1. Introduction

Short-distance high-speed interconnection serves as the fundamental support for efficient data center operations. Multimode fiber (MMF), with its cost and power consumption advantages, has become the mainstream transmission medium for such scenarios.

As the primary options for MMF, OM4 and OM5 directly determine link transmission performance, scalability potential, and deployment costs through their technical characteristics. The selection process requires precise alignment with bandwidth requirements, transmission distance, and future upgrade plans—particularly clarifying their differences in key dimensions such as technical specifications and SWDM (Shortwave Wavelength Division Multiplexing) compatibility. This article will systematically explore technical parameters, application scenarios, and core technologies to provide professional guidance for OM4 and OM5 selection in data center short-reach links.

2. Technical Specifications of OM4 and OM5 Multimode Fiber

2.1 OM4 Fiber Technical Specifications

OM4, a mainstream MMF model, focuses on short-reach high-speed transmission.

Category	Technical Parameters
Standard	IEC 60793-2-10
Physical Structure	• Core: 50μm • Cladding: 125μm
Bandwidth	• EMB @850nm: ≥4700 MHz·km • EMB @1300nm: ≥1500 MHz·km
Attenuation	• 850nm: ≤3.5 dB/km • 1300nm: ≤1.5 dB/km
Transmission	• 100G-SR4: 150m • 40G-SR4: 150m • 25G-SR: 300m
Application	Short-range interconnects in medium-to-large data centers.

2.2 OM5 Fiber Technical Specifications

OM5, also known as Wideband Multimode Fiber (WBMMF), represents an optimized upgrade from OM4. The enhanced attenuation stability across the broad wavelength band enables adaptation to multi-wavelength parallel transmission scenarios, providing greater scalability for data center bandwidth upgrades.

Category	Technical Parameters
Standard	IEC 60793-2-10
Physical Structure	• Core: 50μm • Cladding: 125μm
Bandwidth	• EMB @850-950nm: All wavelengths ≥4700 MHz·km
Attenuation	• 850nm: ≤3.0 dB/km
Transmission	• 100G-SR4: 150m • 25G-SR: 300m
Key Advantage	Supports multi-wavelength transmission over a single fiber via SWDM

2.3 OM4 vs. OM5 Core Technical Differences (2026 Standards)

Parameter	OM4	OM5
Release Year	2009	2016
Outer Jacket Color	Aqua/Violet	Lime Green
Fiber Diameter	50μm core/125μm cladding	50μm core/125μm cladding
Operating Wavelengths	850nm, 953nm (dual)	850nm, 880nm, 910nm, 940nm (multi)
Light Source	VCSEL	VCSEL
Bandwidth-Distance Product	4700 MHz·km @850nm	>3500 MHz·km (per wavelength)
Max Data Rate	100Gbps	400Gbps
Jacket Material	Ge-doped core + Low-index cladding	Ultra-bend insensitive (≤7.5mm radius)
Primary Applications	• High-density data centers • Cloud infrastructure	• SWDM4 systems • 5G fronthaul

3. OM4 vs. OM5 Fiber Comparison

3.1 Application Scenarios

Fiber Type	Key Applications	Technical Advantages
OM4	• Medium/large data center interconnects (≤100G) • Cost-sensitive cloud server-switch links • Enterprise 25G/40G deployments	• Proven reliability (17+ years in service) • 40% lower cost vs. OM5 • 300m reach @25G-SR
OM5	• Hyperscale DCs (400G/1.6T ready) • HPC clusters • 5G fronthaul with SWDM4 • Space-constrained edge DCs	• 75% fiber reduction via SWDM4 • Bend-insensitive design (7.5mm radius) • Future-proof to 2029 standards

3.2 What is SWDM

SWDM (Short Wavelength Division Multiplexing) is a bandwidth expansion technology for multimode fiber. It divides the 850nm-950nm wavelength band into four independent sub-wavelengths (typically 850nm, 880nm, 910nm, and 940nm), enabling parallel transmission of multiple signals over a single multimode fiber.

Standardized by the SWDM MSA protocol, this technology reduces the number of fiber cores required for 40G/100G transmission by 75%, significantly lowering data center cabling costs and space requirements. Leveraging cost-effective VCSEL light sources, SWDM enables seamless speed upgrades from 10G/25G to 40G/100G without modifying existing cabling infrastructure. The 100G SWDM4 solution achieves transmission distances exceeding 150 meters.

Its core value lies in overcoming the fiber resource constraints of multimode fiber parallel transmission. The wide bandwidth characteristics of OM5 fiber perfectly match SWDM’s full-band transmission requirements. Together, they form the key solution for high-speed upgrades over multimode fiber.

4. Multimode Fiber Development Trends

Driven by demands from AI computing clusters and cloud computing, multimode fiber is evolving toward wider bandwidth, higher speeds, and lower energy consumption. Leveraging its full-band compatibility across 850nm-950nm, OM5 fiber will accelerate its market penetration, becoming the mainstream choice for new hyperscale data centers and enabling upgrades to 400G and even 1.6T high-speed transmission.

The deep integration of SWDM technology with OM5 will emerge as a core trend. Multi-wavelength multiplexing will further enhance fiber bandwidth density, alleviating fiber resource constraints in data centers. Concurrently, multimode fiber will continuously optimize attenuation characteristics and thermal stability.

