Why AI Data Centers Need Multimode MTP®/MPO APC Connector Cabling Solutions

The Growing Demand for High-Speed Connectivity in AI

AI workloads, particularly those involving large language models (LLMs) and deep learning, require massive parallel data transfers between GPUs and TPUs at speeds of 100G, 400G, and beyond. To support these demands, data centers are transitioning to PAM4 (Pulse Amplitude Modulation 4-level) signaling, which doubles the efficiency of traditional NRZ encoding. However, PAM4's narrower eye diagram makes it highly sensitive to signal degradation—especially from reflections in fiber optic connections.

The Challenge: Signal Integrity at High Speeds

1. PAM4's Sensitivity to Reflections

PAM4's four-level signaling (00, 01, 10, 11) enables higher data rates but is more prone to interference. Even minor reflections—caused by dust, scratches, or imperfect connectors—can scatter light back to the transmitter, distorting signals and increasing bit error rates (BER). This leads to:

• Retransmissions, increasing latency

• Longer AI training cycles, raising operational costs

• Reduced efficiency in high-performance computing (HPC) environments

Figure 1: PAM4's narrower eye diagram makes it more vulnerable to noise than NRZ.

2. Limitations of UPC endface Connectors

Most multimode MTP®/MPO fiber cables (e.g., 12/24-fiber variants) use UPC (Ultra Physical Contact) polishing, which has a slight curvature to reduce reflections. While effective for older NRZ-based networks, UPC endface struggles with PAM4's demands because:

• Multimode fibers have larger cores, allowing multiple light modes that create complex reflections.

• UPC's flat polish doesn't fully eliminate back reflections at 100G/400G/800G speeds.

• Higher return loss increases the risk of signal distortion.

The Solution: APC Endface Connectors for AI-Optimized Networks

How APC Reduces Reflections

APC (Angled Physical Contact) connectors feature an 8° angled polish (vs. UPC's flat surface). This design:

• Redirects reflected light into the cladding, where it's absorbed instead of bouncing back.

• Lowers return loss, improving signal integrity for PAM4 modulation.

• Supports higher data rates (400G/800G) with minimal interference.

Figure 2: APC's angled end-face prevents reflections from reaching the transmitter.

APC vs. UPC: Key Differences

T&S's Multimode MTP®/MPO APC Solutions for AI Data Centers

To meet the needs of AI-driven infrastructures, T&S offers high-performance APC optical fiber solutions, including:

1. MTP®/MPO APC Cables

• Low-reflection design for stable 400G/800G transmission

• OM4/OM5 compatibility for future-ready scalability

• Custom configurations (8/12/16/24/36-fiber or more fiber count options)

2. Recommended Products

Conclusion: Future-Proofing AI Data Centers with APC

As AI workloads push data rates beyond 400G, minimizing reflections is critical. T&S’s MTP®/MPO APC fiber solutions ensure:

• Lower return loss for cleaner PAM4 signals

• Higher reliability in dense AI/ML environments

• Seamless compatibility with InfiniBand and Ethernet standards

Upgrade to APC today—optimize your AI infrastructure for speed and stability. Visit link below to explore the right products to upgrade your MPO/MTP® cabling projects: https://www.china-tscom.com/products/mpo-mtp-cable-assembly/