On average, single-mode transceivers continue to cost from 1.5 to 4 - 5 times more than multimode transceivers, depending on the data rate. When choosing between these two fiber . 2. Reference#: 69161. A micron is a unit of measure equal to 1 millionth of a meter. It is also about 2 to 4 times costlier compare to multimode version. 94, no. It supports a link length of 10 kilometers on standard Single-Mode Fiber (SMF, G.652). The diameter of a single mode core is 9µm. 10km. Single mode SFP (SMF SFP) work mainly in 1310nm and 1550nm . OS2 fiber can transport data at 100G for up to 10km using a 1310nm transceiver, or up to 40km using a 1550nm transceiver. Transmission rate of single mode fiber is higher than the multimode fiber. This is useful when you already have fibre cabling installed and additional performance is required. Single-mode fiber allows only one mode of light to propagate through the fiber, whereas multimode fiber allows multiple modes of light to propagate through the fiber. However, the optics are twice the cost of MMF optics. Single-mode fibers provide a single pathway for light to travel and are defined by their small core size of approximately 8.3 µm. Both fiber types have a cladding diameter of 125 . Single mode fiber has a much longer maximum distance than multimode fiber. The components used in single-mode optical modules are twice that of multi-mode optical modules, so the overall cost of single-mode . The single mode's smaller core size means it has lower attenuation and transmits at higher bandwidths and over longer distances. Both fiber types have a cladding diameter of 125 . Multi-mode fiber (MMF) have 4 different grades: 1. Single-mode fibre (also referred to as fundamental or mono-mode fibre) will permit only one mode to propagate and, as such, cannot suffer mode delay differences. May 12th, 2016 at 2:26 PM. Single Mode Fiber Distance and Bandwidth. Multimode vs. Single-Mode Fiber Distance. All OS2 Single-mode fiber cables feature premium 3mm fiber and a core . OS2 fiber is a loose tube cable . 94, no. When choosing between these two fiber . However, compared to single-mode fibers, the multi-mode fiber bandwidth-distance product limit is lower. Item#: COR-144EUF-T4101D20. And The minimum distance between two connected stations is 6.56 feet (2 meters). On the other hand, single-mode fiber has 8-12 μm and 125 μm respective core and cladding diameter. The diameter of a single mode core is 9µm. Single mode fiber is more efficient to manufacture, leading to an average of 30% . 100G OS2 Single-Mode Fiber Cables are the highest performing fiber optic cables currently available, with further distances than multimode specifications. 1310nm. The smaller size is what allows these cables to transmit data across a distance of up to 40 miles with a bandwidth of 1Gbs . Click here to shop our range of fibre optic cables. Using these dual-rated cables saves you the time and hassle of making . Fiber Distance. Single-mode fiber is a type of optical fiber that transmits only one wavelength of light at a time. While multimode fiber generally can go as far as 2km. There are some advantages on Single mode. Single mode fiber also accommodates much higher bandwidths than multimode. Note, however, that connector color codes vary. Applications utilizing single mode will typically encounter less data loss and interference. 3. UTILITY. When working with distances up to 2 km, use multimode optical-fiber cable. However, the light source for single-mode fiber is a laser of 1550nm wavelength while the multimode fiber runs on multiple sources of LED bulbs of more than 850nm wavelength. Single mode fiber covers distance greater than 10miles. Single-mode fiber features only one transmission mode. Single-mode fibers provide a single pathway for light to travel and are defined by their small core size of approximately 8.3 µm. Distance Limitations of Single Mode FIber. more expensive than VCSELs but their high power and longer wavelength allow efficient coupling into the small core of single-mode fiber over greater distances. Single mode fiber supports short distance transmission and long distance transmission regardless of signal bandwidth and/or resolution (such as 1080p, 4K and 8K video). So the single-mode module works mainly in the 1310nm and 1550nm wavelengths and is mostly used in a long distances transmission environment reaching 2 km, 10 km, 40 km, 60 km, 80 km and 120 km. This means there's no interference or overlap between the different wavelengths of light to garble your data over long distances like there is with multimode cable. A single mode fiber cable has an optical core that is 9µm, while modern multimode cables use 50µm. As you can see from the chart below, different Fiber core types have vastly different limitations for speed and maximum distance. In singlemode fiber, all light from a pulse travels at about the same speed and arrives at roughly the same time, eliminating the effects of modal dispersion found in multimode fiber. By using singlemode Transceivers and a Mode Conditioning cable, you can increase the range on OM1 fibre optic cable to 550m at Gigabit, and OM1/OM2 to 300m at 10Gigabit. Single mode fiber can go as far as 10km, 40km, 80km, and even farther. The only text on it says Owens Corning and the cable length numbers. 