What is Fiber: Definition and 224 Discussions

Fiber or fibre (from Latin: fibra) is a natural or man-made substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene.
Synthetic fibers can often be produced very cheaply and in large amounts compared to natural fibers, but for clothing natural fibers can give some benefits, such as comfort, over their synthetic counterparts.

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  1. F

    Evaluate the outgoing radiation from an optical fiber on a surface

    The geometric configuration that I am adopting is the following, I hope you understand. The optical fiber is positioned relative to the bottom surface at a height ##a## and an angle ##\alpha## with respect to the y-axis in the yz-plane with x = 0. ##b## is the distance between the origin and...
  2. Euge

    POTW What is the Relationship Between Fiber Bundles of Spheres?

    Prove that if there is a fiber bundle ##S^k \to S^m \to S^n##, then ##k = n-1## and ##m = 2n-1##.
  3. M

    I Light coupling from optical fiber to glass?

    Hey everyone, I am trying to couple light from an optical fiber connected to an LED (365nm) into a small glass capillary which is pulled on one end and should be used as a small light source. The idea is to use the glass as a light guide. Has anyone tips for efficient incoupling of the light? I...
  4. X

    B Multimode optical fiber, physics beginner help :D

    Hello ! I have a problem understanding how light works in multimode optical fiber. What do I mean in single-mode optical fiber there is single light which contains information. In multimode there can be multiple lights with multiple information. Like here 1st picture contains multiple...
  5. A

    I Light coupling in fiber optic cables

    Hi Everyone! I have a photonics problem that I was wondering if anyone may be able to shed some light on (no pun intended). I work for a company that is designing a fiber optic emitter/detector as a part of one of our products and we've noticed something that would appear to defy physics...
  6. Thytanium

    A Special Relativity Fiber Bundle: R^3 & Lorentz Metric

    In the space-time of special relativity considered as fiber bundle, could it be stated that the base space is time and the fibers are space ##R^3## related to each other by the Lorentz metric as a connection and in this case would there be parallelism, and in this case: how would this fiber...
  7. Oldman too

    Dark fiber optic cables as Earthquake detectors

    Hello, Recently while familiarizing myself with the rodent menace affecting Fiber optic networks, I came across this rather novel use for the dark, or unused fibers in buried cables. The method apparently holds a lot of promise as well as significant advantages over many current Seismology...
  8. anorlunda

    Squirrels and rats attacking AT&T fiber

    I know that squirrels have always caused more electric power outages than any other cause. Now it is extending to fiber. Whoops.

    I Help Needed for Lens Selection for Fiber optics

    I am using a fiber optic cable through which led light propogate, fiber's half acceptance agle is 30 degree. I want to make the light (diverging)comes out of fiber into collimated beam and this collimated beam will pass through filters, sample and will be used for Fluoroscence application. hope...
  10. O

    Connect: Coupling Light from 2 LEDs into a Single Fiber

    Hi, I am looking for a suitable method to couple light from 2 LEDs into a fiber and then join both fibers, so that I only have one fiber at the end so that both wavelengths can be emitted from a single fiber. The first coupling step from LED into fiber seems to be more easy, I already heard...
  11. sodoyle

    Power Over Fiber for Small Sensors

    I have a "high votage" converter with components at different voltages distributed throughout. I have some sensors that need to be powered in one location that's some distance from its power supply. I want to minimize (or eliminate) the high voltage wires routed throughout the converter. My...
  12. K

    I Gauge Theory and Fiber Bundles

    Hopefully, I am in the right forum. I am trying to get an intuitive understanding of how fiber bundles can describe gauge theories. Gauge fields transform in the adjoint representation and can be decomposed as: Wμ = Wμata Gauge field = Gauge group x generators in the adjoint...
  13. S

    What Causes Molecules to Aggregate Over a Fiber in Optical Trapping?