Aligned with green and low-carbon demands, this will drive the adoption of eco-friendly products like halogen-free jackets. Furthermore, to ensure upgrade compatibility, future multimode fiber products will enhance compatibility with existing OM4 links and VCSEL optical modules. Industry standards will also continue to evolve around higher effective mode bandwidth (EMB) and laser optimization performance, building a more robust high-speed multimode transmission ecosystem.

5. Frequently Asked Questions (FAQ)

1. Introduction

With the explosive growth in data center bandwidth demands and the large-scale deployment of 5G technology, high-density, low-loss fiber optic connections have become a core requirement for upgrading communication infrastructure. MPO and MTP connectors, as key components for high-density fiber optic connections, are widely used in various high-speed transmission scenarios. Although the two share a common technical lineage, they exhibit significant differences in performance, compatibility, and other dimensions, directly impacting the effectiveness and stability of low-loss cabling systems.

2. Fundamentals of MPO and MTP Connectors

2.1 MPO Connectors

The MPO (Multi-Fiber Push-On) connector is a multi-fiber connector based on the IEC 61754-7 standard, characterized by its ability to achieve parallel connections for multiple fibers through a single connector assembly. It employs precision ceramic ferrules for alignment and is commonly available in 12-, 16-, and 24-fiber configurations, catering to high-density scenarios where traditional connectors like LC or SC fall short. The push-pull design enhances operational convenience, but due to limitations in early standards, MPO connectors face challenges in insertion loss stability and repeated mating cycles. They are primarily used in medium-to-low-speed transmission and cost-sensitive cabling applications.

2.2 MTP Connectors

The MTP connector, developed by US Conec, is an enhanced version of the MPO connector and remains fundamentally compliant with MPO standards. Key improvements include:

• High-precision polished fiber arrays
• Floating ferrule design for better alignment
• Reinforced housing for mechanical stability

Available in 12-, 24-, and 48-fiber variants, MTP connectors offer lower insertion loss, superior repeatability, and higher durability. They also feature better environmental resistance, making them ideal for high-speed transmission and low-loss cabling systems, particularly in high-end data centers.

2.3 Core Differences: MPO vs. MTP

The primary distinctions between MPO and MTP lie in precision, performance, and manufacturing:

• Precision: MTP uses higher-tolerance ceramic ferrules and fiber arrays, reducing alignment errors by over 30% compared to MPO.
• Performance: MTP achieves lower insertion loss (≤0.3 dB vs. MPO’s ≤0.5 dB) and longer lifespan (1,000+ cycles vs. MPO’s ~500).
• Design: MTP incorporates advanced features like floating guide pins and dust caps, while MPO adheres to basic standardized designs.
• Compatibility: MTP is backward-compatible with MPO, but not vice versa.
• Cost: MTP is more expensive due to its enhanced engineering.

3. Core Technologies for Low-Loss Cabling

3.1 Factors Affecting MTP/MPO Insertion Loss

The insertion loss of MTP/MPO connectors is primarily influenced by device characteristics, installation practices, and environmental conditions.

3.1.1 Device Factors

Fiber end-face polish quality and the positioning tolerance of ceramic ferrules directly determine core alignment accuracy. MTP’s superior polishing and tighter tolerances (as previously discussed) minimize these losses.

3.1.2 Installation Factors

Axial misalignment during mating and excessive bend radius in fiber jumpers induce micro-bending losses. Repeated insertions beyond rated cycles (e.g., >500 for MPO, >1,000 for MTP) accelerate end-face wear.

3.1.3 Environmental Factors

High temperature/humidity can oxidize metal components or cause condensation on end-faces. Dust contamination leads to scratches, significantly increasing insertion loss and requiring stringent control, particularly in low-loss cabling systems.

3.2 Key Advantages of MTP/MPO

MTP/MPO technology excels in density, loss control, and compatibility.

3.2.1 High Density

Supports 12–48 fibers in a single connector, reducing cabling space by >60% versus single-fiber solutions (e.g., LC/SC), ideal for dense data centers.

3.2.2 Low-Loss Performance

MTP achieves ≤0.3 dB insertion loss; MPO (≤0.5 dB) still outperforms traditional multi-fiber options. Compatible with low-loss fiber jumpers for end-to-end optimized links.

3.2.3 Compatibility & Scalability

MTP is backward-compatible with MPO, enabling seamless upgrades. Supports cross-vendor interoperability, reducing maintenance costs.

3.3 MTP/MPO 12-Fiber vs. 16-Fiber Configurations

The choice between 12-fiber and 16-fiber MTP/MPO depends on application.

3.3.1 12-Fiber (MTP/MPO-12)

Used in 4-lane transceivers (e.g., 100G-SR4, 400G-SR4), where 8 fibers transmit data (4Tx + 4Rx) and 4 remain unused.

3.3.2 16-Fiber (MTP/MPO-16)

The 16-fiber configuration differs significantly, typically serving 8-channel modules like 400G-SR8 and 800G-DR8. Here, all 16 fibers are utilized for signal transmission, with no unused fibers. Both densities feature distinct connector designs to facilitate user differentiation and proper application.

4. Frequently Asked Questions (FAQ)