With the popularization of 10GbE deployments, a wide range of 10G SFP+ fiber optic transceivers are designed for the delivery of 10Gbps data in various networking scenarios. Normally speaking, 10G SFP+ transceivers are twofold: copper & optical. The latter can be further divided into general modules (multimode and single mode) and modules for particular uses (SFP+ WDM modules and BiDi modules). This is a guide that will lead you to classify these 10G SFP+ available module types.
10G copper transceivers, compliant with MSA standard, are designed for the delivery of 10 Gbps data rates over Cat6a/Cat7 cable. Implemented as an SFP+ form factor, the 10G copper transceiver offers 10GbE communication over copper. Accompanied with Cat6a/Cat7 cables, the maximum transmission distance is up to 30 meters. FS has launched a new SFP+ copper transceiver that supports a link length of 80 meters on Cat6a/Cat7 cables.
Featuring with less-budget, lower-consumption, and simpler-deployment, 10G SFP+ copper transceivers are favored by many users: Firstly, copper-based infrastructure is far less expensive than fiber optics. In addition, 10GBASE-T SFP+ copper transceiver consumes 2.5w, which is less than SFP DACs that are also compliant with 10GBASE-T standard (average value: 4-8w). Understanding of 10GBASE-T SFP+ Copper Transceiver Modules will help you get more details of this SFP+ copper transceiver.
Figure 1: Direct Connection of 10G SFP+ Copper Modules
10G SFP+ Multimode Transceiver
There are two main types of 10G SFP+ multimode transceivers—10GBASE SR & 10GBASE LRM used for short-range transmission. They are all small-form factor pluggable transceivers with the function of a receiver and transmitter for the transfer of optical signals over multimode fibers.
10GBASE-SR fiber optic transceiver is one of the most commonly used modules for 10GbE. SR stands for short-range, the transmission distance of 10GBASE-SR modules can reach up to 300 meters matched with OM3 multimode fiber (MMF). The minimum cabling distance for these SR modules is 2 meters, according to the IEEE 802.3ae. Implemented with a VCSEL, 10GBASE-SR transceivers also known as the lowest-cost, lowest-power modules. The variant type is named 10GBASE-SRL (10GBASE-SR lite).
Figure 2: Direct Connection of 10G SFP+ SR Modules
As the replacement to 10GBASE-LX4 modules, 10GBASE-LRM fiber optic transceivers can support the max link lengths of 220 meters over MMF, i.e, OM3. Note, Cisco (or Cisco compatible from some vendors) 10GBASE-LRM modules can also support the max link lengths of 300 meters over single mode fiber (SMF). The minimum cabling distance for LRM modules is also 2 meters.
10G SFP+ Single Mode Transceiver
There are three main types of 10G SFP+ single mode transceivers—10GBASE-LR, 10GBASE-ER, and 10GBASE-ZR used for long-range transmission. They are all hot-swappable SFP+ modules that plug into SFP+ slots on switches.
10GBASE-LR fiber optic transceiver, LR stands for "long reach," operates at a nominal wavelength of 1310nm and can reach up to 10 km over single mode fiber with 2m minimum cabling distance. The 10GBASE-LR module is implemented with a distributed feedback laser (DFB), compared with the SR module adopting VCSEL. DFB lasers are more expensive than VCSELs, but their higher power and longer wavelength will allow efficient coupling into the small core of single mode fiber over greater distances.
Figure 3: Direct Connection of 10G SFP+ LR Modules
As an enhanced version of LR modules, the 10GBase-ER transceiver that operates at a nominal wavelength of 1550 nm is also designed for long-haul transmission over single mode fibers, which supports the link length of up to 40 kilometers. Unlike the previous modules, the 10GBASE-ER module is implemented with an externally modulated laser (EML). It's worth mentioning that the attenuator is required for links less than 20km long due to the laser power. According to the transmission distance to assure the transceiver's work, adopting the appropriate attenuators is necessary. (≤1km: 10dB; ≤10km: 7dB; ≤15km: 6dB; ≤20km: 5dB).
Similar to ER modules, the 10GBASE-ZR transceiver also operates at the nominal wavelength of 1550 nm and operates with SMFs, but with longer transmission distance—80 km. And it's also necessary to adopt the appropriate attenuator when the transmission distance is less than 80 km (≤1km: 15dB; ≤10km: 12dB; ≤15km: 11dB; ≤20km: 10dB; ≤30km: 7dB; ≤40km: 5dB; ≤50km: 2dB). 10GBase-ZR doesn't actually belong to the IEEE standard but is still provided by many vendors.
10G SFP+ WDM transceiver
Wavelength Division Multiplexing (WDM) technology can be divided into two parts: CWDM & DWDM (C=Coarse; D=Dense). 10G CWDM SFP+ transceiver often operates at 18 CWDM wavelengths from 1270nm to 1610nm, and its transmission distance is from 10 km to 80 km. While 10G DWDM SFP+ transceiver operates at DWDM wavelengths from CH17-CH61, the maximum transmission distance can up to 80 km. 10G SFP+ WDM transceivers are applied in scalable and flexible large enterprises and data center deployment.
10G SFP+ BiDi transceiver
Unlike the above mentioned traditional fiber optic transceivers, 10G SFP+ BiDi transceivers transmit and receive optical signals on separate wavelengths over one single fiber by adopting WDM technology. Thus, BiDi transceivers are also referred to as one type of WDM transceivers. And the modules must be used in pairs in order to work effectively. The link length varies from 10 km to 120 km for various requirements. On account of its maximization of the capacity and usage of optical fibers, this cost-effective solution has increasingly become the preference in many infrastructures. Understanding BiDi Transceiver will illustrate this type of 10G SFP+ module elaborately.
The endless requirements for higher bandwidth and the continuous upgrading of data centers have brought greater opportunities for the fiber optic transceiver industry. But it doesn't mean the development of the products that support relatively lower bandwidth is becoming narrower. 10G SFP+ modules are still the bias for many data centers that have servers or switches with 10G ports or have the upgrading plans through 10G relevant products. A broad range of 10G SFP+ modules is now used for 10GbE deployments in diverse networking environments and will still be the trend within a certain time.