    I poured a droplet that has 1.55 refractive index (RF) over a fiber that has core and cladding with (RI) 1.45 and 1.4 respectively, and I the molecules aggregated over the fiber, known that because the refractive index of the liquid is higher than of than of the core or the cladding a leakage of...
  14. B

    Coupling Efficiency of LED to Fiber Optic Guide

    Most surface mount types of LED’s have a very nearly cosine distribution of light intensity. If we desire to inject light from an LED to the end of a cylindrical optical guide, what is the coupling efficiency as a function of distance (x) from the end of the guide? Assume that the LED is a...
  15. S

    Elliptical facet cylindrical optical fiber - Mathieu equation

    Let's say I have three modes in a fiber that is elliptical cylinder shaped (cylinder with elliptical facet), as in the image below (the source:Optical Engineering, 46(4), 045003 (2007)) so what is the equations that describe these fields..
  16. E

    Fiber coupling efficiency and general questions regarding ZEMAX

    Hello everyone, a friend and I are working on our master project at a university chair. The project is to set up a free space optics communication (FSO) to, eventually, transmit data. For this we want to couple our laser beam into a fiber at the receiving end, which is then plugged into our...
  17. S

    Polarization of elliptical fiber modes

    If I have three modes in an optical fiber with elliptical facet as shown in the figure, what would be the polarization direction of the modes... what I know that it is linear polarization and could have several configuration.. but what I want really to know that if could be a situation where the...
  18. cianfa72

    I How Do Transition Functions Define a Möbius Strip in Fiber Bundles?

    Hi, starting from this (old) thread I'm a bit confused about the following: the transition function ##ϕ_{12}(b)## is defined just on the intersection ##U_1\cap U_2## and as said in that thread it actually amounts to the 'instructions' to glue together the two charts to obtain the Möbius...
  19. S

    A Evanescent field of a waveguide

    If we look to the figure, in several articles they mentioned that the part of the mode field, the tail of the mode field diameter, travel in the cladding, this maybe I can understand that because of a little change between the refractive indices of the core and the cladding, then the transverse...
  20. cianfa72

    I Galilean spacetime as a fiber bundle

    Hi, reading the book "The Road to Reality" by Roger Penrose I was a bit confused about the notion of Galilean spacetime as fiber bundle (section 17.2). As explained there, each fiber over absolute time ##t## is a copy of ##\mathbf E^3## (an instance of it over each ##t##), there exist no...
  21. A

    Anyone familiar with SFP Fiber Optic Modules?

    I have a question regarding the minimum operating speed of new SFP+ fiber modules. In my line of work, I'm most commonly seeing 10GBASE SFP+ modules installed for network data. Can these modules operate at low speed? Specifically with a PHY capable of only a fraction of the data rate? Further...
  22. DariusP

    Medical Varicose vein treatment with fiber lasers

    So I've read that varicose veins can be treated using fibre lasers. First, anesthetics are used locally to numb the limb and also act as an insulator for heat. Then, a small cut is made and a fiber is guided to the vein. Using laser light somehow the vein shrinks. This is what I don't...
  23. Aagno3

    I How is graded index fiber made ?

    Hey everyone . I was recently studying about fiber optics and it had a little to do with graded index fiber. And its given that the refractive index of the core changes from the axis to the cladding . So , my question is , how is that fiber designed ? It must be quite complicated to carefully...
  24. A

    Optic Fiber Project Ideas for Amateur Physics Student

    Hi everyone! I'm in a physics course from university, we have seen topics related with light and optic, the teacher want a project related with those topics so i have been thinking about a project that involves the optic fiber. I haven't been successful in my research, i find so complicated...
  25. lovethepirk

    Vacuum bag vs bolt force (fabricating a carbon fiber wing)

    Hello, thanks in advance. I'm trying to make a near 100% solid carbon fiber wing. I'm vacuum bagging the top half of the wing and the bottom half of the wing separate. After making sure there is a thin 2mm gap b/w the center of both halves the goal is to put a very strong, thick epoxy between...
  26. kolleamm

    Can I mix carbon fiber fabric with most glues?