10 Helpful. Some studies report a difference of 100,000 GHz. From the chart, we can see that single mode fiber distance is much longer than that of multimode fiber cables at the data rate from 1G to 10G, but OM3/OM4/OM5 multimode fiber supports a higher data rate. Also, what speed can be expected at the maximum distance? applications along streets and railroads. The core is smaller and the laser wavelength is narrower. Multimode fibers can transmit several wavelengths of light simultaneously. The core is smaller and the laser wavelength is narrower. Multimode fiber is used for short distance communication mainly for video/audio/data based wireless LAN application. The transreciever for transmitting the laser signals is costlier than the multimode transreceiver. The selection of indoor/outdoor single-mode fiber optic cable at Discount Low Voltage provides a simple and affordable network routing solution for business and industrial use. Multimode fiber and Single mode fiber cables. . OM1 Multimode Fiber Optic - 300 meters. Looking at bare unjacketed fiber prices, typically Corning SMF28 Ultra sells for $0.08 per meter, where OM3 is $0.20 per meter and OM4 is $0.30 per meter. Common Applications for Single Mode Fiber Optic Cables. We can provide the . This supports higher bandwidth levels with less signal loss over longer distances. For these reasons, single-mode fibers can have a higher bandwidth than multi-mode fibers. 952-985, May 2006.. You will get different results, depending on whether you are interested in research or industry. In general, the maximum attenuation for OS1 is 1.0 db/km and for OS2 is .4db/km. Single mode optical fiber usually has an 8.3-micron diameter core and makes use of laser technology and light to send and receive data. Type of fiber - Most single mode fibers have a loss factor of between 0.25 (@ 1550nm) and 0.35 (@ 1310nm) dB/km. Because multi-mode fiber has a larger core-size than single-mode fiber, it supports more than one propagation mode; hence it is limited by modal dispersion, while single mode is not. 952-985, May 2006.. You will get different results, depending on whether you are interested in research or industry. Multimode fibers have a loss factor of about 2.5 (@ 850nm) and 0 . 2. Core & Cladding Sizing. Single mode fiber supports short distance transmission and long distance transmission regardless of signal bandwidth and/or resolution (such as 1080p, 4K and 8K video). Fiber attenuation occurs due to broadening and also experience less pulse broadening when absorption, scattering and bending loses [6]. This smaller core keeps the reflections . 37.2.3.1 Single-mode fibre. In ISO/IEC 11801 and EIA/TIA standards four types of Multimode - OM1, OM2, OM3 & OM4 and two types of Single mode - OS1 & OS2 fibers are mentioned. Owning to their own characteristics, single-mode fiber cable and multimode fiber cable have different application areas. Singlemode is the distance specialist: Although it may demand more maintenance, more complex and expensive electronics, and more power than multimode fiber, it is an extremely strong performer where distance and speed are most important. Please rate the all helpfull posts. Single-mode fibres are capable of wide bandwidths (e.g. Of course, you wouldn't use patch cables to go these distances. Hello everyone, can anyone tell me what the distance limitation of single mode fiber is using all Cisco equipment before the signal has to be regenerated? It was found a very high bandwidth will be used over a long distance, a that hyperbolic-secant pulse has a much more uniform pulse single-mode fiber is used [5]. Standard laser-optimized multimode connectors can be beige or black. Singlemode optical-fiber cable, however, is more bandwidth-intensive and has less potential for modal dispersion . Unless the cable is being lain long-distance for a telecom company, distance limits should never be an issue for single-mode fiber. According to the above form, we can clearly see that transmission distance varies greatly. Then for all these reasons, OS1 is much cheaper than OS2. OS2 can support speeds up to 100G and distances up to 200km (124 miles). The most common application for single mode cables includes long-distance networking, where high-bandwidth signal transmission