Optical Transceiver Modules
What is Optical Transceiver Modules/SFP?
Optical Transceiver Modules/SFP, also called fiber optic transceiver or optical transceiver, is a typically hot-pluggable device used in high-bandwidth data communications applications. Transceiver modules typically have an electrical interface on the side that connects to the inside of the system and an optical interface on the other side that connects to the various devices through a fiber optic cable. An optical module functions as a photoelectric converter which converts the electrical signal into light and vice versa. There are multiple transceiver module types available that can be used in telecommunications applications. The different specs and designs are widely used to meet the changing needs of designers.
Optical Transceiver Modules/SFP
How Many Types of Optical Modules?
GBIC was the earliest 1G module. The SFP interface was designed after the GBIC interface, and due to its smaller size, SFP is sometimes known as Mini-GBIC. SFP modules are commercially available with capability for data rates up to 100M or 1000M/1G. A variant standard, XENPAK module which is capable of 10Gbit/s is designed in 2001. However, advances in technology led to more compact form factors for 10 Gigabit Ethernet applications. Soon after 2001, two related standards emerged: XPAK and X2. Later on, vendors generally changed to use XFP modules for longer distances, and SFP+ modules for high density. As escalating demand for higher speed and bandwidth, 25GbE optics like SFP28 Modules, 40GbE optics like QSFP/QSFP+ modules, and 100GbE optics like CFP transceiver and QSFP28 modules are being widely used
- XFP (10GB Small Form-factor Pluggable) optical module: “X” is the abbreviation of Roman numerals 10, all XFP modules are 10G optical module. The XFP optical module supports LC fiber optic connectors and supports hot plugging. Compared to SFP+ and SFP optical modules, XFP optical modules are larger and longer.
- SFP (Small Form-factor Pluggable) optical module: smaller than XFP, SFP optical modules support LC fiber optic connectors, hot plugging.
- SFP+ (Small Form-factor Pluggable Plus) optical module: SFP+ refers to the increased rate of SFP module, sensitive to EMI.
- QSFP+ (Quad Small Form-factor Pluggable Plus) optical module: four-channel small hot plugging optical module. The QSFP + optical module supports MPO fiber connectors, which are larger in size than SFP + optical modules.
- CFP (Centum Form-factor Pluggable) optical module: length × width × height of CFP is defined as 144.75mm × 82mm × 13.6mm, high-speed, hot plugging and supporting for data communications and telecommunications applications.
- QSFP28 optical module: the interface package size of QSFP28 is the same with QSFP+, which is mainly used in Data Center application.
- OSFP (Octal Small Form Factor Pluggable) optical module: the OSFP is a new pluggable form factor with eight high speed electrical lanes that will initially support 400 Gbps (8x50G). It is slightly wider and deeper than the QSFP but it still supports 32 OSFP ports per 1U front panel, enabling 12.8 Tbps per 1U.
- QSFP-DD (Quad Small Form Factor Pluggable Double Density) optical module: QSFP-DD is a new module and cage/connector system similar to current QSFP, but with an additional row of contacts providing for an eight lane electrical interface. It is being developed by the QSFP-DD MSA as a key part of the industry’s effort to enable high-speed solutions.
XFP/SFP/SFP+/QSFP+/CFP/QSFP28/OSFP/QSFP-DD/-2G/4G/8G/10G/16G/25G/32G/40G/50G/100G/200G/400G/800G-BiDi/CWDM/DWDM
FAQ – Optical Transceiver Modules
What are the main types of optical transceiver modules?
The main types include SFP (1G), SFP+ (10G), SFP28 (25G), QSFP+ (40G), QSFP28 (100G), QSFP56 (200G), and QSFP-DD (400G). Each adheres to IEEE 802.3 standards for Ethernet transmission and uses standard LC or MPO interfaces per IEC 61754.
What is an optical transceiver module and how does it work?
An optical transceiver converts electrical signals into optical signals for fiber transmission and reconverts them back to electrical at the receiver end. It contains a transmitter (laser/VCSEL) and receiver (photodiode) following Telcordia GR‑468‑CORE optical reliability tests.
Which standards define optical transceiver performance?
Transceivers comply with IEEE 802.3 Ethernet protocols, ITU‑T G.957/G.695 for optical interfaces, IEC 60825‑1 for laser safety, and Telcordia GR‑468‑CORE for environmental and lifetime testing. Module housings also follow SFF or CFP/MSA specifications.
What are the typical transmission ranges of optical transceivers?
Distance depends on module type: SX up to 550 m (OM3), LX up to 10 km, EX up to 40 km, ZX up to 80 km, and DWDM transceivers > 100 km. Single‑mode versions (G.652D/G.657A1) cover long ranges under ITU‑T G.698.
What interfaces are used by optical transceivers?
Standard connectors include LC duplex for SFP and QSFP single‑mode modules, and MPO/MTP for parallel multimode (40G/100G). Optical fiber compatibility follows IEC 61754 and TIA‑568‑C.3 polarity specifications.
Which optical transceiver module should I choose?
Select the module based on data rate, distance, and connector type: for short multimode links use SFP+/QSFP+ SR (OM3/OM4); for long reach use LR or ER (OS2). Ensure conformance with IEEE 802.3 and Telcordia GR‑468 for long‑term reliability.
