112 Gbps PAM4 is a widely adopted data transmission standard and modulation scheme used in high-speed networking and data centers to achieve aggregate data rates of 400 GbE (4x112G) and 800 GbE (8x112G). It enables faster data transfer over existing infrastructure like copper cables and silicon photonics. 

Pulse Amplitude Modulation 4-Level (PAM4) Explained

PAM4 is a signal encoding technology that uses four different voltage (amplitude) levels to transmit data, as opposed to the two levels (on/off) used by traditional Non-Return to Zero (NRZ) signaling. 

• Data Representation: With four levels, each signal symbol can represent two bits of logic (00, 01, 10, or 11).
• Doubled Bandwidth: This means PAM4 can transmit twice the amount of data in the same amount of time (baud rate) compared to NRZ. A 56 gigabaud (GBd) PAM4 signal effectively achieves a data rate of 112 Gbps (56 GBd * 2 bits/symbol). 

Key Characteristics of 112 Gbps PAM4 Technology

• Industry Standard: 112 Gbps PAM4 is specified by industry standards bodies like the Optical Internetworking Forum (OIF) CEI-112G and IEEE P802.3ck to ensure interoperability across different vendors and systems.
• Applications: It is primarily used in high-performance computing (HPC), artificial intelligence/machine learning (AI/ML) clusters, and data center networks for high-speed interconnects like optical transceivers, active copper cables (ACCs), and backplanes.
• Technical Challenges: While offering speed benefits, PAM4 signals are more susceptible to noise and require more complex circuitry, such as digital signal processors (DSPs) and advanced equalizers, to recover the signal accurately due to the smaller voltage differences between the four levels.
• Connectivity Solutions: Various physical interconnect products, including connectors, high-speed twinax cables (often using “Flyover” technology to bypass lossy PCBs), and silicon photonics systems, have been developed to support reliable 112 Gbps PAM4 performance. 

This technology is crucial for enabling the next generation of network speeds and densities as system designers push for higher performance within limited physical space and power budgets. 

This leads us to a Product Focus article at Optical Connections journal

112Gbps-PAM4 Connectivity – Different Solutions for all Applications

Created January 16, 2024

The market requirements of 112Gbps-PAM4 connectivity for optical transceiver pluggable modules are constantly increasing. Yamaichi Electronics is a leading company for 112G high speed connectors. Our portfolio includes also benchmark breaking signal integrity connectors up to 112G-PAM4 and soon 224G-PAM4. Yamaichi plays an important role in the 112G and 224G standardisation and provided many concepts for MSAs.

Yamaichi Electronics offers 112Gbps-PAM4 for: SFP, DSFP, NGSFP-DD, QSFP, QSFP-DD, OSFP, OSFP-XD, CFP and more. Also available are our modular mezzanine connector and our high-speed jumper cable interconnect product.

• SFP and DSFP up to 112Gbps-PAM4 per differential pair.
• QSFP and QSFP-DD host connector up to 112G-PAM4 per differential pair.
• OSFP and OSFP host connector up to 112G-PAM4 per differential pair.
• High speed and high current capacity CFP2 are available.
• 112Gbps-PAM4 Mezzanine Connectors – YTM Series with highest density.
• 112Gbps-PAM4 high-speed jumper cable interconnect product with stable data transmission.

Visit us at ECOC 2023 in Glasgow, Scotland, from 02 through 04 October at stand no. 7. We will be demonstrating the excellent SI performance of our 112G www.yamaichi.de/connectorsolutions/ pluggable-moduleconnectors

This article was written
by Optical Connections News Team

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