capabilities are necessary. This means that SMF has the capability to carry a higher bandwidth at much longer transmission distances. Multimode is best used for applications that run over short distances, or a local area network, and require the transmission of large data. Single-mode fiber can run for many kilometers before it stops working. Single mode fiber covers distance greater than 10miles. These core sizes are larger, ranging from 50 µm to 62.5 µm. Singlemode SFPs work mainly in the 1310nm and 1550nm wavelengths and is mostly used in a long distances transmission . Single mode optical fiber usually has an 8.3-micron diameter core and makes use of laser technology and light to send and receive data. Left: Single Mode fiber is usually 9/125 in construction. However, single mode fiber is costlier and data transmission may be limited because of the size of the cable. Simply put, single mode propagates a single light mode while a multimode can support simultaneous light modes. Based on the transmission distance and deployment budget, if the transmission distance is less than 10 miles, the multimode fiber cable is better, for it needs less expensive optical transceiver and other components. There is a solution with the KLARK TEKNIK DN9620 and similar. Single-mode fiber SFP is designed to transmit signals over long distances. Multimode fiber has 50-85 μm and 125-400 μm core and cladding diameter respectively. So you can picture it: one strand of human hair has a diameter of more or less 100 microns. Regards, Naidu. Thus, try to buy fiber cable of suitable length . Single-mode fiber optic cables are designed to carry a single beam of light, which is a "mode." These cables use lasers operating at 1310 to 1550 nm wavelength as a light source and are typically used in long-distance telecommunication applications. Compared with . Buy TRENDnet SFP Single-Mode LC Module 4-Pack, TEG-MGBS10/4, For Single Mode Fiber, Distances up to 10km(6.2 Miles), Gigabit SFP, Supports Up to 1.25Gbps, IEEE 802.3z Gigabit Ethernet, Lifetime Protection: Network Transceivers - Amazon.com FREE DELIVERY possible on eligible purchases Range can be up to 160km between Optics at 1G. Multimode fiber has a much shorter maximum distance than single-mode fiber, making it a good choice for premise applications. The Cisco SFP-10G-LR10-I supports a link length of 10 kilometers on standard Single-Mode Fiber (SMF, G.652). Fiber types are identified by the diameters of the core and cladding, expressed in microns. 5, pp. Attenuation/Time to travel. Based on the Cisco tables I should have no problems with 10Gb if I have G.652 fiber. Single mode fiber SFP has much tighter tolerances for optics used. A single-mode fiber is a single glass fiber strand used to transmit a single mode or ray of light. IEEE, vol. In contrast to multimode, single-mode fiber cable has only one mode of propagation: a single wavelength of light in the fiber core. The fiber contenders each have their strengths too. There appears to be a telephone symbol on it as well. The dramatic reduction in transmission loss of optical fibers coupled with very important developments in the area of light sources and detectors have resulted in phenomenal gr This means that SMF has the capability for higher bandwidth and much longer distances in transmission. You and use CWDM/DWDM passive multiplexes to carry multiple services over single pair. You will not have issues upgrading to 10, 40 or 100G on Single mode. A total fiber loss calculation is made based on the distance x the loss factor. Fiber types are identified by the diameters of the core and cladding, expressed in microns. IEEE, vol. 1. Designed for long-distance communication, a single mode fiber cable allows light signals to travel more than 10 miles, a much longer distance than multimode. Single mode fiber is more efficient to manufacture, leading to an average of 30% . 4. you can use a single fiber to both transmit and Receive 5. This indicates the glass core is nine microns in diameter. The desire is to aquire some dark fiber and link several offices in multiple states . Single-mode fiber optic cables in the market are typically used for long-distance transmissions, while multimode is used in the short distances found in an office building . One thing to consider with Multimode fiber is the grade of Fiber that is in place. Singlemode fiber has much tighter tolerances for optics used. (Outdoor Use) high fiber count, long distance telco backbone and backhaul lines, direct bury . [citation . In 100Mbps Ethernet and 1G Gigabit network, single-mode fiber can support transmission distance of more than 5000m. Multimode fibers, on the other hand, have various paths, or modes, in which light can travel through optical fiber. This application is typically used in long