Average rainfall 2001-2016, global tropics

Map: Average rainfall 2001-2016, global tropics

blog: Fiber optical cables for light

Introduction

For steering and capturing light for my handheld spectrometer I started to look for fibre (or light) optical cables. There are many alternative materials and solutions for light transmission using optical cables. This post is an attempt to come to grips with these alternatives.

A good page with Q and A from thefiberopticstore.

Optical data transmission cable

If you search for fibre optical cables the chances are your result will be some optical audio cable (or TOSlink cable). These are data transmission cables, usually quoted to a diameter equal three human hairs.

TOSlink digital audio optical cable with JIS F05 connector.
Illustration of the layers of a typical TOSlink cable, the central light transmission has a width of approximately 3 human hairs.

While these cables do their job, the amount of light that passes is very small. The quality is high but the losses along the cable can be large. A second problem is that the light cone exiting the TOSlink is not focused but dispersed, and the already quite small amount of light disperse even further.

Optical light cable

In contrast to fibre optical data cables, optical light cables come in various sizes (diameters) and are used for transmitting light as a source of illumination. These cables are typically either bare, or coated in black plastic. They can have any diameter, but commonly they are 0.25, 0.5, 0.75, 1.0, 1.5, 2, 3, 4 … and further steps of 1 mm.

PMMA plastic optic fiber.

Materials include PMMA plastic …

Transmission of light cable materials.

Buying

In Sweden I can only find LedVision AB that sell light optical cables. The cables they sell are PMMA.

LedVision AB saluför också linser/kristaller att sätta på änden för olika ändamål.

I do not think it necessary, but you can get holders for optical fibres from for instance elfa ([or here]https://www.elfa.se/sv/ljusledare-mentor-1316-2001/p/11055283?channel=b2c&price_gs=36.375&wt_mc=se.cse.gshop.sv.-&source=googleps&ext_cid=shgooaqsesv-blcss&kw=%7Bkeyword%7D&ext_cid=shgooaqsesv-P-CSS-Shopping-MainCampaign-Optoelectronics&gclid=CjwKCAjwg6b0BRBMEiwANd1_SOysNX86CkA7_mTNt0XN9FHUsvwil_QXWlhcdIYoD5mcn2VZMZ88YBoCAzwQAvD_BwE) and Conrad.se. To search for the holders in Swedish use the term “ljusledare”.

Cutting

For the smallest size, use a scissor, up to 4-5 mm use a small wire cutter, and for even thicker use a bolt cutter. Then use a fine grained ]sandpaper of nail emery board to smooth](https://thefiberopticstore.com/faq/do-the-ends-of-the-fiber-need-to-be-polished/) the ends of optical fibre.