts Integration Can Increase Performance and Reduce Cost


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Photonic Integrated Circuits Today Most of the Components Are Made From Individual Parts

Using Bulk Optics

Photonic Integrated Circuits (PLC) Combine ManyDifferent/Individual Parts Together in an Optical IntegratedCircuit (OIC)

The Technology Used Is a Waveguide-Based Planar LightwaveCircuit (PLC)

The PLCs Are Fabricated Using Semiconductor Equipment andExpertise

PLCs Have Been Made Using Waveguides Made From Silica on Silicon

Silicon Indium Phosphide

Polymers


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Passive

Splitting

Coupling Filtering (DWDM)

Tapping

Active - Slow

Switching (ms)

VariableAttenuation

Dispersion comp

Tunable filtering

(ms)

Active - Fast

Modulation (ns)

Switching (ns) Tunable filtering

Active All Optical

Amplification laser

Potentially betterforextremely high

speed modulation

>40GHz

Potential For Integration


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Materials For Optical Integration

Inorganic Crystals

Lithium Niobate

Excellent highspeed modulation>10GHz

Polarization andintegrationlimitations

Silica and Glass

Very low loss Inefficient for

active functions

Excellent forpassivecomponents likeDMUX

Thermo-optic

Polymers

Higherloss thanSilica

Moreefficient for

msec opticalswitches

Electro-optic

Polymers

High loss Potentially better

forextremely highspeed modulation

>40GHz Polarization

limitations

Semi-conductors

Potentially best forintegration of activeelements: lasers,detectors

Fiber interfaceproblems


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Waveguide Fabrication Process

Buried Channel Silica Waveguides


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Single Waveguide Parameters Waveguide Parameters

Refractive Indices Bottom Cladding

Core Top Cladding

Dimensions Width (CD)

Depth (Core Thickness)

Cladding Thickness

Effective Index (F) Other

WallAngle

Roughness

width

core

bottom cladding

Si Substrate

top claddingdepth


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Planar Lightwave Circuits

Buried Channel Silica Waveguides - Planar LightwaveCircuits (PLC) Are a Platform Technology

Arrayed Waveguide Gratings (AWG)

Optical Switch Arrays

Variable OpticalAttenuatorArrays (VOA)

Passive Waveguide

90 Bend

S Bend

180 Bend

Splitter

Directional Coupler

Taper

Optical Via

InPlane Mirror

Hybrid Waveguide Heated Waveguide

Coupler

Star Coupler

WaveguideElements


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100s of Waveguides

Arrayed Waveguide Grating

AWGs Represent a High Degree of Integration

100s of Precise Waveguide Elements Fabricated Together

Replace Many Individual Discrete Filters and Optics

First Proposed by Smit of Univ. Delft, 1988

Developed Over the Past 10 Years by Many Researchers

Universities, NTT, Lucent, PIRI, Hitachi and Others


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Building Blocks Now Future

Operation of Arrayed

Waveguide Gratings

Multi-wavelength at the inputport (1) Spreads out in the lens region (2)

Undergoes delays in each of the arrayed waveguide grating arms (3) Thephase tilt at the input to the second lens (4) depends on the wavelength Thisphase tilt affects how the light recombines in the second lens (5) in a process called

constructive interference Different wavelengths are thus directed to different output waveguides (6)


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AWG Parameters KeyAWG Parameters

Number of Channels (4 - 256)

Separation of Channels (400 GHz to 12GHz)

