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    Home / Products / Transceivers / 400G/800G/1.6T Ethernet Transceivers / 800G QSFP-DD / 203131

    Cisco QDD-2X400G-FR4 Compatible 800GBASE-2FR4 Twin-port QSFP-DD PAM4 1270 to 1330nm 2km DDM Dual Duplex LC/UPC SMF Optical Transceiver Module

    Product No: 203131
    48 Reviews
    280 Sold
    US$ 1,327.90
    Compatible
    Transceivers type
    18 in real-time stock, 16 Jul, 2026

    Free Shipping over US$ 79.8

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    5-Year Warranty 1-Year Exchange
    Warranty
    Providing industry-leading limited lifetime warranty.
    Please check our warranty policy for details.
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    1. 8 optical channels, dual duplex LC connectors 
2. Support 800G to 2x 400G-FR4 QSFP-DD application, no breakout cables required
3. 8x 106.25G PAM4 modulation
4. EML + PIN Laser 
5. Max power consumption ≤17W
    See more

    Specifications

    Cisco QDD-2X400G-FR4 Compatible 2x 400GBASE FR4 QSFP-DD PAM4 Optical Transceiver Module (1271nm, 1291nm, 1311nm, 1331nm, 2km, Dual Duplex LC, SMF, 0℃ to +70℃, DDM)

     

    Cisco QDD-2X400G-FR4 Compatible 2x 400G FR4 QSFP-DD 800G transceiver module supports a max data rate of 850Gbps. It enables the fiber link of 2km over single-mode fiber (SMF) with dual duplex LC connectors. The 800 Gigabit Ethernet signal is carried over 4 wavelengths at 1271nm, 1291nm, 1311nm, and 1331nm. QSFPTEK manufactured  2x 400GBASE FR4 QSFP-DD complies with IEEE 802.3cu-2021, IEEE P802.3ck D3.0, QSFP-DD MSA HW Rev 6.01, CMIS Rev 5.0. DDM (digital diagnostics monitoring) function is supported on the 800G fiber optic transceiver to achieve real-time operating parameters monitoring. Adopting the Pulse-amplitude Modulation (PAM4) modulation, the FR4 QSFP-DD achieves 800 Gigabit Ethernet through 8x 106.25 PAM4 Retimed 2x400GAUI-4 C2M electrical interface. The 800G FR4 QSFP-DD is widely used for gigabit Ethernet, data centers, and 800G to 2x 400G applications.

     

    Part Number QT-QSFP-DD-800G-2FR4-LC Vendor Name QSFPTEK
    Form Factor QSFP-DD Max Data Rate 850 Gbps (8x 106.25 Gbps)
    Wavelength 1271nm, 1291nm, 1311nm and 1331nm Distance 2km
    Connector Dual LC Duplex Cable Type SMF
    Transmitter Type EML Receiver Type PIN
    TX Power -3.2 to +4.4dBm Receiver Sensitivity -7.2dBm
    Power Consumption ≤17W Modulation Format PAM4
    DDM/DOM Supported Temperature 0 to 70°C (32 to 158°F)
    Protocols IEEE 802.3cu-2021, IEEE P802.3ck D3.0, QSFP-DD800 MSA HW Rev 6.01, CMIS Rev 5.0 Warranty 1 Year
    Quality Testing Program
    Optical Transceivers Testing

    Take a look at our test program to get the reliable and high-performance optical transceivers.

    Quality Certifications

    Applications

    Scenario 1: 800G to 800G Direct Connectivity

     

    QT-QSFP-DD-800G-2FR4 Scenario 1 800G to 800G Direct Connectivity 

      

    Scenario 2: 800G to 2x 400GE Connectivity

      

    QT-QSFP-DD-800G-2FR4 Scenario 2 800G to 2x 400GE Breakout Connectivity

     

    Product details

    8x 100Gbps PAM4 Modulation Technology

       

    Utilize 8x electrial lanes and 8x optical lanes modulated at 100G PAM-4 per lane. On the output side, it convert 8x 106.25Gb/s electrical signal to 8x 106.25Gb/s optical signals. On the receiver side, it convert 8x 100Gb/s optical signal to 8x 100Gb/s electrical signals.

     

      

       

    Easy 800G to 2x 400G breakout with OS2 SMFs

       

    The QSFP-DD-800G-2FR4 module is designed with dual duplex LC connectors, while each connector can connect to a physically separate 400G FR4 module via an LC OS2 duplex single-mode fiber. This enables 800G to 2x 400G breakout links without the need for using breakout fiber optic cables. 