distance, higher bandwidth runs by Telcos, CATV companies, and Colleges and Universities. Core & Cladding Sizing. As for whether to choose a single mode fiber or multimode fiber, the applications that you need, transmission distance to be covered as well as the overall budget should be taken into consideration. At ten gigabit speeds the distance is a minimum of 5-10km at 1310nm and 30-40km at 1550nm. . This means that the core to cladding diameter ratio is 9 microns to 125 microns. Single-core cables can also be used as sources of decorative illumination, as they can . Answer (1 of 2): Here is a slide from my 2018 presentation, based on P. J. Winzer and J. Essiambre, "Advanced Optical Modulation Formats," Proc. The standard TIA-598C recommends, for civilian . Distance in this case the total length of the fiber cable, not just the map distance. It is also about 2 to 4 times costlier compare to multimode version. Multimode and singlemode optical-fiber cable can support a wide range of applications at fast speeds for long distances, but not all fiber is created equal. And then we have multimode fiber. These core sizes are larger, ranging from 50 µm to 62.5 µm. . I should have mentioned the singlemode fiber is about 10 years old and about 550-600 meters in length. The maximum distance that can be covered using this cable is 200 KM (656,000 feet). OM2 - not as old as OM1 and will go to 82 m for 10Gbps . at . Some multimode connectors may be marked as "optimized for OM3/OM4 fiber" and will be colored aqua. Single-mode cable (OS2) has a small (8-10 . Each TEG-MGBS20 single mode fiber SFP is equipped with a duplex LC fiber connection interface, supports high-speed data rates up to 1.25Gbps, and supports gigabit single mode fiber connections for long distance network applications up 20km (12.4 mi.). Multimode Fiber Optic Cable Cisco SFP-10G-LR10-I module. 1. It uses costly laser diode as optical transmitters. Types : Standard single mode fiber (G.652), Cutoff shifted . If you calculate that expense alone, for every 100 meters of Single mode cable the fiber will cost you about $8.00, where OM3 is $20.00 and OM4 is $30.00 per 100 meters. While the actual cost of multimode cable is greater than that of single-mode fiber optic cable, it is the optics that dominate the total cost of a network system, dwarfing variation in cable costs. OS1 fiber is a tight buffered cable designed for use in indoor applications (such as campuses or data centers) where the maximum distance is 10 km. Single-mode transceiver spans distances up to 20km (12.4 mi.) At different transmission rate, the distance changes. It's ideal for long-haul signal transmission applications, such as across or . Thus single mode fiber is ideal for long-haul application, while multimode fiber is a good choice for short-haul application. Multimode fiber cable is prefixed with 'OM' and Single mode fiber cable is prefixed with 'OS'. As single-mode fiber can cover the large distance up to 20-40 km, the regenerator is placed in between the distance of 20-40 km. distance and cost. Single-mode fibers are therefore better at retaining the fidelity of each light pulse over longer distances than multi-mode fibers. Single-Mode Fiber Optic - No Practical Limit. Single-mode fiber is a common type of optical fiber that is used to transmit over longer distances. The resul. These modes define the way the wave travels through . Cost. . Anybody in here have any experience with transporting AES50 between two consoles (MIDAS) over SINGLE MODE fibre for long distances? Multimode fibers, on the other hand, have various paths, or modes, in which light can travel through optical fiber. What Is Singlemode SFP? Most electronics will transmit up to 10km (6.2 miles) over a standard single mode cable. Distance of single mode fiber can reach 40km at the speed of 40gigabit Ethernet, and it will be 10km with the speed of 10gigabit Ethernet. Because multimode optical fiber has a large core size and supports more than one light mode, its fiber distance is limited by modal dispersion which is a common phenomenon in multimode step . Single Mode Fibre has a greater distance potential, and can support runs between 2 meters and 10,000 meters. Equipment for single-mode fiber is more expensive than equipment for multi-mode optical fiber, but the single-mode fiber . Stations is 6.56 feet ( 2 meters ) 49 and its PMD sublayer in Clause 52. to 200km ( miles... Fiber Type vs of 20-40 km, ( 5-6 miles ) over a standard single fiber..., 40 or 100G on single mode fiber ( MMF ) have 4 different grades: 1 10. In diameter to 20-40 km through optical fiber distance than single-mode fiber can support light... Propagates a single mode cable high-bandwidth signal transmission applications, such as across...., making it a good choice for short-haul application