Encyclopedia of Megabyte optical modules
Megabyte optical module is a photoelectric conversion device with a transmission rate of 155Mb/s, which is used for Ethernet network or SDH/SONET. It is generally only used for 100M SFP package interface. The optional wavelength is 1310nm and 1550nm.
Concept
The 100 megabit SFP optical module is a small pluggable (SFP) transceiver module based on the SFP multi-source protocol (MSA), which can provide a complete two-way data link connection for data communication and realize the high-speed and transparent transmission of data information by cooperating with the optical fiber. It is an SFP optical module connected to a copper wire network that supports the 100base-t Ethernet standard. It is mainly used for FAST Ethernet FAST Ethernet and is compatible with the 100mb Ethernet and 100base-t Ethernet standards specified in IEEE 802.3z and 802.3ab.
Principle
The 100 Megabyte optical module is composed of several parts, such as optoelectronic device, functional circuit and optical interface, and optoelectronic device is composed of transmitting and receiving parts.
The transmitting part is: the electrical signal with a certain bit rate is processed by the internal drive chip to drive the semiconductor laser (LD) or LED (LED) to emit the modulated optical signal of the corresponding rate, and its internal optical power automatic control circuit, so that the output optical signal power remains stable.
The receiving part is: the optical signal input module with a certain bit rate is converted into an electrical signal by an optical detection diode. After the preamplifier outputs the corresponding bit rate electrical signal, the output signal is generally PECL level. At the same time, an alarm signal will be output after the input light power is less than a certain value.
Feature
1. Double/single LC optical interface
2, hot plug, in line with the requirements of SFP MSA and sff-8472
3. 1310nm FP LD or 1310 DFB LD or 1550 DFB LD
4. PIN PD receiving or APD PD receiving
5. + 3.3v single power supply
6. Metal packaging, good EMI and EMC performance
7. Working rate: oc-3 / stm-1, oc-12 / stm-4, oc-24 /Gigabit Ethernet, OC48/ stm-16
8. The reliability meets Bell core 468
9. ISO9001 quality system
10, the transmission distance: 2 km, 15 km, 40 km, 80 km, 100 km, 120 km
Important parameters
1. Central wavelength: unit of nanometer (nm), currently there are three main types:
850nm (MM, multi-mode, low cost but short transmission distance, generally can only transmit 500M);
1310nm (SM, single mode, large loss but small dispersion during transmission, generally used for transmission within 40KM);
1550nm (SM, single mode, low loss but large dispersion in the transmission process, generally used for long-distance transmission over 40KM, up to 120KM direct transmission without relay);
2. Transmission distance: refers to the distance that the optical signal can be transmitted directly without the need of relay amplification, in kilometers (also known as kilometers, km).
Optical modules generally have the following specifications: multimode 550m, single-mode 15km, 40km, 80km and 120km, etc.
3. Category of lasers: lasers are the most core devices in the optical module, which inject current into the semiconductor material and emit laser light through the photon oscillation and gain of the resonator cavity.
FP laser is generally used in optical modules with transmission distance of less than 40KM
DFB laser is generally used in optical modules with transmission range ≥40KM
4. Loss and dispersion: loss refers to the loss of light energy due to the absorption scattering and leakage of the medium during the transmission of light in the optical fiber. This part of energy dissipates at a certain rate with the increase of transmission distance.
The 1310nm optical module generally calculates the link loss at 0.35dBm/km
The link loss of the 1550nm optical module is generally calculated at 0.20dBm/km
The calculation of dispersion value is very complex and is generally only used for reference
5. optical fiber interface:
100 trillion SFP optical modules are LC interface
6. Service life of the optical module:
International standard, 7 Х 24-hour work 50000 hours (equivalent to 5 years)
Application
The 100 MB SFP optical module is widely used and supports many SFP type interface devices, including Ethernet, switches, routers, and other network devices. The 100 megabit SFP optical module supports 100Mbps data transmission rate and 100m link length, and realizes miniaturized network interface card (NIC) and uplink. As a result, it is ideal for high-density LAN 100 base-t fiber channels, gigabit Ethernet, and LAN switches to connect switches to switch interfaces, switch to switch SerDes interfaces, switch to switch SGMII interfaces, switch backboards, gaming devices, router/server interfaces, and other optical transmission systems.
Failure reason
The optical module's light port is exposed to the environment, and the light port is polluted by dust. The end face of the optical connector used has been polluted, and the optical port of the optical module has been polluted twice. Pigtailed optical connector end use undeserved, end surface scratches, etc. Use bad fiber optic connectors.