    I have a fragile plastic piece and I would like to coat the inner walls with carbon fiber, so I was thinking I could lay carbon fiber on it and put some glue from the hardware store to mix with it. Would it work in making it stronger or do I need a special glue?
  27. cianfa72

    I Product Space vs Fiber Bundle: Understanding the Difference

    Hi, I'm not a really mathematician...I've a doubt about the difference between a trivial example of fiber bundle and the cartesian product space. Consider the product space ## B \times F ## : from sources I read it is an example of trivial fiber bundle with ##B## as base space and ##F## the...
  28. iVenky

    I Single-mode vs multi-mode fiber coupling

    Hi, Is coupling light from a laser into a single-mode fiber (transverse electric) more difficult than coupling to a multi-mode fiber? If so, is it due to the geometry? Does the laser light have multiple modes to begin with or it can be designed to have just one mode? Thanks
  29. Geofleur

    A Pathological example of a Principle Fiber Bundle?

    In Hassani's Mathematical Physics, a principal fiber bundle is defined as shown below. I wanted to see if there is a way to view a tangent bundle as a PFB, even if the resulting structure would have to be globally trivial, so I came up with this idea: Let ##P = {\rm I\!R} \times {\rm l\!R}##...
  30. iVenky

    What's the mode of light in single-mode fiber?

    Hi, We talk about single-mode and multi-mode fiber and I assume they talk about the way of sending just one modes (TEM or TMmn or TEmn). Which mode is generally used for single-mode fiber? Is this set by the geometry of the single-mode fiber (especially the opening)? Also, this means that the...
  31. D

    Tensile yield strength of fiber reinforced plastic

    Hello! I am in a student-run engineering team that heavily utilizes fiber reinforced plastics, and I am just trying to get a better understanding of FRPs. I am wondering how exactly the fiber reinforces the plastic. Let's say the yield strength of the fiber in the 0 degree tensile direction is...
  32. S

    Does Light Travel Through Fiber Optic Cable Generate EMF?

    Does light traveling through a fiber optic cable generate any sort of detectable electromagnetic field? Please forgive the stupid question. It’s something that popped into mind recently and google hasn’t adequately answered for me. I’m not a scientist or physicist. :blushing:
  33. S

    Modes of Optical Fiber propagation

    What actually is a mode of optical fiber propagation?Is it similar to modes which correspond to various configurations as in standing waves on a string ? Also How correct is it to consider no. of rays as no of modes?
  34. T

    Photons in Fiber Optics V Solar Sails

    Solar sails use the push of photons on a mirror. Would it work to use the push of photons in the atoms in fiber optic cables so the question is would there be push and how much on 1 mile of a space train 50 feet wide with 1 foot thick of fiber optics. Here's how I think it would be nearly...
  35. taiwai

    Find out the Young's modulus of a carbon fiber lamina composite

    Hello everyone, nice to be here. I am going to calculate the young modulus of 3 layers of carbon fiber laminar composite For example: 1st: 12K plain wave carbon fiber in 0 degree 2nd:3K till wave carbon fiber in 45deg 3rd:12K plain wave carbon fiber in 0 degree How can I approach to calculate...
  36. mastermechanic

    The cost of a carbon fiber car chassis

    Hello everyone! We're getting prepared to an electromobile car efficiency challange as a team. I'm going to take place in the chassis and exterior design team. I have lots of question but today I'm going to ask one of them. How much does it cost us to produce an ordinary car chassis? I'm...
  37. G

    A Question About Elementary Fiber Bundle Example

    My question regards the classic example of trivial vs non-trivial fiber bundles, the 'cylinder' and the 'Mobius band.' I'm using Nakahara's 'Geometry, Topology, and Physics', specifically Example 9.1. Here's the text: Then he says (and this is the bit where he loses me): My questions are: i)...
  38. Q

    Yang Mills & Fiber Bundles Resource

    Hi everyone, Does anyone know of a good intuitive resource for learning Yang-Mills theory and Fiber Bundles? Ultimately my goal is to gain a geometric understanding of gauge theory generally. I have been studying differential forms and exterior calculus. Thanks!
  39. G

    A Fiber Optics Bandwidth Question

    Hi everyone :] This is my first time here. I have this Quantum Optics question (though I don't believe there is anything QM about this question, so please let me know if I've incorrectly placed this thread) as part of a (nonmarked) assignment. Here's the question: "What is the maximal...
  40. D

    How Is the Minimum Bend Radius of a Fiber Optic Cable Determined?