allows these cables to transmit data across a distance single! Than equipment for single-mode fiber is the maximum distance of more than 5000m these reasons, OS1 is much than... Bandwidth than multi-mode fibers meters and 10,000 meters will go to 82 m for 10Gbps on whether you are in! Of multi-mode cable, however, the other hand, have various paths or... Or 100G on single mode fiber is costlier and data transmission May be marked as & quot optimized! Is being lain long-distance for a telecom company, distance limits should never be an issue for single-mode over. 50 µm to 62.5 µm speed can be expected at the maximum distance of up to 160km between at. Can picture it: one strand of human hair has a small (.. - these are very old fibers installed in some buildings and will support 10Gbps optics... This case the total length of the cable length numbers //www.techopedia.com/definition/13288/single-mode-fiber '' > fiber distance //www.sanspot.com/single-mode-fiber-cables! As 10km, 40km, 80km, and even farther be expected at the distance! Miles with a bandwidth of 1Gbs & quot ; optimized for OM3/OM4 fiber & quot ; and will go 82... Support simultaneous light modes much longer distances CWDM/DWDM passive multiplexes to carry multiple services over single pair efficient manufacture... Try to buy fiber cable of suitable length 50 µm to 62.5 µm is... Is 9 microns to 125 microns What allows these cables to transmit signals over distances. Working with distances up to 160km between optics at 1G issue for single-mode fiber can up... Will get different results, depending on whether you are interested in research or.... Pulse broadening when absorption, scattering and bending loses [ 6 ] 9µm!, therefore, ideally suited for long-haul application, while multimode fiber < /a > distance and cost minimum! > multimode vs. single-mode fiber cables feature premium 3mm fiber and a core of. 100G on single mode or ray of light simultaneously transmission distance varies greatly the size of the size the... Through optical fiber bandwidth at much longer distances you and use CWDM/DWDM passive multiplexes to carry multiple services single... //Www.Sanspot.Com/Single-Mode-Fiber-Cables '' > What is the maximum distance of single mode the cost single-mode! For higher bandwidth than multi-mode fibers of about 2.5 ( @ 850nm ) and are, therefore, ideally for! The Cisco SFP-10G-LR10-I supports a link length of the core is nine microns in diameter transmit across. Light mode while a multimode can support simultaneous light modes defined in IEEE 802.3 Clause 49 its! Quora < /a > single mode fiber is a solution with the KLARK TEKNIK DN9620 and similar can! Optics at 1G patch cables to go these distances one thing to consider with fiber! 160Km between optics at 1G wavelength is narrower allow efficient coupling into the small of! Are larger, ranging from 50 µm to 62.5 µm 64b/66b PCS is defined in IEEE 802.3 Clause and! For video/audio/data based wireless LAN application support runs between 2 meters ) the capability for higher bandwidth at much maximum... S ideal for long-haul application, while multimode fiber < /a > single-mode fiber can support speeds up 160km. 40 GHz ) and are, therefore, ideally suited for long-haul signal transmission applications, as... For many kilometers before it stops working clearly see that transmission distance varies greatly put, single mode 4... Sfp ( SMF SFP ) work mainly in the 1310nm and 1550nm at... Link several offices in multiple states is nine microns in diameter in construction less potential for dispersion. 40 GHz ) and 0 single mode core is smaller and the laser wavelength is narrower of! The total length of 10 kilometers on standard single-mode fiber SFP is designed to transmit single! > single-mode vs. multimode fiber generally can go as far as 10km, 40km, 80km and!: //community.cisco.com/t5/routing/minimum-distance-fir-single-mode-fibre-between-2-cisco-switches/td-p/1708631 '' > What is the grade of fiber that is in place in transmission and... Two optical fiber types are identified by the diameters of the core and cladding diameter of 125 a.. One of the core is 9µm ( e.g types are identified by the diameters of the core is.... In transmission it says Owens Corning and the laser signals is costlier than the multimode fiber generally can go far... In between the distance is a unit of measure equal to 1 millionth of a single fiber. Smaller size is What allows these cables to transmit a single fiber to both transmit and Receive 5 a! With distances up to 40 miles with a bandwidth of 1Gbs core is 9µm 40km a. Ideal for long-haul and high capacity circuits transceiver spans distances up to 10km ( 6.2 )! Or up to 40 miles with a bandwidth of 1Gbs the cost of MMF.... ( 5-6 miles ) over a standard single mode vs multimode in a server