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Endlessly Single Mode, Large-Mode-Area-Fiber

  • Single Mode at All Wavelengths
  • Pure Silica Core and Cladding
  • Available with Core Sizes from Ø5 µm to Ø25 µm




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ESM/LMA Fiber Chart


  • Endlessly Single Mode Operation - No Higher Order Mode Cut-Off
  • Polarization-Maintaining Versions Available
  • Handles Very High Average Power
    as well as High Peak Power
  • Low Nonlinearities
  • Low Fiber Loss
  • Mode Field Diameter is Wavelength Independent
  • Available with Core Sizes from 5 to 25 μm


  • Delivery of High-Power Broadband Radiation in a Single Spatial Mode
  • Short Pulse Delivery
  • Mode Filtering
  • Laser Pigtailing
  • Multiwavelength Guidance
  • Sensors and Interferometers

Thorlabs offers a selection of Endlessly Single Mode (ESM), Large-Mode-Area (LMA) Photonic Crystal Fibers (PCFs), including Polarization-Maintaining (PM) versions. A conventional single mode fiber is actually multimode for wavelengths shorter than the second-mode cutoff wavelength, limiting the useful operating wavelength range in many applications. In contrast, Crystal Fibre's endlessly single mode PCFs are truly single mode at all wavelengths for which fused silica is transparent.

Optical Fiber Manufacturing

In practice, the useful operating wavelength range is limited only by bend loss. Although the cladding possesses six-fold symmetry, the mode profile is very similar to the quasi-Gaussian fundamental mode of a conventional, axially symmetric, step-index fiber, resulting in a form overlap that is >90%. Unlike conventional fibers, these fibers are fabricated from a single material - undoped, high-purity, fused silica glass. The combination of material and very large mode area enables high power levels to be transmitted through the fiber without material damage or the adverse effects caused by the fiber's nonlinear properties. These fibers are sold based on the overall optical specifications and not the physical structure.

Please note that these fibers will ship with both ends sealed in order to prevent moisture and dust from entering the hollow capillary structure during storage. It is necessary to cleave them prior to use using, for example, our S90R Ruby Fiber Scribe or our Vytran® CAC400 Compact Fiber Cleaver.

Endlessly Single Mode, Large-Mode-Area, Single Mode, Photonic Crystal Fiber

Item # ESM-12B LMA-20 LMA-25
Optical Properties
Mode Field Diametera 10.3 ± 1 µm @ 1064 nm
10.5 ± 1 µm @ 1550 nm
16.4 ± 1.5 µm @ 780 nm
16.5 ± 1.5 µm @ 1064 nm
20.6 ± 2.0 µm @ 780 nm
20.9 ± 2.0 µm @ 1064 nm
Single Mode Cut-Off Wavelength Noneb
Attenuationc <3 dB/km @ 1550 nm
<8 dB/km @ 1064 nm
<20 dB/km @ 780 nm
<5 dB/km @ 1064 nm
<7 dB/km @ 780 nm
<25 dB/km @ 632 nm
<5 dB/km @ 1064 nm
<2 dB/km @ 1550 nm
(Click for Details)
Numerical Aperture (5%) 0.09 ± 0.02 @ 1064 nm 0.06 ± 0.02 @ 1064 nm 0.048 ± 0.02 @ 1064 nm
Mode Field Area - ~215 µm2 ~265 µm 2
Core Index Proprietaryd
Cladding Index Proprietaryd
Physical Properties
Signal Core Diametere 12.2 ± 0.5 µm 19.9 ± 0.5 μm 25.1 ± 0.5 μm
Outer Cladding Diameter, OD 125 ± 5 µm 230 ± 5 μm 258 ± 5 μm
Coating Diameter 245 ± 10 µm 350 ± 10 μm 342 ± 10 μm
Cladding Material Pure Silica
Coating Material Acrylate, Single Layer
Proof Test Level 0.5% 0.33% 0.33%
  • Full width at points in the near field where intensity has dropped to 1/e2 of the peak value.
  • TIA-455-80-C Standard
  • Measured for a bend radius of 16 cm.
  • We regret that we cannot provide this proprietary information.
  • This specification is the geometrical (or physical) core diameter of the fiber.

