How to Choose QSFP28 Optics for 100GbE Deployment?

As we know, QSFP28 is considered to be the mainstream form factor in today’s 100GbE optics market. There are many products with QSFP28 form factor including DAC (Direct Attach Copper) cables, AOCs (Active Optical Cables), and transceivers with various interface options, like SR4, LR4, PSM4, CWDM4, etc. 

Among these QSFP28 products, which one is the best for your data center 100GbE deployment? The selection of the most suitable 100G QSFP28 product depends on a few factors. The most basic factors may be the transmission distance you may want to reach and the cable types you plan to use.

100G-distance

Copper DAC Used Inside Racks: 1-5 m

QSFP28 passive DAC products including QSFP28 to QSFP28 DACs and QSFP28 to 4x SFP28 DACs are ideal to use for reaches within 5 m, providing a very cost-effective I/O solution for 100GbE connectivity. Instead of discrete components, QSFP28 DACs offer a complete cable assembly for short-distance connectivity in a cost-effective manner. If your 100GbE deployment is within 5m intra racks, the DAC is ideal for you.

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 100GBASE-QSFP28-LR4-10km Optical Transceiver Module

Multimode Fiber Use Between Switches: 5-100m

For 100GbE cabling with multimode fiber between switches, there are two options. One is to use QSFP28 AOC which is the best fit for 3-20 meters. And the other option is to use a QSFP28 SR4 transceiver with 12-fiber MTP OM3/OM4 cable. SR4 with 12-fiber OM4 MTP fiber cable can support reaches up to 100 m. If you want to use multimode fiber for connectivity, you could choose either QSFP28 AOC or SR4 transceiver with a 12-fiber MTP cable. This depends on your reach and cost consideration.

Single-Mode Fiber Use Between Switches: >100m-2km

Reaches over 100 m but less than 2km are usually called mid-reaches. For most large data center operators, a 100GbE solution that can satisfy the mid-reach connectivity in a cost-effective way is their sweet spot. PSM4 and CWDM4/CLR4 transceivers which can respectively support up to 500 m over 12-fiber MTP single-mode fiber cable and 2 km over duplex LC single-mode fiber cable are recommended here. 

 100G QSFP28 ER4 Optical Module 

Single-Mode Fiber for Long Span: ≤10km

For very long span 100GbE deployment, such as connectivity between two buildings, mostly up to 10km, QSFP28-100G-LR4 with duplex LC single-mode fiber cable is the preferred option defined by IEEE. But now, the cost of QSFP28 LR4 is still very high.

Summary

Guanglian is certified as a National high-tech enterprise, is a leading optical transceiver solution and service provider. Guanglian's high-end optical technology platforms include COB hybrid packaging technology platform, free-space optical (FSO) design and packaging, sub-micron multi-channel optical assembly platform, semiconductor optical amplifier (SOA) platform, and silicon optical chip design and packaging. 

Our company has 3500 square meters of 10,000-class super clean workshop and facilities, the highest precision COB automatic production line, 100G high-speed optical module automation test line. Our products have been widely certificated with international standards.

For more information on using QSFP28 transceivers, welcome to contact us today or request a quote.