OS2 vs OM1 vs OM2 vs OM3 vs OM4 vs OM5 Fiber Types: Complete Comparison Guide

What Are OS2 and OM Fiber Types?

Fiber optic cables are broadly classified into single-mode fiber (SMF) and multimode fiber (MMF). OS2 is the most common single-mode fiber standard, while OM1 through OM5 are different grades of multimode fiber. "OM" stands for "Optical Multi-mode," defined by the ISO/IEC 11801 standard, which identifies the bandwidth performance and transmission capabilities of multimode fibers.

Choosing the correct fiber type is critical for network performance, cost efficiency, and future scalability. This guide provides a comprehensive comparison of OS2, OM1, OM2, OM3, OM4, and OM5 fiber types across all key parameters.

OS2 Single-Mode Fiber: The Long-Distance Champion

OS2 is the predominant single-mode fiber standard, compliant with ITU-T G.652.D specifications. With a tiny 9µm core diameter, it allows only a single mode of light to propagate, virtually eliminating modal dispersion and enabling extremely long transmission distances and virtually unlimited bandwidth.

OS2 Key Specifications:

• Core Diameter: 9/125µm
• Jacket Color: Yellow
• Light Source: DFB/FP Laser Diode
• Operating Wavelengths: 1310nm / 1550nm
• Attenuation: ~0.35 dB/km @1310nm, ~0.22 dB/km @1550nm
• 10G Reach: 10-100+ km
• 40G/100G Reach: 10-40 km (with LR/ER/DR optics)

Applications: Telecom backbone networks, metropolitan area networks (MANs), campus backbones, data center interconnect (DCI), long-haul WAN links. If your link exceeds 550 meters or you plan future 400G/800G upgrades, OS2 is the only viable choice.

OM1 Multimode Fiber: Legacy Systems Only

OM1 (1989) is the earliest multimode fiber standard, featuring a large 62.5µm core and using LED light sources. With a low bandwidth of 200 MHz·km at 850nm, it is now deprecated by industry standards and not recommended for new installations.

OM1 Key Specs: Orange jacket, 62.5/125µm core, 10G only 33m, 1G up to 275m. Still found in legacy 100Mbps Ethernet networks, but being phased out.

OM2 Multimode Fiber: Early 50µm Standard

OM2 (1998) reduced the core to 50µm and improved bandwidth to 500 MHz·km, supporting 1G up to 550m. However, like OM1, it uses LED sources and cannot support 25G or higher-speed networks.

OM2 Key Specs: Orange jacket, 50/125µm core, 10G only 82m. Limited deployment in small enterprise networks. Not recommended for new projects.

OM3 Multimode Fiber: Laser-Optimized 10G Standard

OM3 (2003) is laser-optimized multimode fiber (LOMMF), specifically designed for 850nm VCSEL sources. Its manufacturing process eliminates the center index defect found in OM1/OM2, enabling significantly higher bandwidth performance.

OM3 Key Specifications:

• Core Diameter: 50/125µm
• Jacket Color: Aqua
• Light Source: 850nm VCSEL
• Effective Modal Bandwidth: 2000 MHz·km @850nm
• 10G Reach: 300m
• 40G Reach: 100m (SR4)
• 100G Reach: 70m (SR4)

Applications: Enterprise data centers, campus backbones, small-to-medium data centers. OM3 offers the best cost-efficiency for 10G deployments.

OM4 Multimode Fiber: High-Performance Data Center Standard

OM4 (2009) is an enhanced version of OM3, doubling the effective modal bandwidth to 4700 MHz·km. It is the current mainstream recommendation for data center and enterprise network multimode fiber deployments.

OM4 Key Specifications:

• Core Diameter: 50/125µm
• Jacket Color: Aqua or Erika Violet
• Light Source: 850nm VCSEL
• Effective Modal Bandwidth: 4700 MHz·km @850nm
• 10G Reach: 400-550m
• 40G Reach: 150m (SR4)
• 100G Reach: 150m (SR4)
• 400G Reach: 50-100m (SR8)

Applications: High-performance data centers, financial trading networks, enterprise campus backbones, 40G/100G network deployments. OM4 provides the best balance of performance and cost for 80% of enterprise networks.

OM5 Multimode Fiber: Wideband SWDM Standard

OM5 (2016), also known as Wideband Multimode Fiber (WBMMF), is the latest generation of multimode fiber. It matches OM4 bandwidth at 850nm but adds a bandwidth requirement at 953nm (2470 MHz·km), enabling Short Wavelength Division Multiplexing (SWDM) technology.

OM5 Key Specifications:

• Core Diameter: 50/125µm
• Jacket Color: Lime Green
• Light Source: SWDM VCSEL
• Wavelength Range: 850nm - 953nm (4 channels)
• 10G Reach: 550m
• 40G SWDM4 Reach: 240m
• 100G SWDM4 Reach: 150m
• 400G Reach: 100m

OM5's key advantage is SWDM, which transmits 4 wavelengths (850nm, 880nm, 910nm, 940nm) over a single fiber pair, quadrupling capacity and reducing fiber count.

Applications: High-density data centers planning 400G/800G, fiber-constrained installations, SWDM-based deployments.

Complete Comparison Table

How to Choose the Right Fiber Type

By Distance

• Over 550m: OS2 single-mode fiber is mandatory
• 100-550m: OM3 (10G@300m) or OM4 (10G@550m)
• Under 100m: OM3/OM4/OM5 all work; OM3 is most cost-effective

By Network Speed

• 10G: OM3 is best value (300m), OM4 for longer reach (550m)
• 40G/100G: OM4 is mainstream (150m SR4), OM5 for SWDM benefits
• 400G/800G: OS2 is safest long-term; OM5 for short-reach SWDM

New Installation Recommendations

• Data Center Backbone: Start with OM4, deploy OS2 for backbone links
• Enterprise LAN: OM3/OM4 for 10G-40G needs
• Telecom/ISP Long-haul: OS2 is the only choice
• FTTH Access: OS2 single-mode fiber

Avoid OM1 and OM2 for new installations as they cannot support modern high-bandwidth requirements.

Langzhi Technology Fiber Product Recommendations

Langzhi Technology offers a complete range of fiber optic products including OS2/OM3/OM4/OM5 fiber patch cables, SFP/SFP+/QSFP optical transceivers, GPON/EPON OLT equipment, and ONU/ONT terminals for all your fiber network needs from data centers to FTTH. Contact us for professional fiber selection advice!