Optical Loss (fiber to fiber) b 7 dB

Isolation

Polarization Dispersion Loss (PDL) Passband Shape

Athermal Devices


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Wavelength

I

nsertionL

oss

Gaussian

AWG

Wideband

Flat-Top

AWG

AWG Passband Shape Depends on Input and Output

Waveguide Mode Field

Regular Shape PassbandGaussian Lowest Insertion Loss

Wideband or Flat-Top ShapePassband Relax Wavelength/Temp. Control

of Laser

Relax Wavelength/ TemperatureControl ofAWG

Widen Bandwidth in CascadedAWG e.g. Optical Add/Drop Multiplexers



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Worst

Within 0.2 nmITUpassbands Ave. Case Unit

CHANNEL INSERTION LOSS 6.1 6.4 dB

UNIFORMITY 0.5 dB

WIDEBAND 40-CHANNEL AWG CHANNEL RIPPLE 0.5 0.6 dBPDL 0.2 0.2 dB

ADJACENTISOLATION 33.0 29.3 dB

TOTAL ISOLATION 23.8 23.3 dB

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

1528 1532 1536 1540 1544 1548 1552 1556 1560

Wavelength (nm)

Inse

rtio

n

L

o

ss

(d


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Worst

Within 0.2 nmITUpassbands Ave. Case Unit

CHANNEL INSERTION LOSS 3.7 4.1 dB

UNIFORMITY 0.7 dB

NARROWBAND 40-CHANNEL AWG CHANNEL RIPPLE 1.0 1.1 dBPDL 0.2 0.3 dB

ADJACENTISOLATION 33.0 29.8 dB

TOTAL ISOLATION 22.3 22.0 dB

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

1528 1532 1536 1540 1544 1548 1552 1556 1560

Wavelength (nm)

Inse

rtio

n

L

o

ss

(d


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Isolation

Total Cumulative Isolation Includes Worst Case Power Inside ITU

Bands forAdjacent and Non-adjacent Channels forAll Polarizations

ITUBand

2

ITUBand

6

ITUBand

9

ITUBand

1

ITUBand

8

ITUBand

5

ITUBand

3

Use asreference

Useworst casepolarization

Non-Adjacent

Isolation

ITUBand

7

ITUBand

4

Adjacent

Isolation

AdjacentChannels



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Arrayed Waveguide Gratings

6 Inch Wafers Can Contain Many Photonic Circuits

And Can Be Individually Diced



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1

2

Optical Switch Example


1

2

1

2


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Thermo-optic Switch

Features:

Switches 1-3 Milliseconds

Compact

No Moving Parts

Arrays

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

0 5 10 15 20 25 30 35 40

Time (ms)

InsertionLoss(dB)

A

B

1

2



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Thermo-optic VOA

Features: Low Loss

Compact

Fast Response

Large Dynamic Range

Arrays

InputSignal

OutputPower

VOA



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Higher Levels of Integration

PLCs Enable the Integration of Multiple Optical Functionsin a Single Device Benefits

Improve Performance

Lower Cost

Smaller Footprint

Individual Modules Can Be Combined Into Subsystems VOA+ AWG

OADM

Frequency Synthesizers

Dynamic Gain Equalization



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Photonic Integration

Components Can Be Integrated Into PhotonicModulesAll on the Same Substrate (e.g. VOAsand AWG Multiplexers)

Such That the Input Optical Powers Are Dynamically Controlled

VOA1

3

2 VOA

VOA

4

VOA

n VOA

1 - n

MUX


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AWG

2x2 Switches

AWG

All-Optical Add/Drop Multiplexer

Dynamically Reconfigurable OADM

1 - n (DROP)

1 - n (ADD)

DMUX

1 - nMUX

1 - n



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OpticalAdd/Drop Multiplexer (OADM)



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OADM Wafer



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Example - OADM

Requires 18 or More Discrete Components

Requires 98 Fiber I/O and 32 Fiber Splices or More With VOAs, 32 Components, 130 I/Os and 64 Splices

Integrated Version Requires Only 34 Fiber I/Os.


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Conclusion

OpticalAdd/Drop MultiplexersAre An Important NetworkElement

Reconfigurable OADMsAre Enabling Elements in Metro Nets

Fully Reconfigurable OADMs Require Many Components PLC Integration Can Enable Such Complex Systems

Reduced Manufacturing Costs

Reduced Packaging and Assembly Costs

Reduced Size

Potentially Increased Reliability The First PLC Components Are On the Market

DWDMAWGs and Switches

real case studies of plc using sio2 on si

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