Cisco QSFP-40G-SR-BD= · 40G BiDi QSFP+ Transceiver for Duplex Multimode Fibre
40 Gbps on 2 fibresDuplex LC · multimodeOM4 up to 150 mGenuine Cisco spare (=)
The Cisco QSFP-40G-SR-BD= is a genuine Cisco 40G QSFP+ BiDi transceiver that carries 40 Gbps over a single duplex multimode fibre pair with LC connectors, reaching 100 m on OM3 and 150 m on OM4/OM5, so data centres can move from 10G to 40G without re-cabling to 8-fibre MPO trunks.
Instead of the four fibre pairs used by 40GBASE-SR4, the BiDi module sends two 20 Gbps channels in opposite directions on each fibre, using two wavelengths in the 832–918 nm band (about 850 and 900 nm). It draws 3.5 W, uses a class 1M laser and is designed for the QSFP MSA, so it fits Cisco 40G QSFP+ ports across switches and routers.
Before you order: BiDi only talks to BiDi: the far end must also be a 40G QSFP+ BiDi module. It does not interoperate with 40GBASE-SR4 (MPO) optics. Operating temperature is +10 to 70 °C, narrower than standard commercial optics.
What's in the Box
- 1 × Cisco QSFP-40G-SR-BD= QSFP+ BiDi transceiver (with dust plug)
- Fibre patch cords are not included — order multimode LC-LC duplex cords (OM3/OM4) separately
What It Means in Practice
- Upgrade existing 10G duplex LC multimode links to 40G by swapping the optics only.
- Saves fibre: 2 strands per 40G link instead of 8 with SR4.
- Typical use: leaf-spine or top-of-rack uplinks within the same hall up to 150 m on OM4.
- Genuine Cisco optic for platforms where TAC support depends on Cisco-branded transceivers.
What Will Not Work
- 40GBASE-SR4 or other non-BiDi 40G optics at the far end.
- Single-mode fibre — use an LR4 module instead.
- QSFP-40G-BD-RX (receive-only tap module) as a normal link partner.
- APC patch cords or 10G SFP+ ports.
Key Features
40G on duplex fibre
Two 20 Gbps wavelengths per direction over one LC pair.
Re-use 10G cabling
No need for MPO trunks when moving from 10G to 40G.
Up to 150 m
OM3 100 m, OM4/OM5 150 m, OM2 30 m.
Genuine Cisco
Native support in Cisco IOS/NX-OS platforms.
Technical Specifications
| Identification |
| Part Number |
QSFP-40G-SR-BD= |
| EAN / GTIN |
0882658634543 |
| Brand |
Cisco |
| Type |
40GBASE-SR BiDi |
| Optical |
| Channels |
2 × 20 Gbps, 832–918 nm band |
| Fibre type |
Multimode, duplex |
| Reach |
OM2 30 m · OM3 100 m · OM4/OM5 150 m |
| Connector |
Duplex LC (PC/UPC) |
| Transmit power per lane |
−4 to +5 dBm |
| Receive power per lane |
−6 to +5 dBm |
| Laser class |
1M |
| Electrical & environment |
| Form factor |
QSFP+ (QSFP MSA) |
| Power consumption |
3.5 W |
| Operating temperature |
+10 to 70 °C |
| Storage temperature |
−40 to 85 °C |
| Warranty |
| Warranty |
1-Year Warranty (Singular) |
| Manufacturer Term |
Cisco standard warranty 5 years per Cisco data sheet — claims handled through Singular |
Frequently Asked Questions
Can I connect it to a 40G-SR4 module?
No. BiDi uses two wavelengths on one fibre pair, SR4 uses eight fibres on MPO — both ends must be BiDi.
Will my existing 10G fibre work?
Usually yes if it is OM3/OM4 duplex LC within 100/150 m. Old OM2 is limited to 30 m.
Does it fit my Cisco switch?
It fits Cisco 40G QSFP+ ports. Send us the switch model and software version and we check the Cisco compatibility matrix.
Singular Expert Insight · Buyer's Guide
QSFP-40G-SR-BD is the cheapest path from 10G to 40G when your multimode duplex cabling is already in place — no new trunks. Just order BiDi for both ends. See our
switches with 40G QSFP+ ports.
✓ Buy it if you want 40G over existing duplex OM3/OM4 fibre between Cisco switches.
✕ Skip it if the far end uses SR4/MPO, your fibre is single-mode, or the link is longer than 150 m.
→ Also consider 40GBASE-SR4 MPO optics if you already have 8-fibre MPO trunks.
Not sure it fits your setup? Send us the model of your rack, switch or device and we will check compatibility before you order.