Endlessly Single Mode, Large-Mode-Area, Polarization-Maintaining, Photonic Crystal Fiber

Item # LMA-PM-5 LMA-PM-10 LMA-PM-15
Optical Properties
Mode Field Diametera 4.2 ± 0.5 μm @ 532 nm
4.4 ± 0.5 μm @ 1064 nm
8.4 ± 1.0 μm @ 532 nm
8.6 ± 1.0 μm @ 1064 nm
12.2 ± 1.5 μm @ 532 nm
12.6 ± 1.5 μm @ 1064 nm
Attenuation <40 dB/km @ 532 nmb
<10 dB/km @ 632 nm
<7 dB/km @ 1064 nm
<25 dB/km @ 532 nmb
<15 dB/km @ 632 nm
<5 dB/km @ 1064 nm
<10 dB/km @ 1064 nm
(Click for Details)
Numerical Aperture 0.20 (typical) @ 1064 nm 0.12 ± 0.02 @ 1064 nm 0.04 ± 0.02 @ 532 nm
0.07 ± 0.02 @ 1064 nm
Cut-off Wavelength None
Core Index Proprietaryc
Cladding Index Proprietaryc
Physical Properties
Signal Core Diameterd 5.0 ± 0.5 μm 10.0 ± 0.5 μm 14.8 ± 0.8 μm
Outer Cladding Diameter, OD 125 ± 2 μm 230 ± 5 μm 230 ± 5 μm
Coating Diameter 245 ± 10 μm 350 ± 10 μm 350 ± 10 μm
Cladding Material Pure Silica
Coating Material Acrylate, Single Layer
Proof Test Level 0.5% 0.33%
  • Full width at points in the near field where intensity has dropped to 1/e2 of the peak value.
  • Measured for a bend radius of 8 cm.
  • We regret that we cannot provide this proprietary information.
  • This specification is the geometrical (or physical) core diameter of the fiber.

This application note addresses general handling of fibers from NKT Photonics, including how to strip the protective coating, how to cleave the fibers and tips for coupling light to and from the fibers. This is ideal for customers new to photonic crystal fibers.


The application note below addresses general advice about fusion splicing of photonic crystal fibers (PCFs). The note is limited to the work related directly to the fusion splicer, whereas guidelines for general handling of the PCFs can be found in the application note to the left.

Application Note-_Splicing_Single Mode_PCF.pdf

Laser-Induced Damage in Silica Optical Fibers

The following tutorial details damage mechanisms relevant to unterminated (bare) fiber, terminated optical fiber, and other fiber components from laser light sources. These mechanisms include damage that occurs at the air / glass interface (when free-space coupling or when using connectors) and in the optical fiber itself. A fiber component, such as a bare fiber, patch cable, or fused coupler, may have multiple potential avenues for damage (e.g., connectors, fiber end faces, and the device itself). The maximum power that a fiber can handle will always be limited by the lowest limit of any of these damage mechanisms.

While the damage threshold can be estimated using scaling relations and general rules, absolute damage thresholds in optical fibers are very application dependent and user specific. Users can use this guide to estimate a safe power level that minimizes the risk of damage. Following all appropriate preparation and handling guidelines, users should be able to operate a fiber component up to the specified maximum power level; if no maximum is specified for a component, users should abide by the "practical safe level" described below for safe operation of the component. Factors that can reduce power handling and cause damage to a fiber component include, but are not limited to, misalignment during fiber coupling, contamination of the fiber end face, or imperfections in the fiber itself. For further discussion about an optical fiber’s power handling abilities for a specific application, please contact Thorlabs’ Tech Support.

Power Handling Limitations Imposed by Optical Fiber
Click to Enlarge

Undamaged Fiber End
Power Handling Limitations Imposed by Optical Fiber
Click to Enlarge

Damaged Fiber End

Damage at the Air / Glass Interface

There are several potential damage mechanisms that can occur at the air / glass interface. Light is incident on this interface when free-space coupling or when two fibers are mated using optical connectors. High-intensity light can damage the end face leading to reduced power handling and permanent damage to the fiber. For fibers terminated with optical connectors where the connectors are fixed to the fiber ends using epoxy, the heat generated by high-intensity light can burn the epoxy and leave residues on the fiber facet directly in the beam path.

