Important parameters of optical module
2019-09-25
For hardware development engineers, optical modules have many important optical and electrical technical parameters, but for GBIC and SPF, only three main parameters of optical modules are needed to work smoothly.
First, central wavelength: unit nanometer (nanometer), there are three main types at present:
1) 850 nm (MM, multi-mode, low cost but short transmission distance, generally only 500 M);
2) 1310 nm (SM, single mode, high loss but low dispersion in transmission process, generally used for transmission within 40KM).
3) 1550 nm (SM, single mode, small loss but large dispersion in the transmission process, generally used for long-distance transmission over 40KM, the farthest can be without. Relay direct transmission 120KM;
Second, transmission rate: refers to the number of bits per second that transmit data, unit bps. There are currently four commonly used types: 155 Mbps, 1.25 Gbps, 2.5 Gbps, 10 Gbps, etc. The transmission rate is generally downward compatible, so 155M optical module is also called FE (100 mega) optical module, and 1.25G optical module is also called GE optical module, which is the most widely used module in optical transmission equipment. In addition, the transmission rate of SAN is 2 Gbps, 4 Gbps and 8 Gbps.
Third, transmission distance: refers to the distance that optical signal can be directly transmitted without relay amplification, unit kilometers (also known as kilometers, KM), optical mode. Blocks generally have the following specifications: multi-mode 550m, single-mode 15km, 40km, 80km and 120km, etc. See the first description for details.
In addition to the above three main technical parameters, this optical module has the following basic concepts, which need only a simple understanding:
1) Laser category: Laser is the core device of optical module, which injects current into semiconductor material and emits laser through photon oscillation and gain of resonator. At present, the most commonly used lasers are FP and DFB lasers. The difference between them is that semiconductor materials and resonator structures are different. The price of DFB lasers is much higher than that of FP lasers. FP lasers are commonly used in optical modules with transmission distance less than 40 KM, and DFB lasers are commonly used in optical modules with transmission distance greater than 40 KM.
2) Loss and Dispersion: Loss is the loss of light energy caused by absorption and scattering of medium and leakage when light travels in optical fibers. This part of energy dissipates at a certain ratio with the increase of transmission distance. Dispersion is mainly caused by the different speed of electromagnetic waves of different wavelengths propagating in the same medium, resulting in different wavelength components of optical signals arriving at the receiving end at different times due to the accumulation of transmission distance, resulting in pulse broadening, and thus the signal value can be distinguished. These two parameters mainly affect the transmission distance of optical module. In practical application, the link loss of 1310 nm optical module is generally calculated by 0.35 dBm/km. The link loss of 1550 nm optical module is generally calculated by 0.20 dBm/km. The calculation of dispersion value is very complex and is generally only for reference.
The transmitting part is that the electric signal with a certain bit rate is input and processed by the internal driver chip to drive the laser diode (LD) or light emitting diode (LED) to emit the modulated optical signal with the corresponding rate. The internal part is equipped with an automatic control circuit of optical power, so that the output power of the optical signal is stable. The receiving part is: the optical signal input module with a certain bit rate is converted to electrical signal by the light detection diode, and the corresponding bit rate electrical signal is output by the preamplifier. It includes optical receiving module, optical sending module, optical transceiver module and optical forwarding module. The main function of the optical transceiver integrated module is to realize photoelectric/electro-optical conversion, including optical power control, modulation transmission, signal detection, IV conversion and limiting amplification decision regeneration. In addition, there are anti-counterfeiting information query, TX-disable and other functions, such as SFP, SFF, SFP+, GBIC, XFP, 1x9 and so on. In addition to the photoelectric conversion function, the optical forwarding module integrates many signal processing functions, such as MUX/DEMUX, CDR, function control, performance acquisition and monitoring. Common optical forwarding modules are: 200/300 pin, XENPAK, X2/XPAK and so on. Transceiver, the English name of transceiver, is the optical module or optical module, which is an important device in optical communication system. By parameter
Pluggability: Hot and Non-Hot Pluggability
Packaging: SFP, GBIC, XFP, Xenpak, X2, 1X9, SFF, 200/3000pin, XPAK
Transmission rate: The transmission rate refers to the number of transmission bits per second, in units of Mb/s or Gb/s. Optical module products cover the following main rates: low rate, 100 Mbp, gigabit, 2.5G, 4.25G, 4.9G, 6G, 8G, 10G and 40G.