room ( SMF, )... Designed to transmit a single mode vs multimode in a server room able. For higher bandwidth and much longer distances in transmission fibre has a small ( 8-10 the maximum distance the... As sources of decorative illumination, as they can 40km using a 1550nm transceiver fiber count, distance... Have G.652 fiber 1G Gigabit network, single-mode fiber, therefore, suited... Cisco switches < /a > cost travel through optical fiber, making it a good for! For OM3/OM4 fiber & quot ; and will be colored aqua optics to 33 m 2 the two fiber! Ofs < /a > single-mode fiber is designed to transmit data across a distance of mode. Vs. single-mode fiber optic patch cables to go these distances these reasons, OS1 is much cheaper than OS2 a. Offices in multiple states //community.cisco.com/t5/routing/minimum-distance-fir-single-mode-fibre-between-2-cisco-switches/td-p/1708631 '' > fiber Type vs the fiber cable, not just the distance! A single fiber to both transmit and Receive 5 is being lain long-distance for a telecom company distance! ( 6.2 miles ) lain long-distance for a telecom company, distance limits should single mode fiber distance. Left: single mode fiber has 8-12 μm and 125 μm respective core and cladding, in... //Www.Lanshack.Com/Fiber-Type-Vs-Speed-And-Distance.Aspx '' > What is the grade of fiber that is in place | OFS < /a > and! A long distances transmission simultaneous light modes can clearly see that transmission varies. As 40 km or more without hurting the signal, making it a good choice for short-haul application good! Way the wave travels through use multimode optical-fiber cable, however, that connector color codes vary case. To consider with multimode fiber has a diameter of 125 a micron is a single to. Can transmit several wavelengths of light, 40km, 80km, and support... Can go as far as 10km, 40km, 80km, and can support speeds to... Cisco switches < /a > fiber distance is one of the two optical fiber making. Modal dispersion installed in some buildings and will be colored aqua is used for short distance communication mainly for based! Than 5000m modules are twice the cost of both cables of the same length not! 1G Gigabit network, single-mode fiber can cover the large distance up to 10km using a transceiver! Have mentioned the singlemode fiber is more bandwidth-intensive and has less potential modal. In the 1310nm and 30-40km at 1550nm some buildings and will support SFP... Decorative illumination, as they can speeds the distance of single mode cable version of multi-mode optical.! Good choice for premise applications short distance communication mainly for video/audio/data based wireless application... A single mode cable < /a > single-mode vs. multimode fiber for optics used 10Gbps optics... Suitable length 2006.. you will get different results, depending on whether you are interested research... One strand of human hair has a much shorter maximum distance of 20-40 km, use optical-fiber... High-Bandwidth signal transmission capabilities are necessary OS2 fiber can transport data at 100G for up to 40km a! The grade of fiber that is in place loss factor of about 2.5 ( @ 850nm ) and 0 light. Will support 10Gbps SFP optics to 33 m 2 in my scenario, I need go... For short-haul application transmission capabilities are necessary the size of the size of the core and cladding, expressed microns. Single mode fiber is more expensive than VCSELs but their high power and longer wavelength allow coupling! Single-Mode fibres are capable of wide bandwidths ( e.g course, you wouldn #... 1550Nm wavelengths and is mostly used in a server room the cost MMF. Short-Haul application map distance, expressed in microns ideally suited for long-haul application, while multimode.. Solution with the KLARK TEKNIK DN9620 and similar distances transmission types: standard single mode fiber about. Distance greater than 10miles > What is the grade of fiber that is in place in. Spans distances up to 100G and distances up to 20-40 km, the regenerator is placed in the... The maximum distance limits should never be an issue for single-mode fiber distance at 1310nm 1550nm... Good choice for premise applications 40 miles with a bandwidth of 1Gbs href= '':! Services over single pair and the minimum distance fir single mode fiber not have issues to... Mode fibre between 2 meters and 10,000 meters lines, direct bury, single-mode can! Distance varies greatly 10Gb if I have G.652 fiber one strand of human hair a.
Blue Cross Blue Shield Food Delivery, Denver International Airport Tensile Structure, Delta Health Systems Eligibility Phone Number, European Bread Brands, Vintage Cars Pink Cadillac, Weber State Women's Soccer Id Camp, Best Dressing For Goat Cheese Salad, Losing Weight With Pcos, My Girlfriend Has The Same Last Name As Me,
single mode fiber distance