Types of Optical Modules
Optical modules are available in various types to meet diversified requirements.
Classified by transmission rates
Depending on transmission rates, optical modules are classified into FE, GE, 10GE, and 40GE optical modules.
Classified by encapsulation types
The higher transmission rate an optical module provides, the more complex structure it has. Optical modules are encapsulated in different modes to provide different structures. Huawei routers support optical modules of the following encapsulation types: SFP, eSFP, SFP+, XFP, and QSFP+.
- SFP: small form-factor pluggable. SFP optical modules support LC fiber connectors and are hot swappable.
- eSFP: enhanced small form-factor pluggable. An eSFP module is an SFP module that supports monitoring of voltage, temperature, bias current, transmit optical power, and receive optical power. Sometimes, eSFP is also called SFP.
- SFP+: small form-factor pluggable plus, SFP with a higher rate. SFP+ optical modules are more sensitive to electromagnetic interference (EMI) because they have a higher rate. To reduce EMI, SFP+ optical modules have more springs than SFP optical modules and the cages for SFP+ modules on a card are tighter.
- XFP: 10 Gigabit small form-factor pluggable. X is the Roman numeral 10, meaning that all XFP optical modules provide a 10 Gbit/s transmission rate. XFP optical modules support LC fiber connectors and are hot swappable. They are wider and longer than SFP+ optical modules.
- QSFP+: quad small form-factor pluggable. QSFP+ optical modules support MPO fiber connectors and are larger than SFP+ optical modules.
Classified by physical layer standards
Different physical layer standards are defined to allow data transmission in different modes. Therefore, different types of optical modules are produced to comply with these standards. The Standard column of Table 9-1 lists the physical layer standards.
Classified by modes
Optical fibers are classified into single-mode and multimode fibers. Therefore, optical modules are also classified into single-mode and multimode modules to support different optical fibers.
Single-mode optical modules are used with single-mode fibers. Single-mode fibers support a wide band and large transmission capacity, and are used for long-distance transmission.
Multimode optical modules are used with multimode fibers. Multimode fibers have lower transmission performance than single-mode fibers because of modal dispersion, but their costs are also lower. They are used for small-capacity, short-distance transmission.
Table 9-1 provides optical module classification based on different factors.
Encapsulation Type |
Rate |
Standard |
Description |
|---|---|---|---|
SFP |
FE |
100BASE-FX (IEEE 802.3u) |
Uses one Rx multimode fiber and one Tx multimode fiber to transmit data at 100 Mbit/s over a distance within 2 km. |
GE |
1000BASE-BX (IEEE 802.3ah) |
Uses one single-mode fiber for bidirectional transmission at 1 Gbit/s over a distance within 10 km. |
|
eSFP |
FE |
100BASE-LX (IEEE 802.3ah) |
Uses one Rx single-mode fiber and one Tx single-mode fiber to transmit data at 100 Mbit/s over a distance within 80 km. |
100BASE-BX (IEEE 802.3ah) |
Uses one single-mode fiber for bidirectional transmission at 100 Mbit/s over a distance within 15 km. |
||
GE |
1000BASE-SX (IEEE 802.3z) |
Uses one single-mode fiber for bidirectional transmission at 1 Gbit/s over a distance within 1 km. |
|
1000BASE-LX (IEEE 802.3z) 1000BASE-LX10 (IEEE 802.3ah) |
Uses one Rx single-mode fiber and one Tx single-mode fiber to transmit data at 1 Gbit/s over a distance within 40 km. |
||
1000BASE-EX |
Uses one Rx single-mode fiber and one Tx single-mode fiber to transmit data at 1 Gbit/s over a distance within 40 km. |
||
1000BASE-ZX |
Uses one Rx single-mode fiber and one Tx single-mode fiber to transmit data at 1 Gbit/s over a distance within 100 km. |
||
1000BASE-BX |
Uses one single-mode fiber for bidirectional transmission at 1 Gbit/s over a distance within 40 km. |
||
CWDM |
Coarse wavelength division multiplexing, which uses one single-mode fiber to transmit signals on multiple channels. It transmits data at 1 Gbit/s over a distance within 80 km. |
||
DWDM |
Dense wavelength division multiplexing, which uses one single-mode fiber to transmit signals on multiple channels. It transmits data at 1 Gbit/s over a distance within 120 km. |
||
SFP+ |
10GE |
10GBASE-USR |
Uses one Rx multimode fiber and one Tx multimode fiber to transmit data at 10 Gbit/s over a distance within 100 m. |
10GBASE-BX |
Uses one single-mode fiber for bidirectional transmission at 10 Gbit/s over a distance within 10 km. |
||
|
10GE |
10GBASE-SR (IEEE 802.3ae) |
Uses one Rx multimode fiber and one Tx multimode fiber to transmit data at 10 Gbit/s over a distance within 400 m. |
10GBASE-LR (IEEE 802.3ae) |
Uses one Rx single-mode fiber and one Tx single-mode fiber to transmit data at 10 Gbit/s over a distance within 10 km. |
||
10GBASE-ER (IEEE 802.3ae) |
Uses one Rx single-mode fiber and one Tx single-mode fiber to transmit data at 10 Gbit/s over a distance within 40 km. |
||
10GBASE-ZR |
Uses one Rx single-mode fiber and one Tx single-mode fiber to transmit data at 10 Gbit/s over a distance within 80 km. |
||
QSFP+ |
40GE |
40GBASE-SR4 (IEEE 802.3ba) |
Uses one Rx multimode fiber and one Tx multimode fiber to transmit data at 40 Gbit/s over a distance within 400 m. |
40GBASE-LR4 (IEEE 802.3ba) |
Uses one Rx single-mode fiber and one Tx single-mode fiber to transmit data at 40 Gbit/s over a distance within 10 km. |