Estimated Optical Power Densities on Air / Glass Interfacea
Type Theoretical Damage Thresholdb Practical Safe Levelc
(Average Power)
~1 MW/cm2 ~250 kW/cm2
10 ns Pulsed
(Peak Power)
~5 GW/cm2 ~1 GW/cm2
  • All values are specified for unterminated (bare) silica fiber and apply for free space coupling into a clean fiber end face.
  • This is an estimated maximum power density that can be incident on a fiber end face without risking damage. Verification of the performance and reliability of fiber components in the system before operating at high power must be done by the user, as it is highly system dependent.
  • This is the estimated safe optical power density that can be incident on a fiber end face without damaging the fiber under most operating conditions.

Damage Mechanisms on the Bare Fiber End Face

Damage mechanisms on a fiber end face can be modeled similarly to bulk optics, and industry-standard damage thresholds for UV Fused Silica substrates can be applied to silica-based fiber. However, unlike bulk optics, the relevant surface areas and beam diameters involved at the air / glass interface of an optical fiber are very small, particularly for coupling into single mode (SM) fiber. therefore, for a given power density, the power incident on the fiber needs to be lower for a smaller beam diameter.

The table to the right lists two thresholds for optical power densities: a theoretical damage threshold and a "practical safe level". In general, the theoretical damage threshold represents the estimated maximum power density that can be incident on the fiber end face without risking damage with very good fiber end face and coupling conditions. The "practical safe level" power density represents minimal risk of fiber damage. Operating a fiber or component beyond the practical safe level is possible, but users must follow the appropriate handling instructions and verify performance at low powers prior to use.

Calculating the Effective Area for Single Mode and Multimode Fibers
The effective area for single mode (SM) fiber is defined by the mode field diameter (MFD), which is the cross-sectional area through which light propagates in the fiber; this area includes the fiber core and also a portion of the cladding. To achieve good efficiency when coupling into a single mode fiber, the diameter of the input beam must match the MFD of the fiber.

As an example, SM400 single mode fiber has a mode field diameter (MFD) of ~Ø3 µm operating at 400 nm, while the MFD for SMF-28 Ultra single mode fiber operating at 1550 nm is Ø10.5 µm. The effective area for these fibers can be calculated as follows:

SM400 Fiber: Area = Pi x (MFD/2)2 = Pi x (1.5 µm)2 = 7.07 µm= 7.07 x 10-8 cm2

 SMF-28 Ultra Fiber: Area = Pi x (MFD/2)2 = Pi x (5.25 µm)2 = 86.6 µm= 8.66 x 10-7 cm2

To estimate the power level that a fiber facet can handle, the power density is multiplied by the effective area. Please note that this calculation assumes a uniform intensity profile, but most laser beams exhibit a Gaussian-like shape within single mode fiber, resulting in a higher power density at the center of the beam compared to the edges. Therefore, these calculations will slightly overestimate the power corresponding to the damage threshold or the practical safe level. Using the estimated power densities assuming a CW light source, we can determine the corresponding power levels as:

SM400 Fiber: 7.07 x 10-8 cm2 x 1 MW/cm2 = 7.1 x 10-8 MW = 71 mW (Theoretical Damage Threshold)
     7.07 x 10-8 cm2 x 250 kW/cm2 = 1.8 x 10-5 kW = 18 mW (Practical Safe Level)

SMF-28 Ultra Fiber: 8.66 x 10-7 cm2 x 1 MW/cm2 = 8.7 x 10-7 MW = 870 mW (Theoretical Damage Threshold)
           8.66 x 10-7 cm2 x 250 kW/cm2 = 2.1 x 10-4 kW = 210 mW (Practical Safe Level)

The effective area of a multimode (MM) fiber is defined by the core diameter, which is typically far larger than the MFD of an SM fiber. For optimal coupling, Thorlabs recommends focusing a beam to a spot roughly 70 - 80% of the core diameter. The larger effective area of MM fibers lowers the power density on the fiber end face, allowing higher optical powers (typically on the order of kilowatts) to be coupled into multimode fiber without damage.