     QSFP-DD 2FR4 BREAKOUT

          

     

    Various Switch Tests

     

    Every module is quality tested for compatibility in the multi-brand switches environment, which guarantees flawless operations.

     

    QSPFTEK LAB All Brands Switches Show

     

     

    Tested in The Host Device to Prove Interoperability

     

    Every unit sold undergoes rigorous quality testing, to ensure compatibility in the target switch environment, guaranteeing perfect operation.

     

    QSFPTEK Test Rack

     

     

    Comprehensive Testing

     

    Every module is qualified through rigorous procedures and advanced equipment to ensure high-quality and reliable optical devices for you.

     

    QSFPTEK Test Devices

      

     

    800G QSFP-DD Optical Transceivers Contrast Table

     

    Part Number

    QT-QSFP-DD-800G-SR8

    QT-QSFP-DD-800G-2VR4

    QT-QSFP-DD-800G-DR8

    QT-QSFP-DD-800G-2DR4

    Image

    Data Rate

    800G

    800G

    800G

    800G

    Optical Connector

    Single MPO-16/APC

    Dual MPO-12/APC

    Single MPO-16/APC

    Dual MPO-12/APC

    Cable Type

    MMF

    MMF

    SMF

    SMF

    Wavelength

    850nm

    850nm

    1310nm

    1310nm

    Reach

    50m

    50m

    500m

    500m

    Modulation

    PAM4

    PAM4

    PAM4

    PAM4

    Max Power Consumption

    < 16W

    < 16W

    < 16.5W

    < 18W

    Application

    800G to 800G, 800G to 2x400G breakout

    800G to 800G, 800G to 2x400G breakout

    800G to 800G, 800G to 2x400G breakout, 800G to 8x100G breakout

    800G to 800G, 800G to 2x400G breakout

    Matching Downlink  Transceivers

    QT-QSFP-DD-SR4 (400G)

    QT-Q112-400G-SR4

    QT-OSFP-400G-SR4

    QT-QSFP-DD-SR4 (400G)

    QT-Q112-400G-SR4

    QT-OSFP-400G-SR4

    QT-QSFP-DD-DR4 (400G)

    QT-Q112-400G-DR4

    QT-OSFP-400G-DR4

    QT-QSFP28-DR1

    QT-QSFP-DD-DR4 (400G)

    QT-Q112-400G-DR4

    QT-OSFP-400G-DR4

    Part Number

    QT-QSFP-DD-800G-2XDR4

    QT-QSFP-DD-800G-2FR4

    QT-QSFP-DD-800G-2LR4

    		  

    Image

    		 

    Data Rate

    800G

    800G

    800G

    		  

    Optical Connector

    Dual MPO-12/APC

    Dual Duplex CS/UPC

    Dual Duplex LC/UPC

    		  

    Cable Type

    SMF

    SMF

    SMF

    		  

    Wavelength

    1310nm

    1271nm, 1291nm, 1311nm and 1331nm

    1271nm, 1291nm, 1311nm and 1331nm

    		  

    Reach

    2km

    2km

    10km

    		  

    Modulation

    PAM4

    PAM4

    PAM4

    		  

    Max Power Consumption

    < 18W

    < 18W

    ≤ 18W

    		  

    Matching Transceivers

    QT-QSFP-DD-DR4+ (400G)

    QT-Q112-400G-DR4+

    QT-QSFP28-FR1

    QT-QSFP-DD-FR4 (400G)

    QT-Q112-400G-FR4

    QT-OSFP-400G-FR4

    QT-QSFP-DD-LR4 (400G)
    QT-OSFP-400G-LR4

    		  

    Application

    800G to 800G, 800G to 2x400G breakout, 800G to 8x100G breakout

    800G to 800G, 800G to 2x400G breakout

    800G to 800G, 800G to 2x400G breakout

    		  

    Questions & Answers

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    • ALL (14)
    • Excellent Quality (2)
    • Shopping Experience (4)
    • Easy to Use (1)
    • High Reliability (2)
    • DDM (1)
    • High Performance (4)
    • Good Price (1)
    • Fast Delivery (1)
    • Compatibility (2)
    • Edwina House United States of America
      2026-07-06

      Reliable module with clear labeling and smooth installation. I'd purchase this model again for future expansion projects.

