Low Power DSP and Photonic Integration in Optical Networks MF... · Low Power DSP and Photonic Integration in Optical Networks ... Coherent CFP enabled by LP-DSP • LP-DSP integrated

Atul Srivastava

CTO, NTT Electronics - America

Low Power DSP and Photonic Integration in

Optical Networks

Market Focus ECOC 2014

NTT Electronics Corp. ©2013 – proprietary & confidential

Outline

• 100G Deployment

– Rapid Growth in Long Haul

– Role of Modules

• New Low Power 100G DSP

– Based on 20nm CMOS

– Versatile: Many Applications

– Pluggable Modules (CFP, CFP2…)

• Integration in Optical Components

– InP Devices

– Si Photonics

– Compact Tx/Rx with DSP assist

• Discussion

2


100G Deployment Trends

3 Exponential Growth: Doubling 1.5-2 years


100G Coherent Metro Networks

4

Metro Regional

Metro Core

Long-Haul

Metro Access

• Long-Haul >1500, 6-8 ROADMs

• Metro-Regional

500-1000km; 16 ROADMs

• Metro-Core 100-500km; 24 ROADMs

• Metro-Access

40-100km

Typical Optical Specs: 16dB OSNR, 15,000ps/nm dispersion, 12ps PMD

Cost, Power and Size of module are key metrics for 100G Metro


100G Modules and Line cards: Lower Power and

Smaller Size Enabling higher card density

2012

100W

Size (Smaller)

Power Consumption

5

2016

45W

OIF Gen 1 5x7 MSA 80W

OIF Gen 2 4x5 MSA 45W

CFP <30W CFP2 ACO 12W

2014

Module Power

dominated by

electronic

components

Lower Power DSP

Module Size determined by

optical

components

Tx & Rx

More Integration

NTT Electronics Corp. ©2013 – proprietary & confidential 6

100G Transceiver Module/DSP Power Dissipation

5”x7”

4”x5”

CFP 40nm CMOS

28nm

20nm


Gen-2 Gen-1

Trends on Coherent Transceiver MSAs

7

Multi-haul, Telecom

Non-LH Telecom/Datacom

5’’x7’’

CFP

DSP

Rx

Mo

d.

Mo

d. DSP

Rx

Mo

d.

DSP

Rx

4’’x5’’

DSP

CFP2

ACO

2011 2013 2015~2017

OIF Gen-2 IA

Editor: Atul Srivastava

Long-haul, telecom

NEL

DSPs



NLD0629 100G DSP

• 40-nm CMOS

• External transmit MUX, external framer ASIC

9

100G

Optical

Front-End

SD-FEC

encoder

SD-FEC

Decoder

(FEC)

Fixed

Equalizer

(FEQ)

Adaptive

Equalizer

(AEQ)

4ch

A/D

converter

I/O

IF

I/O

IF

Other

Rx

DSP

TX

DSP

I/O

IF

MUX

IC

Dual

I-Q

Mod.

XI

XQ

YI

YQ

XI

XQ

YI

YQ

Framer

IC


NLD0640 100G LP-DSP

• 20-nm CMOS • Internal 4x DAC, internal framer with EFEC • 70%-less power consumptions and footprint

– If compared with 40-nm three-chip solution

10

100G

Optical

Front-End

SD-FEC

Encoder

SD-FEC

Decoder

(FEC)

Fixed

Equalizer

(FEQ)

Adaptive

Equalizer

(AEQ)

4ch

A/D

converter

I/O

IF

I/O

IF

Other

RX

DSP

Line estimation

TX

DSP

4ch

D/A

converter

Dual

I-Q

Mod.

XI

XQ

YI

YQ

XI

XQ

YI

YQ

Fra

me

r

Lower Power <20W with 20nm


Target Applications

11

Long Haul (LH)

~ 2,000 km

p2p DWDM

Metro-Regional (MR)

~ 600 km

ROADM Ring

Metro-Access (MA)

~ 600 km

p2p WDM

ZR

~ 100 km

Dark Fiber

Data Center

Data Center

Gen

-1 D

SP

Gen

-2 L

ow

Po

wer

DS

P

2012 ~

2013 ~

2014 ~

2014 ~


Specifications selectable function matrix

12

SD-FEC

(LDPC)

7%

HD-FEC

CD compensation

(ps/nm)

OFF

55,000

20,000

10,000

2,000

Nyquist

filter

ON

OFF

Client

100GbE

OTU4

ON

OFFG-FEC

E-FEC

Items SpecificationModulation format DP-QPSK

Nyquist filter ON / OFFSignal bit-rate(Selectable)

127.2 Gb/s (OTU4V mode)111.8 Gb/s (OTU4 mode)

Chromatic dispersion compensation +/-55,000 ps/nmNet coding gain 11 dB (SD-FEC + E-FEC)

Dispersion estimation time 17 msecPolarization tracking speed 50 KHz

Frequency offset compensation +/- 5 GHzClient signal (Selectable) 100GbE CAUI / OTU4 OTL4.10

100GE

G-FEC OFF

2,000

OFF

Short range (100 km)