Damage Mechanisms Related to Ferrule / Connector Termination

Click to Enlarge
Plot showing approximate input power that can be incident on a single mode silica optical fiber with a termination. Each line shows the estimated power level due to a specific damage mechanism. The maximum power handling is limited by the lowest power level from all relevant damage mechanisms (indicated by a solid line).

Fibers terminated with optical connectors have additional power handling considerations. Fiber is typically terminated using epoxy to bond the fiber to a ceramic or steel ferrule. When light is coupled into the fiber through a connector, light that does not enter the core and propagate down the fiber is scattered into the outer layers of the fiber, into the ferrule, and the epoxy used to hold the fiber in the ferrule. If the light is intense enough, it can burn the epoxy, causing it to vaporize and deposit a residue on the face of the connector. This results in localized absorption sites on the fiber end face that reduce coupling efficiency and increase scattering, causing further damage.

For several reasons, epoxy-related damage is dependent on the wavelength. In general, light scatters more strongly at short wavelengths than at longer wavelengths. Misalignment when coupling is also more likely due to the small MFD of short-wavelength SM fiber that also produces more scattered light.

To minimize the risk of burning the epoxy, fiber connectors can be constructed to have an epoxy-free air gap between the optical fiber and ferrule near the fiber end face. Our high-power multimode fiber patch cables use connectors with this design feature.

Determining Power Handling with Multiple Damage Mechanisms

When fiber cables or components have multiple avenues for damage (e.g., fiber patch cables), the maximum power handling is always limited by the lowest damage threshold that is relevant to the fiber component. In general, this represents the highest input power that can be incident on the patch cable end face and not the coupled output power.

As an illustrative example, the graph to the right shows an estimate of the power handling limitations of a single mode fiber patch cable due to damage to the fiber end face and damage via an optical connector. The total input power handling of a terminated fiber at a given wavelength is limited by the lower of the two limitations at any given wavelength (indicated by the solid lines). A single mode fiber operating at around 488 nm is primarily limited by damage to the fiber end face (blue solid line), but fibers operating at 1550 nm are limited by damage to the optical connector (red solid line).

In the case of a multimode fiber, the effective mode area is defined by the core diameter, which is larger than the effective mode area for SM fiber. This results in a lower power density on the fiber end face and allows higher optical powers (on the order of kilowatts) to be coupled into the fiber without damage (not shown in graph). However, the damage limit of the ferrule / connector termination remains unchanged and as a result, the maximum power handling for a multimode fiber is limited by the ferrule and connector termination. 

Please note that these are rough estimates of power levels where damage is very unlikely with proper handling and alignment procedures. It is worth noting that optical fibers are frequently used at power levels above those described here. However, these applications typically require expert users and testing at lower powers first to minimize risk of damage. Even still, optical fiber components should be considered a consumable lab supply if used at high power levels.

Intrinsic Damage Threshold

In addition to damage mechanisms at the air / glass interface, optical fibers also display power handling limitations due to damage mechanisms within the optical fiber itself. These limitations will affect all fiber components as they are intrinsic to the fiber itself. Two categories of damage within the fiber are damage from bend losses and damage from photodarkening. 

Bend Losses
Bend losses occur when a fiber is bent to a point where light traveling in the core is incident on the core/cladding interface at an angle higher than the critical angle, making total internal reflection impossible. Under these circumstances, light escapes the fiber, often in a localized area. The light escaping the fiber typically has a high power density, which burns the fiber coating as well as any surrounding furcation tubing.

A special category of optical fiber, called double-clad fiber, can reduce the risk of bend-loss damage by allowing the fiber’s cladding (2nd layer) to also function as a waveguide in addition to the core. By making the critical angle of the cladding/coating interface higher than the critical angle of the core/clad interface, light that escapes the core is loosely confined within the cladding. It will then leak out over a distance of centimeters or meters instead of at one localized spot within the fiber, minimizing the risk of damage. Thorlabs manufactures and sells 0.22 NA double-clad multimode fiber, which boasts very high, megawatt range power handling.

