Jason Law shared insights into 400G datacenter optical architecture on JANOG48, incl 100G mainstream architecture and optional 200G solutions.

1. Outlook of
400G Datacenter Optical Architecture
2021 JANOG48 Presentation
Public. Copyright © GigaLight 2021. All rights reserved.

2. Market Forecast of transceiver in Data Center
2
Data Center Optical Module Rate Evolution
Demands of 400G optics start from 2019, growing fast.
4CH (4x100G) is the mainstream solution, 8CH (8x50G) is the option also.

3. 100G DC optical architecture in Japan
25G
100G
100G
100G
…
…
…
…
Core
Spine
Leaf
TOR
Sever
25G SFP28 AOC/DAC
100G QSPF28 SR4
100G QSFP28 CWDM4
100G QSFP28 LR4
100G QSFP28 ER4 Lite
3

4. 100G AOC/DAC
100km
Spine
Leaf
Leaf
TOR TOR
DWDM
2km
100m
20m
400G QSFP-DD FR4
400G QSFP-DD DR4
400G QSFP-DD SR8
400G DCO/ 800G DCO
200G breakout 1:2
DAC/ACC/AOC
100G Server
2021 ~
400G QSFP-DD FR4
400G QSFP-DD DR4
400G QSFP-DD SR8
400G DCO/ 800G DCO
100G AOC/DAC/ACC or AEC
400G to 2x 200G SR4/AOC
100G Server
2021 ~
100G SR2 AOC(SFP-
DD)/SFP-DD
100G Server
400G QSFP-DD FR4
400G QSFP-DD DR4
400G QSFP-DD SR4.2
400G DCO/ 800G DCO
2021 ~
4
400G DC optical architecture in TOP3 DC of CHINA

5. Design Schema of 400G Optics
5
4CH (4x100G PAM4) 8CH (8x50G PAM4)
400G FR4/LR4 400G DR4 400G FR8/LR8 400G SR8/PSM8

6. What is PAM4
6
✓ When the NRZ data rate is increased from 25Gb/s to 50Gb/s, the Nyquist frequency becomes
approx. 28GHz, at which the RF insertion loss is about 62dB for IEEE worst-case compliance
backplane traces.
✓ PAM4 has the advantage of packing 2 bits into a symbol, thus reduces the bandwidth by half. The Nyquist
frequency is now 14GHz and the insertion loss is reduced to approx.33dB, which can be compensated by
today's technology.

7. 50G PAM4 Vs 100G PAM4
Factor 8×50G PAM4 4×100G PAM4
Standard(LR8&LR4) IEEE 802.3bs 400GBASE-LR8 400G-LR4-10 100G Lambda MSA
Latency 8:8 DSP, without Gearbox, x usec 8:4 DSP, with Gearbox, xx usec
Transmission Distance
/km(LR8&LR4)
≤20km ≤10km
Power Consumption/Watts
(LR8&LR4)
≤12 ≤13
Laser Available Vcsel, DML, EML, SiPh EML, SiPh
Chipsets Resource Mature Being Mature
Current Cost $$$$ $$$
7

8. Flexible-400G Optics Portfolio
8*50G NRZ Structure
100km
Spine
Leaf
Leaf
TOR TOR
DWDM
2~10km
100m
20m
400G QSFP-DD LR8
50G PAM4 Structure
200G QSFP56 DR4/FR4
100G PAM4 Structure
400G CFP2 DCO /
400G QSFP-DD ZR+
200G/400G CFP2 DCO
200G SR4-4x50G AOC
200G DAC-4x50G DAC
400G AOC/DAC
1x4 Breakout
1x8 Breakout
Cost, Technology, Simplified, Reconfigurable
400G QSFP-DD DR4
400G QSFP-DD LR4
8

9. Global 200G Portfolio from Gigalight
Data Center
25G NRZ
Per Lane
50G PAM4
Per Lane
200G QSFP-DD 200G QSFP56
SMF
40KM
ER4
10KM
LR8 LR4
2KM
PSM8 FR4/uFR4
500M
PSM8 DR4
MMF
100M
SR8 / AOC SR4 / AOC
200G QSFP-DD AOC
(8X 25G)
200G QSFP-DD to 2x 100G QSFP28 AOC
(8X 25G)
200G QSFP-DD to 4x 50G QSFP28 AOC
(8X 25G)
200G QSFP56 AOC
200G QSFP56 to 2x 100G QSFP28 SR2
200G QSFP56 to 4x 50G SFP56 SR
25G NRZ 50G PAM4

10. Next Generation 400G QSFP112-- IEEE802.3ck
10
CDR/DSP
X4
TIA X4 PD X4 RX x4
CDR/DSP
X4
LD X 4 Laser X4 TX x4
TX x 4
RX x 4
100G PAM4
Optical
Interface
100G PAM4
4*100G PAM4 （4:4） - 400G QSFP112 xR4
The next 400G QSFP112, without Gearbox, Solve the channel inconsistency problem
The problem of optical nonlinearity need be solved by Silicon Photonics modulation and
improved EML technology
Current 400G QSFP-DD Gearbox 8:4, cause of the data rate revising, bring the problem of COM
Channel inconsistency and imbalance problems, nonlinear problems in optics.
Conclusion: QSFP112 improve the reliability of long time transmission

11. About GigaLight
Moscow
Shenzhen
Beijing
Shanghai
corporate HQ
R&D Center
Wuhan
Sales & Support
Sales & Support (in preparation )
Taiwan
Bangalore
EU
HQ and Marketing
R&D, Operation and Sales
Wuhan R&D. Center
1
2
3
4
2006
E s t a b l i s h e d
116 million RMB
R e g i s t e r e d c a p i t a l
430 em ploye es in total, 80+
R&D and engineers
N u m b e r o f
e m p l o y e e s
Total area of manufacturing
and R&D center is over 25,000 ㎡
S p a c e
HQ: Shenzhen, China
R&D Center: Shenzhen, Wuhan
Factory: Shenzhen, Yancheng
Sales&Support: Shenzhen, Shanghai, Beijing, Taiwan, Bangalore, Moscow, EU
Yancheng
11

12. GigaLight Product Segment
50G/100G/200G/400G DAC
Datacenter interconnection
100G/200G/400G TRCV&AOC&MPO
25G IT TRCV/ xWDM Passive
/100G/200G/400G TRCV
5G Carrier network
interconnection
10G/40G/100G TRCV
100G/200G DCO & xWDM Passive
Metro WDM and
Coherent communication
3G/12G-SDI TRCV&Extender
HD video interconnection
MPO/MTP/Patch cord cabling
Optical Cables
Server Highspeed
Copper interconnection
12

13. THANK YOU FOR ATTENETIONS!
2021 JANOG48 Presentation
Public. Copyright © GigaLight 2021. All rights reserved.