By encapsulation
1. XFP (10 Gigabit Small Form Factor Pluggable) is a heat-exchangeable, protocol-independent optical transceiver for 10Gbps Ethernet, SONET/SDH, and optical channel.
2. Small pluggable optical transceiver module (SFP) has the widest application at present.
3. BiDi series single-fiber bidirectional optical modules utilize WDM technology to achieve a bidirectional optical transmission information number (point-to-point transmission). Especially the shortage of optical fiber resources requires one optical fiber to transmit bidirectional signals. Gigac BiDi includes SFP single-fiber bidirectional (BiDi), GBIC single-fiber bidirectional (BiDi), SFP + single-fiber bidirectional (BiDi), XFP single-fiber bidirectional (BiDi), SFF single-fiber bidirectional (BiDi) and so on.
4. RJ45 small pluggable module, also known as electrical module or interface module.
5. SFF is divided into 2x5, 2x10 and so on according to its pins.
6. Gigabit Ethernet Interface Converter (GBIC) Module
7. Passive Optical Network PON (A-PON, G-PON, GE-PON) Optical Module
8.40 Gbs high-speed optical module.
9. SDH transmission module (OC3, OC12, OC48)
10. Storage modules, such as 4G, 8G, etc.
The full English name of D/T is datacom/telcom. Data communication mainly includes computer video, data communication and so on. Telcom mainly includes wireless voice communication and so on. Such products are mostly used in backbone networks of optical fiber networks. PON: English: Passive optical network is passive optical network. These products are mainly used in access network of optical fiber network system. Among them, triplex products can transmit optical fiber signals, but also output analog signals. Optical modules are mainly divided into: GBIC, SFP, SFP+, XFP, SFF, CFP and so on. Optical interface types include SC and LC. But now SFP, SFP+, XFP are commonly used, not GBIC. The reason is that GBIC is bulky and easy to break down. SFP, which is now commonly used, is small and inexpensive. Type: Single-mode optical module is suitable for long-distance transmission; multi-mode optical module is suitable for short-distance transmission.
Function: Optical module is used as carrier for transmission between switch and device, which is more efficient and safe than transceiver.
First, central wavelength: unit nanometer (nanometer), there are three main types at present:
1) 850 nm (MM, multi-mode, low cost but short transmission distance, generally only 500 M);
2) 1310 nm (SM, single mode, high loss but low dispersion in transmission process, generally used for transmission within 40KM).
3) 1550 nm (SM, single mode, small loss but large dispersion in the transmission process, generally used for long-distance transmission over 40KM, the farthest can be without. Relay direct transmission 120KM;
Second, transmission rate: refers to the number of bits per second that transmit data, unit bps. There are currently four commonly used types: 155 Mbps, 1.25 Gbps, 2.5 Gbps, 10 Gbps, etc. The transmission rate is generally downward compatible, so 155M optical module is also called FE (100 mega) optical module, and 1.25G optical module is also called GE optical module, which is the most widely used module in optical transmission equipment. In addition, the transmission rate of SAN is 2 Gbps, 4 Gbps and 8 Gbps.
Third, transmission distance: refers to the distance that optical signal can be directly transmitted without relay amplification, unit kilometers (also known as kilometers, KM), optical mode. Blocks generally have the following specifications: multi-mode 550m, single-mode 15km, 40km, 80km and 120km, etc. See the first description for details.
In addition to the above three main technical parameters, this optical module has the following basic concepts, which need only a simple understanding:
1) Laser category: Laser is the core device of optical module, which injects current into semiconductor material and emits laser through photon oscillation and gain of resonator. At present, the most commonly used lasers are FP and DFB lasers. The difference between them is that semiconductor materials and resonator structures are different. The price of DFB lasers is much higher than that of FP lasers. FP lasers are commonly used in optical modules with transmission distance less than 40 KM, and DFB lasers are commonly used in optical modules with transmission distance greater than 40 KM.