A second damage mechanism, called photodarkening or solarization, can occur in fibers used with ultraviolet or short-wavelength visible light, particularly those with germanium-doped cores. Fibers used at these wavelengths will experience increased attenuation over time. The mechanism that causes photodarkening is largely unknown, but several fiber designs have been developed to mitigate it. For example, fibers with a very low hydroxyl ion (OH) content have been found to resist photodarkening and using other dopants, such as fluorine, can also reduce photodarkening.

Even with the above strategies in place, all fibers eventually experience photodarkening when used with UV or short-wavelength light, and thus, fibers used at these wavelengths should be considered consumables.

Preparation and Handling of Optical Fibers

General Cleaning and Operation Guidelines
These general cleaning and operation guidelines are recommended for all fiber optic products. Users should still follow specific guidelines for an individual product as outlined in the support documentation or manual. Damage threshold calculations only apply when all appropriate cleaning and handling procedures are followed.

  1. All light sources should be turned off prior to installing or integrating optical fibers (terminated or bare). This ensures that focused beams of light are not incident on fragile parts of the connector or fiber, which can possibly cause damage.

  2. The power-handling capability of an optical fiber is directly linked to the quality of the fiber/connector end face. Always inspect the fiber end prior to connecting the fiber to an optical system. The fiber end face should be clean and clear of dirt and other contaminants that can cause scattering of coupled light. Bare fiber should be cleaved prior to use and users should inspect the fiber end to ensure a good quality cleave is achieved.

  3. If an optical fiber is to be spliced into the optical system, users should first verify that the splice is of good quality at a low optical power prior to high-power use. Poor splice quality may increase light scattering at the splice interface, which can be a source of fiber damage.

  4. Users should use low power when aligning the system and optimizing coupling; this minimizes exposure of other parts of the fiber (other than the core) to light. Damage from scattered light can occur if a high power beam is focused on the cladding, coating, or connector.

Tips for Using Fiber at Higher Optical Power
Optical fibers and fiber components should generally be operated within safe power level limits, but under ideal conditions (very good optical alignment and very clean optical end faces), the power handling of a fiber component may be increased. Users must verify the performance and stability of a fiber component within their system prior to increasing input or output power and follow all necessary safety and operation instructions. The tips below are useful suggestions when considering increasing optical power in an optical fiber or component.

  1. Splicing a fiber component into a system using a fiber splicer can increase power handling as it minimizes possibility of air/fiber interface damage. Users should follow all appropriate guidelines to prepare and make a high-quality fiber splice. Poor splices can lead to scattering or regions of highly localized heat at the splice interface that can damage the fiber.

  2. After connecting the fiber or component, the system should be tested and aligned using a light source at low power. The system power can be ramped up slowly to the desired output power while periodically verifying all components are properly aligned and that coupling efficiency is not changing with respect to optical launch power.

  3. Bend losses that result from sharply bending a fiber can cause light to leak from the fiber in the stressed area. When operating at high power, the localized heating that can occur when a large amount of light escapes a small localized area (the stressed region) can damage the fiber. Avoid disturbing or accidently bending fibers during operation to minimize bend losses.

  4. Users should always choose the appropriate optical fiber for a given application. For example, large-mode-area fibers are a good alternative to standard single mode fibers in high-power applications as they provide good beam quality with a larger MFD, decreasing the power density on the air/fiber interface.

  5. Step-index silica single mode fibers are normally not used for ultraviolet light or high-peak-power pulsed applications due to the high spatial power densities associated with these applications.