      Transceivers typeQDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

      CompatibleCisco

      Verified Purchase

      Helpful

      0

    • Tabitha Harrison United States of America
      2026-07-03

      Great value for an 800G optical module, and the entire purchasing process was hassle-free.

      Transceivers typeQDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

      CompatibleCisco

      Verified Purchase

      Helpful

      0

    • Crystal Dierser United States of America
      2026-06-29

      This was our first time ordering from this supplier, and the overall experience was smooth. The product matched the description exactly, arrived in excellent condition, and was ready to use right away. I'd feel confident placing another order for future expansion.

      Transceivers typeQDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

      CompatibleCisco

      Verified Purchase

      Helpful

      0

    • Raymond Anne United States of America
      2026-06-26

      Tested optics from several suppliers over the past year, and this module compared very well. The coding worked correctly with our existing switches, so deployment was quick and uneventful. Considering both compatibility and price, this has been one of the better purchases for our recent upgrade.

      Transceivers typeQDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

      CompatibleCisco

      Verified Purchase

      Helpful

      0

    • Gerald United States of America
      2026-06-24

      The modules were recognized immediately by our equipment. Installation took minutes, and we were up and running without any troubleshooting.

      Transceivers typeQDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

      CompatibleCisco

      Verified Purchase

      Helpful

      0

    • Suzanne Rayleign China
      2026-06-18

      Used several of these modules in a production environment. The labeling was clear, the packaging was neat, and the modules looked professionally manufactured. After installation, link stability was excellent and optical readings remained consistent. Very satisfied with the overall quality.

      Transceivers typeQDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

      CompatibleCisco

      Verified Purchase

      Helpful

      0

    • Atlas Jackson United States of America
      2026-06-11

      Been pushing traffic for a couple weeks now, zero drops. QSFPTEK keeps delivering solid stuff at half the price of Cisco-branded. Definitely grabbing more for the next rack.

      Transceivers typeQDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

      CompatibleCisco

      Verified Purchase

      Helpful

      0

    • Dean United States of America
      2026-06-09

      We use these in a lab environment with frequent hardware changes. They've held up well through repeated installs and removals.

      Transceivers typeQDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

      CompatibleCisco

      Verified Purchase

      Helpful

      0

    • Noah United Kingdom
      2026-05-31

      The entire purchasing experience was smooth, from product consultation to delivery. The technical team provided professional recommendations and helped us choose the right modules for our application. Installation was simple and hassle-free.

      Transceivers typeQDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

      CompatibleCisco

      Verified Purchase

      Helpful

      0

    • Ismail Malaysia
      2026-05-12

      We got this 800G twin-port module for our data center upgrade, lah. Plug into our Cisco gear, straight away can work, no compatibility issue what. Already running solid for weeks. QSFPTEK memang deliver, for sure we'll buy more from them.

      Transceivers typeQDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

      CompatibleCisco

      Verified Purchase

      Helpful

      0

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    Resources

    • PDF Document
      QT-QSFP-DD-800G-2FR4 LC Datasheet.pdf
    • PDF Document
      Transceiver Module User Guide.pdf
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    Cisco QDD-2X400G-FR4 Compatible 800GBASE-2FR4 Twin-port QSFP-DD PAM4 1270 to 1330nm 2km DDM Dual Duplex LC/UPC SMF Optical Transceiver Module

    Compatible Cisco

    Transceivers type QDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

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    Mark

    2023-12-15
    This product works well with my switch, and I plan to buy some DWDM transceivers from QT. Excellent value fo ct works well with my switch, and I plan to buy some DWDM transceivers from QT. Excellent valur money!

    Verified Purchase

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    Cisco QDD-2X400G-FR4 Compatible 800GBASE-2FR4 Twin-port QSFP-DD PAM4 1270 to 1330nm 2km DDM Dual Duplex LC/UPC SMF Optical Transceiver Module
    US$ 1,327.90
    Compatible
    Cisco
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    QDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC
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    Cisco QDD-2X400G-FR4 Compatible 800GBASE-2FR4 Twin-port QSFP-DD PAM4 1270 to 1330nm 2km DDM Dual Duplex LC/UPC SMF Optical Transceiver Module

    Compatible Cisco

    Transceivers type QDD-2X400G-FR4 | 2km | Dual Duplex LC/UPC

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