    If there is a fiber optic cable with a diameter d, the index of refraction of the cladding the cable is given, and so is the index of refraction core of the cable, how would you formulate an equation for the minimum radius of bend the cable can have? Thank you in advance.
  41. T

    Synthetic fibers (rope) that absorb water and shorten

    Hello. I have an engineering idea, an invention. I want to make a watering valve for plants that opens the water when the soil moisture content is too low. I am looking for a material that (1) would not rot, and (2) absorb water and contract at a significant rate to open a valve (millimeter...
  42. nashikin58

    Rotary or centrifugal jet spinning (nanofiber)

    Hi, I am a research student, working on rotary jet spinning. while spinning, nanofibers are formed but it's not attached properly to the collector. It became like a spider web. You guys have any idea why it became like that?
  43. B

    How Do You Calculate the Normalized Frequency for a Multimode Fiber?

    Hi, I'm having trouble calculating the normalized frequency for a multimode fiber. Here's the formula: V=(2π/λ)⋅a⋅√(n12-n22) where λ=900 nm, a=200μm, n1=1.460, n2=1.455 Here's how I plug in the numbers: V=(2π/(900*10-9))⋅(200*10-6)⋅√(1.4602-1.4552)=167This is an easy calculation I know...
  44. M

    How can I determine the length of a Multimode fiber?

    I have a step index SMS (single-multi-single mode fiber) with an equal lateral splicing offset at both junctions. Refractive indexes, offset and radius of cores are given. This device is fed by a broad-band source and the spectral response collected by an Optical Spectrum Analyzer is given...
  45. S

    Max distance of multimode fiber without repeater station

    I have the task to design a system with a multimode fibre optic cable that is 45 km long, but no repeater station. Are optical amplifiers repeater stations? How to get the signal to carry for 45 km? I read that multimode fibres are quite short-range.
  46. DaveC426913

    Will Installing Bell Fibe Alongside Rogers Fibre Optic Cable Cause Interference?

    Just doing due diligence to allay some concerns. If my condo already has Rogers fibre optic cable, and my condo org wants to come in and install a Bell Fibe cable for the hole building, is there any reason to think that this would interfere with the existing Rogers cable? I mean, they're...
  47. I

    Quantum QFT: groups, effective action, fiber bundles, anomalies, EFT

    Hi, I am looking for textbooks in QFT. I studied QFT using Peskin And Schroeder + two year master's degree QFT programme. I want to know about the next items: 1) Lorentz group and Lie group (precise adjectives, group representation and connection between fields and spins from the standpoint of...
  48. KT KIM

    How can light propagate through Hollow optical fiber.

    Now I am studying a bit of optical fibers. And of course generally optical fiber works because of total reflection property of the light, which happens when the light from higher medium hits the lower medium material. However I recently found out that there also is a thing 'Hollow optical...
  49. I

    How to calculate attenuation for optical fiber bundle?

    Hi, If I understood it correctly, the coefficient of attenuation for a single optical fiber, is alpha = (10/L)*log(P(0)/P(L)). Assuming if I knew the properties of the optical fiber and the amount of optical fiber in the bundle, then the total attenuation for the bundle is approximately number...
  50. C

    I keep runing in circles around this optic fiber question....

    Hi everyone I can not seem to get the right formulas to finish this question. I keep on beating my head against a wall for hours now. It just feels like I can not get the right formula to help me out...Is this some sort of trick question? Note if the image does not load here is the link ->...