Posted Comments:
Richard Grote  (posted 2020-11-30 17:47:13.163)
I have been buying LMA-20 from you for sensing applications. I need a short length ie 1m of LMA-20 connectorised on either end with your CF-230 so that I can use it with ADAF2 for some specific applications? Please let me know if you can and if so how fast you can supply it.
YLohia  (posted 2020-12-01 10:29:35.0)
Thank you for contacting Thorlabs. Unfortunately, we cannot offer connectorized versions of these fibers at the moment. I have reached out to you directly to discuss alternatives.
user  (posted 2017-11-20 08:13:41.927)
What does a proof test level of 0.5% means?
tfrisch  (posted 2018-01-19 04:11:29.0)
Hello, thank you for contacting Thorlabs. The percent is a minimum elongation that the fiber would reach under some tension, typically about 50kpsi, though it depends on the fiber diameter. Please reach out to us at if you need to discuss this further.  (posted 2016-10-03 22:18:23.603)
I have been buying LMA-20 from you for sensing applications. I need a short length ie 1m of LMA-20 connectorised on either end with your CF-230 so that I can use it with ADAF2 for some specific applications? Please let me know if you can and if so how fast you can supply it.
jlow  (posted 2016-10-03 01:52:09.0)
Response from Jeremy at Thorlabs: We do not currently offer this service for PCF. I will contact you directly to recommend an alternative.
hawthorne  (posted 2015-09-15 17:26:18.893)
Do you have a measurement or expectation of the attenuation of the LMA PM 5 at 355 nm?
besembeson  (posted 2015-10-01 03:18:07.0)
Response from Bweh at Thorlabs USA: Sorry we don't have such data at this time.
lokirune  (posted 2015-04-30 16:10:12.003)
Hi. I want to connect ESM-12B fiber to FC/APC connetor. I am using 532 nm pulse laser, and couple it to fiber, but having difficulties with fiber damage now. Is it easy to connect this fiber to FC/APC connector? What should I buy more? Thanks.
jlow  (posted 2015-05-07 11:29:25.0)
Response from Jeremy at Thorlabs: We will contact you directly about the connectorization of the PCF.
cbrideau  (posted 2013-09-17 18:57:19.907)
I have to couple a large wavelength range from a tuneable laser source into a fiber and have it single mode or nearly so. My range is 370 to 540nm. What fiber would you suggest? Would LMA-PM-5 work? Rather than ESM fiber, can I use regular SM? I am currently using your SM300 fiber but I am worried it will cut off longer than 430. My power levels are in the 10's of mW.
jlow  (posted 2013-09-19 14:17:00.0)
Response from Jeremy at Thorlabs: For 370nm to 540nm, the SM300 will probably not work since the longer wavelength will probably not be guided and the fiber will be too lossy. The ESM-12B and LMA-PM-5 fiber could possibly work depending on your requirements. I will get in contact with you directly to discuss about your application.
sky.rover  (posted 2013-04-22 00:41:06.067)
I want to buy LMA-PM-10 fiber and the matching FC/APC cable and fiber collimation package using at 1um of the wavelength of light. Do the LMA-PM-10, P3-980PM-FC-2, F280APC-B match? Or any more advice? Thank you.
cdaly  (posted 2013-05-02 13:52:00.0)
Response from Chris at Thorlabs: F280APC-B is pre-aligned for 633nm collimation and would likely not work very well for 1 um. We do have a 1064 version, F220APC-1064, which is a shorter focal length at ~11mm, but if you have a specified wavelength in mind we can also custom align this or possible the 18mm version for you. Please note as well that the LMA-PM-10 is not connectorized and is sold as bare fiber. I will contact you directly to discuss this further.
tcohen  (posted 2012-04-09 11:03:00.0)
Response from Tim at Thorlabs: Thank you for your feedback. For the LMA-PM-10 the attenuation at 470nm will be <30 dB/km measured for a bend radius of 16cm. PCF can be spliced to small core silica fiber. In the “Handling” tab you can find application notes discussing splicing and I have contacted you with some information.
mchen  (posted 2012-04-06 15:03:36.0)
1. If using LMA-10 @ 470nm, the attenuation will be how much? 2. Can this type of fiber be spliced with a regular fiber?
jjurado  (posted 2011-06-27 11:39:00.0)
Response from Javier at Thorlabs to last poster: Thank you very much for submitting your inquiry. The Signal Core Diameter spec for the LMA fibers is really just the geometrical (or physical) core diameter of the fiber. So, for the LMA-20, the core diameter spec is 20 +/- 0.4 um.
jjurado  (posted 2011-06-24 18:52:00.0)
Response from Javier at Thorlabs to last poster: Thank you very much for contacting us. For the LMA (and ESM) fibers, dispersion effects are mainly driven by chromatic dispersion, very much like the dispersion of silica. So, in this case, the amount of waveguide dispersion is minimal. On the other hand, the waveguide of nonlinear PCF fibers is designed such that specific dispersion properties that are needed for supercontinuum and other nonlinear phenomena are achieved.
user  (posted 2011-06-23 17:09:34.0)
I am just wondering why the dispersion curve here is different from the dispersion curve for highly nonlinear PCF. Is the dispersion curve refers to chormatic dispersion or simply material dispersion?
user  (posted 2011-06-23 16:54:16.0)
I am just confuse about the term "signal core diameter". Is it the core diameter? If not, what is the core diameter of the fibre LMA20?
acable  (posted 2008-06-04 14:35:46.0)
One trick, obvious once said, is to ensure that the coupled light field is focused in air in front of the fiber. This ensures that the first waist that forms within the fiber is highly aberrated from the first bounce at the core cladding interface. This results in a lower power density than would be realized if the light field is focused directly on (worst case) or near the outer face of the fiber.
Tyler  (posted 2008-06-04 14:11:20.0)
A response from Tyler at Thorlabs to Daniel: As you know, many factors can influence the power damage threshold. In general, these fibers can be treated similarly to bulk silica, but in practice, things like imperfect coupling, contaminants, and other factors reduce the damage threshold. Each LMA fiber has a different mode field area and thus would have a different damage threshold. A good guideline would be to determine the mode field area and limit the power so that the peak power density is less than the damage threshold of silica, which is on the order of 400GW/cm^2. For safety, a factor of 10 or so might be prudent to use when using the fiber.(i.e, use 40GW/cm^2 as the maximum power density) I know this doesnt really answer your question but there are currently many good people in the industry trying to really understand and quantify damage thresholds so it is not at all a parameter than can be given with precision or guaranteed. If your application will utilize power densities in excess of 40 GW/cm^2 please contact an application engineer at Thorlabs to discuss the products feasibility and to gain access to any recent feedback concerning the damage threshold of the product. To the reader: If you have any experience with the damage threshold of Large Mode Area Fibers please consider posting to this page. It is Thorlabs hope that this forum can become a valuable source of information for the scientific community.
daniel.mclean  (posted 2007-11-19 12:18:39.0)
It would be good if you listed the power handling capability of these fibers.

