Share common knowledge of optical fibers, optical modules and optical interfaces
2023-01-04
This article shares the common sense of optical fibers, optical modules and optical interfaces for you, and hopes to help everyone.
Optical modules commonly used in Ethernet switches are SFP, GBIC, XFP and XENPAK.
Their full names in English:
SFP: Small Form Factor Pluggable Transceiver, Small Form Factor Pluggable Transceiver
GBIC: Gigabit Interface Converter, Gigabit Ethernet Interface Converter
XFP: 10 Gb small form-factor pluggable transceiver 10 Gb Ethernet interface
Pluggable transceivers in small packages
XENPAK: 10 Gigabit Ethernet Transceiver PAcKage 10 Gigabit Ethernet Interface Transceiver Capture Packet
Fiber optic connectors
Fiber optic connectors consist of optical fibers and plugs at both ends of the optical fiber. The plug consists of a pin and a perimeter locking structure. According to different locking mechanisms, optical fiber connectors can be divided into FC type, SC type, LC type, ST type and KTRJ type.
FC connectors adopt a threaded locking mechanism and are fiber optic removable connectors.
SC is a rectangular joint developed by NTT. Direct insertion and removal without threaded connections. Compared to FC connectors, it has a small operating space and is easy to use. Low-end Ethernet products are very common.
LC is a Mini-type SC connector developed by LUCENT. It has a smaller size and is already widely used in the system. This is the direction of the future development of optical fiber connectors. Low-end Ethernet products are very common.
ST connectors were developed by AT&T. It uses a bayonet locking mechanism. The main parameters are equivalent to FC and SC connectors, but are not common in companies. They are commonly used in multimode devices to connect with other manufacturers. Use more when docking.
KTRJ's dowels are made of plastic and positioned by steel dowels. As the number of inserts and removals increases, the mating surface wears out gradually and is not as stable as ceramic pin connectors in the long term.
Fiber knowledge
Optical fibers are conductors that transmit light waves. From the perspective of optical transmission, optical fiber can be divided into single-mode fiber and multimode fiber.
In single-mode fiber, there is only one basic mode of optical transmission, which means that light travels only along the inner core of the fiber. Since mode dispersion is completely avoided, single-mode fiber has a wide transmission frequency band and is suitable for high-speed, long-distance fiber optic communication.
In multimode fiber, there are multiple modes of optical transmission. Due to dispersion or aberrations, such optical fibers have poor transmission performance, narrow frequency bands, small transmission rates and short distances.
Fiber characteristics
The structure of the fiber is prefabricated from quartz fiber rods, and the outer diameter of both multimode and singlemode fiber for communication is 125 μm.
The slimming is divided into two areas: the core and the cladding. Single-mode fiber cores have a core diameter of 8 to 10 μm. Multimode fiber core diameters are available in two standard sizes, 62.5μm (US standard) and 50μm (European standard).
The interface fiber specification is described as follows: 62.5μm/125μm multimode fiber, where 62.5μm refers to the core diameter of the fiber and 125μm refers to the outer diameter of the fiber.
Single-mode fiber uses wavelengths of 1310 nm or 1550 nm.
Multimode fiber uses a wavelength of 850 nm.
Optical modules commonly used in Ethernet switches are SFP, GBIC, XFP and XENPAK.
Their full names in English:
SFP: Small Form Factor Pluggable Transceiver, Small Form Factor Pluggable Transceiver
GBIC: Gigabit Interface Converter, Gigabit Ethernet Interface Converter
XFP: 10 Gb small form-factor pluggable transceiver 10 Gb Ethernet interface
Pluggable transceivers in small packages
XENPAK: 10 Gigabit Ethernet Transceiver PAcKage 10 Gigabit Ethernet Interface Transceiver Capture Packet
Fiber optic connectors
Fiber optic connectors consist of optical fibers and plugs at both ends of the optical fiber. The plug consists of a pin and a perimeter locking structure. According to different locking mechanisms, optical fiber connectors can be divided into FC type, SC type, LC type, ST type and KTRJ type.
FC connectors adopt a threaded locking mechanism and are fiber optic removable connectors.
SC is a rectangular joint developed by NTT. Direct insertion and removal without threaded connections. Compared to FC connectors, it has a small operating space and is easy to use. Low-end Ethernet products are very common.
LC is a Mini-type SC connector developed by LUCENT. It has a smaller size and is already widely used in the system. This is the direction of the future development of optical fiber connectors. Low-end Ethernet products are very common.
ST connectors were developed by AT&T. It uses a bayonet locking mechanism. The main parameters are equivalent to FC and SC connectors, but are not common in companies. They are commonly used in multimode devices to connect with other manufacturers. Use more when docking.
KTRJ's dowels are made of plastic and positioned by steel dowels. As the number of inserts and removals increases, the mating surface wears out gradually and is not as stable as ceramic pin connectors in the long term.
Fiber knowledge
Optical fibers are conductors that transmit light waves. From the perspective of optical transmission, optical fiber can be divided into single-mode fiber and multimode fiber.
In single-mode fiber, there is only one basic mode of optical transmission, which means that light travels only along the inner core of the fiber. Since mode dispersion is completely avoided, single-mode fiber has a wide transmission frequency band and is suitable for high-speed, long-distance fiber optic communication.
In multimode fiber, there are multiple modes of optical transmission. Due to dispersion or aberrations, such optical fibers have poor transmission performance, narrow frequency bands, small transmission rates and short distances.
Fiber characteristics
The structure of the fiber is prefabricated from quartz fiber rods, and the outer diameter of both multimode and singlemode fiber for communication is 125 μm.
The slimming is divided into two areas: the core and the cladding. Single-mode fiber cores have a core diameter of 8 to 10 μm. Multimode fiber core diameters are available in two standard sizes, 62.5μm (US standard) and 50μm (European standard).
The interface fiber specification is described as follows: 62.5μm/125μm multimode fiber, where 62.5μm refers to the core diameter of the fiber and 125μm refers to the outer diameter of the fiber.
Single-mode fiber uses wavelengths of 1310 nm or 1550 nm.
Multimode fiber uses a wavelength of 850 nm.
