Motheye Anti-Reflective Technology

Q: What is reflectance?

When the light meets the interface at normal incidence, the intensity of light reflected is given by the reflectance, R: 𝑅=(no-ns)/(no+ns)². Where no and ns are the refractive indices of the first and second media, respectively. Increasing refractive index difference leads to increasing reflectance Reflectance can be reduced by decreasing the refractive index difference

Q: What is Motheye AR technology?

The conical nature of nano-structures creates an AR effect Nano-structures are smaller than the wavelength of light • The field of the light wave “sees” combination refractive index (air and glass) As light propagates through the conical nano-structure, the refractive index gradually increases due to the gradual increase in size of the structure (Gradient), leading to very little to no reflected light The AR effect is broad band with no angle dependency, acceptance angles up to 60°

Q: What are the disadvantages of traditional AR coating?

Index matching Lower index films on optical element reduces reflection single or multilayers using destructive interference Multilayer interference Thin film of precise thickness to produce destructive interference multilayer films can reduce reflection to 0.1% or better Highly wavelength dependent Narrow band

Fiberguide Motheye Anti-Reflective Technology involves a random nano-structured surface that is etched into the ends of fibers to reduce reflectance and increase transmission.

Features and Benefits

Improved Transmission and Low Reflectivity

Fiberguide’s patented RARe Motheye Fiber is based on a unique, randomized process that creates nanostructures on the fiber surface. This results in fiber optic cables that can transmit more light, improving signal integrity, because of enhanced anti-reflective properties. The rigorous motheye process produces fiber optic cables that have superior wavelength range, durability and damage thresholds when compared with commonly used AR coatings for fiber optics.

Large Wavelength Range

This means RARe Motheye technology can work for many wavelengths, providing flexibility in terms of meeting various application needs. RARe Motheye nanostructures are about 200nm in height and width. Because this is less than the wavelength of light (400 to 2200nm), the structure is not visible under a microscope. The fiber may appear darker under certain microscopes because light is not reflecting off the surface.

Superior Durability

RARe Motheye has a high laser-induced damage threshold (LIDT) when compared to standard AR coating for fiber optics because the structure is made from the base material of fused silica (see bar graph on the left). Traditional AR thin film coatings are made from alternating dielectric and metal layers and cannot take high LIDT.

Transmission performance data:
The graph below shows the performance of AFS400 round core fiber with no AR coating versus AFS400 round core fiber with RARe Motheye.

Nano-structure depth and width determines AR wavelength limits:
• Depth results in longer wavelength limit
• Width results in short wavelength limit

Licensed proprietary method for optical fibers and end-cap assemblies:
Ensures effective anti-reflective properties

Uses an anti-reflective (AR) structure Modeled after a moth’s eyes, which have low reflectivity to keep the moth hidden from predators:
Reduces reflectance and increases transmission

Overview

Life science OEMs, along with manufacturers of industrial laser equipment that rely on fiber optics risk, light reflecting off the interface, interfering with transmission. Fiberguide Motheye Anti-Reflective Technology employs a proprietary process using nano-structures smaller than light wavelengths to create an anti-reflective effect.

Anti-reflective coatings have low damage thresholds, resulting in improved but still less-than-desirable transmission performance. Fiberguide Motheye Anti-Reflective Technology provides a high damage threshold, allowing for increased energy input and improved durability.

Specifications

Anti-Reflection Type:
Randomized nano surface

Wavelength Range:
400-1550nm

Fiber Sizes:
3µm up to 2.00mm core

Broadband Reflectivity:
<0.5% from 460 to 1550nm over 1090nm

Angle of Incidence:
0 to 60˚

Laser Damage Threshold:
59 J/cm2, Tested at 1064nm, 16.4ns, 20Hz, Spot Diameter 0.405mm

Fiber Types:
All Silica
Optical Fiber
Hard Clad Fiber

Buffer Types:
Acrylate
Aluminum
Gold
Nylon
Polyimide
Tefzel

Assembly Types:
Single Fiber Assemblies
Custom Bundle Assemblies
1D Arrays Connector

Connector Types:
905 SMA
906 SMA
FC/PC
FC/UPC
FC/APC
ST/PC
ST/UPC
ST/APC
Cleaved Ends
Polished Ends
Round 2.5mm Ferrule
FD-80 High Power Connector
905 High Power Connector
1D Arrays
Custom Connector

Frequently Asked Questions

What is reflectance?

When the light meets the interface at normal incidence, the intensity of light reflected is given by the reflectance,
R: 𝑅=(no-ns)/(no+ns)².
Where no and ns are the refractive indices of the first and second media, respectively.

Increasing refractive index difference leads to increasing reflectance
Reflectance can be reduced by decreasing the refractive index difference

What is Motheye AR technology?

The conical nature of nano-structures creates an AR effect

Nano-structures are smaller than the wavelength of light • The field of the light wave “sees” combination refractive index (air and glass)
As light propagates through the conical nano-structure, the refractive index gradually increases due to the gradual increase in size of the structure (Gradient), leading to very little to no reflected light
The AR effect is broad band with no angle dependency, acceptance angles up to 60°

What are the disadvantages of traditional AR coating?

Index matching
Lower index films on optical element reduces reflection single or multilayers using destructive interference
Multilayer interference
Thin film of precise thickness to produce destructive interference multilayer films can reduce reflection to 0.1% or better
Highly wavelength dependent
Narrow band