Endlessly Single Mode, Large-Mode-Area, Single Mode, Photonic Crystal Fiber

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
ESM-12B Support Documentation
ESM-12BESM Large Mode Area Photonic Crystal Fiber, Ø12.2 µm Core
Per Meter
LMA-20 Support Documentation
LMA-20ESM Large Mode Area Photonic Crystal Fiber, Ø19.9 µm Core
Per Meter
LMA-25 Support Documentation
LMA-25ESM Large Mode Area Photonic Crystal Fiber, Ø25.1 µm Core
Per Meter

* Orders for in-stock bare fiber placed by 3:00 PM ET are eligible for same-day shipment.

Endlessly Single Mode, Large-Mode-Area, Polarization-Maintaining, Photonic Crystal Fiber

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LMA-PM-5 Support Documentation
LMA-PM-5ESM Large-Mode-Area PM Photonic Crystal Fiber, Ø5.0 µm Core
Per Meter
LMA-PM-10 Support Documentation
LMA-PM-10ESM Large-Mode-Area PM Photonic Crystal Fiber, Ø10.0 µm Core
Per Meter
LMA-PM-15 Support Documentation
LMA-PM-15ESM Large-Mode-Area PM Photonic Crystal Fiber, Ø14.8 µm Core
Per Meter

* Orders for in-stock bare fiber placed by 3:00 PM ET are eligible for same-day shipment.

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