E-FEC ON

20,000 OUT4 OFF

Metro access (1,000 Km)


Lower Power by 20nm and function selection

13

Lower Power < 20W with 20nm


Current Solutions for Coherent MSA

14

• 40nm discrete three-chip configuration

– 100G OTN Framer,

– 100G DSP, and

– Transmit Mux


Coherent CFP enabled by LP-DSP

• LP-DSP integrated the three-chip functions

– 70%-less power dissipations

– 70%-less foot print

• If compared with three-chip solutions

15


LP-DSP mounted CFP with InP Modulator

16

THPDP1-4:OECC2014 PDP

SD-

FEC

Modulator

Controller MDIOinterface

TX Output(Optical)

IntegratedReceiver

10

10

10 Gbps x 10

Rx Input(Optical)

OTU4/100GE

DAC

ADC

ModulatorDrivers

Coherent

DSP

Tu

nab

le

Laser

Fra

mer

InP DP-IQ

MDIO: Management Data Input/Output

Photo courtesy of

http://www.oecc-acoft-2014.org/wp-content/uploads/THPDP1-4oecc2014Abstract00724.pdf




InP-based DP-IQ modulator

17

-30

-25

-20

-15

-10

-5

0

-4 -2 0 2 4

XI XQ YI YQ

Push-pull driving voltage [V] N

orm

. ou

tpu

t p

ow

er [

dB

]

p/2

p/2

In

XI

XQ

YI

YQ

PMF

SMF

Out

• Differential drive

• SMT I/F for RF

• FPC I/F for DC

• Bias voltage: < 10 V

• Vp: 1.9 V@DC, < 2.5 V @ 32 GBaud

• Module size: 12×39 x 6.5 mm

Modulator configuration InP DP-IQ modulator

(12 x 39 x 6.5 mm)

Extinction characteristics


Tunable laser: micro ITLA

18

Micro-iTLA (20 x 35 x 6.9 mm)

Compact tunable laser module (8 x 15.25 x 6.2 mm)

Fiber

Wavelength Locker Tunable DFB Laser Array

PD2

TEC1

Etalon Filter

PD1

TEC2

• Compact laser module installed in OIF

compliant micro-iTLA

• Use of stable DFB array-type LD

• Output power: 16 dBm

• Spectral linewidth: < 300 kHz

Spectral linewidth @ ITU-T Grid

PETRA Confidential


ICR (Integrated coherent receiver)

19

• OIF compliant (type 2)

• Silica-based PLC DPOH (Dual

Polarization Optical Hybrid)

• Hybrid integration of photodiodes via

micro lens array

• Wide input power dynamic range with

integrated VOA

Module configuration

Waveguides

4-ch PD array

Micro-lens array

Silica PLC

Side view

Signal line

TIA

Base

Integrated coherent receiver (16 x 30 x 5 mm)

PETRA Confidential

Subcarrier


Coherent detection with ICR

20

LO power = 13 dBm OSNR = 16 dB

PETRA Confidential


Eye-diagram and consternation

21

X Pol.

Y Pol.

X Pol.

Y Pol.

OSNR: 30dB (0.1nm resolution)

Real-time received constellations Transmitted optical waveform


Real-time measured post-FEC BER vs. OSNR

22


Si photonics

• Leverage CMOS facilities

Ecosystem including ext. CMOS fab is to be established.

Good mass producibility: wafer size is 8 or 12 inches

• Shrink size of optical devices

Smaller optical circuits (R~5mm)

Larger propagation loss, phase error,

– and polarization dependence must be handled

Coupling with optical fiber is challenging

• Can integrate active elements such as modulator and photodiode

delta = 41.32%, 0.33166x0.33166

-10 -5 0 5 10-10

-5

0

5

10

delta = 0.3%, 7.2x7.2

-10 -5 0 5 10-10

-5

0

5

10

SM fiber Si nanowire

SiP InP Silica PLC

Passive Yes Yes Yes

PBS, PR Yes Difficult Yes

Modulator Yes Yes Hybrid

PD Yes Yes Hybrid

Laser Hybrid Yes Hybrid

TO effect ~10-4 /T ~10-4 /T ~10-5 /T


Electronics integration with Si photonics

Photonics: WDM filter array and Ge PD array Electronics: TIA integration by flip-chip bonding

100G one-chip Rx

25 G x 4-ch TIAs

4l x 25G TIA output of 25 G IMDD (PRBS 231-1) PD input: -10 dBm K. Takeda, GFP’14

HF evaluation set-up

HF probe HF probe CPW

CPW chip

PIC wafer


Compact Optical Tx and Rx …DSP Assist

DSP

PBC

AD

C

DAC PBS

LD

LD

Tx

Rx

Coupling

loss

Chirp

Phase error

Extinction

ratio

Loss

imbalance

Vpi

Coupling

loss

Coupling

loss

Performance enhancement by DSP


26

Thank you

Low Power DSP and Photonic Integration in Optical Networks MF... · Low Power DSP and Photonic Integration in Optical Networks ... Coherent CFP enabled by LP-DSP • LP-DSP integrated

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