2) Loss and Dispersion: Loss is the loss of light energy caused by absorption and scattering of medium and leakage when light travels in optical fibers. This part of energy dissipates at a certain ratio with the increase of transmission distance. Dispersion is mainly caused by the different speed of electromagnetic waves of different wavelengths propagating in the same medium, resulting in different wavelength components of optical signals arriving at the receiving end at different times due to the accumulation of transmission distance, resulting in pulse broadening, and thus the signal value can be distinguished. These two parameters mainly affect the transmission distance of optical module. In practical application, the link loss of 1310 nm optical module is generally calculated by 0.35 dBm/km. The link loss of 1550 nm optical module is generally calculated by 0.20 dBm/km. The calculation of dispersion value is very complex and is generally only for reference.
The transmitting part is that the electric signal with a certain bit rate is input and processed by the internal driver chip to drive the laser diode (LD) or light emitting diode (LED) to emit the modulated optical signal with the corresponding rate. The internal part is equipped with an automatic control circuit of optical power, so that the output power of the optical signal is stable. The receiving part is: the optical signal input module with a certain bit rate is converted to electrical signal by the light detection diode, and the corresponding bit rate electrical signal is output by the preamplifier. It includes optical receiving module, optical sending module, optical transceiver module and optical forwarding module. The main function of the optical transceiver integrated module is to realize photoelectric/electro-optical conversion, including optical power control, modulation transmission, signal detection, IV conversion and limiting amplification decision regeneration. In addition, there are anti-counterfeiting information query, TX-disable and other functions, such as SFP, SFF, SFP+, GBIC, XFP, 1x9 and so on. In addition to the photoelectric conversion function, the optical forwarding module integrates many signal processing functions, such as MUX/DEMUX, CDR, function control, performance acquisition and monitoring. Common optical forwarding modules are: 200/300 pin, XENPAK, X2/XPAK and so on. Transceiver, the English name of transceiver, is the optical module or optical module, which is an important device in optical communication system. By parameter
Pluggability: Hot and Non-Hot Pluggability
Packaging: SFP, GBIC, XFP, Xenpak, X2, 1X9, SFF, 200/3000pin, XPAK
Transmission rate: The transmission rate refers to the number of transmission bits per second, in units of Mb/s or Gb/s. Optical module products cover the following main rates: low rate, 100 Mbp, gigabit, 2.5G, 4.25G, 4.9G, 6G, 8G, 10G and 40G.
By encapsulation
1. XFP (10 Gigabit Small Form Factor Pluggable) is a heat-exchangeable, protocol-independent optical transceiver for 10Gbps Ethernet, SONET/SDH, and optical channel.
2. Small pluggable optical transceiver module (SFP) has the widest application at present.
3. BiDi series single-fiber bidirectional optical modules utilize WDM technology to achieve a bidirectional optical transmission information number (point-to-point transmission). Especially the shortage of optical fiber resources requires one optical fiber to transmit bidirectional signals. Gigac BiDi includes SFP single-fiber bidirectional (BiDi), GBIC single-fiber bidirectional (BiDi), SFP + single-fiber bidirectional (BiDi), XFP single-fiber bidirectional (BiDi), SFF single-fiber bidirectional (BiDi) and so on.
4. RJ45 small pluggable module, also known as electrical module or interface module.
5. SFF is divided into 2x5, 2x10 and so on according to its pins.
6. Gigabit Ethernet Interface Converter (GBIC) Module
7. Passive Optical Network PON (A-PON, G-PON, GE-PON) Optical Module
8.40 Gbs high-speed optical module.
9. SDH transmission module (OC3, OC12, OC48)
10. Storage modules, such as 4G, 8G, etc.
The full English name of D/T is datacom/telcom. Data communication mainly includes computer video, data communication and so on. Telcom mainly includes wireless voice communication and so on. Such products are mostly used in backbone networks of optical fiber networks. PON: English: Passive optical network is passive optical network. These products are mainly used in access network of optical fiber network system. Among them, triplex products can transmit optical fiber signals, but also output analog signals. Optical modules are mainly divided into: GBIC, SFP, SFP+, XFP, SFF, CFP and so on. Optical interface types include SC and LC. But now SFP, SFP+, XFP are commonly used, not GBIC. The reason is that GBIC is bulky and easy to break down. SFP, which is now commonly used, is small and inexpensive. Type: Single-mode optical module is suitable for long-distance transmission; multi-mode optical module is suitable for short-distance transmission.
Function: Optical module is used as carrier for transmission between switch and device, which is more efficient and safe than transceiver.
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