Garth Naar - Uses of Fibre Optics, Sensors, Lighting and Telecommunications

Optical fibres are one of the wonder materials of the modern industrial age, suitable for a massive range of different applications. Typically they are available in single fibres, bundles of fibres and even more complex layouts with perpendicular angles.

Put simply optical fibres transmit light, normally they are cylindrical in shape and transmit with an efficiency of practically 100%, a result of the internal reflection within the fibres themselves.

 Garth Naar the only impedance to efficiency is cause by impurities in the manufacture of the fibres. Today they are used widely, below are some common applications.

Fibre optic sensors can be used to detect and monitor a range of different physical quantities; typically the sensing is carried out by the changes to the structure of the fibre in response to environmental conditions. A good example is direct strain fibre optic sensors that will monitor physical strain in accordance with the way in which the light reflective properties are affected by changes in the shape of the fibre.

Optical fibres are also used in the telecommunications industry. This is increasingly the case, particularly in developed nations where companies and governments alike are working together to implement fibre optic internet connectivity in towns and cities. The major benefits of using fibre optics for telecommunications cables is that they are flexible, durable and offer far faster data transmission than existing technology.

Garth Naar says Optical fibres are also used extensively within the bio-medical industries and even in manufacturing for imaging purposes, offering insight into hard to reach areas. The ability to send in tiny imaging sensors that relay detailed images back to the user has been instrumental in keyhole surgery and also within manufacturing applications.

Optical fibres are also popular in design circles as a means of lighting interior and exterior spaces. The practicality of this flexible solution is not only easy to install but also offers a range of different lighting effects and styles.

The above information has hoped to point out how useful and practical optical fibres are in the world today. Across myriad industries and a plethora of different applications they are one of the most important technologies used in commerce and industry today

Garth Naar - How to Develop Your Business Strategy

Business strategy is focus

At the real-world level (my favorite), strategy is like driving and sex: we all think we’re pretty good at it. But simplifying, doing today what will seem obvious tomorrow, is genius.

Garth Naar say the best strategies seem obvious as soon as you understand them. Furthermore, it seems to me that if they don’t seem obvious after the fact, they didn’t work.

Strategy has to be easy to define. I like the simple Live Plan method, which I explain here. But aside from that one, I’ve also worked in depth, during my consulting years, with several competing strategy frameworks, and every one of them works well if it’s applied correctly and executed. And furthermore, I say you can also define strategy with a simple summary, story, or a small collection of stories, which I’ll also explain here.

1. The Live Plan simple strategy method

Think of it as the heart of the business, like the heart of the artichoke. It’s a group of core concepts that can’t be separated: problem, solution, market, and identity. Don’t pull them apart. It’s the interrelationship between them that drives your business. Each affects the other three.

Consider a bicycle retail store. Maybe it solves the simple problem of where to buy children’s and family bicycles, service, and accessories, which is one problem. But maybe it solves the problems of the mountain bikers and racers who want a lot of expertise, specialized bicycles, equipment, and know-how, which is a different problem.

You also need to understand what business you’re in. The bicycle store might be helping families with kids bicycles as they grow, or it might be offering real expertise to the serious bikers. Those are different businesses. 

2. The solution: Your product or service

Your solution to that problem is your product or service. Focus on the true desired end result for your customers—the holes too, not just the drill.

Take the bicycle store for example. One solution is a bike store catering to families with children and casual bikers. GarthNaar says Another very different solution is a bike store catering to bicycle enthusiasts, such as serious mountain bikers and racers. It’s not just a bike shop; it’s a general bike shop, or one for families and hobbyists, or one that caters to serious cyclists.

3 The market: Who buys your solution

Your identity influences your choice of target market.

The bike racing shop focuses on attracting enthusiasts, offering expensive high-end bicycles and equipment. The family-focused shop focuses on attracting parents with kids, concentrating on medium-level bikes, trailers, and family-friendly accessories.

Keep your business focused on specific target markets. That bike racer shop owner has to know his products are too expensive for the families, and the families bother the high-end enthusiasts in the shop. Likewise, the family bike shop shouldn’t scare away its target market with very expensive racing bikes.

4. Your business identity (why us)

Every business has its core identity. How are you different from others? What are your strengths and weaknesses? What is your core competence?  What are your goals? What makes you different?

We have the examples above of the varieties of problems, solutions, and markets related to a bicycle store. To understand identity as a part of strategy, think about the difference between a bicycle retail store owned and operated by a former professional bike racer, and another one owned and operated by a couple with children who like cycling as a family activity.

The first one will gravitate toward stocking and selling expensive, sophisticated bicycles for the racing enthusiast and extreme long-distance or mountain biking hobbyist. The second will probably emphasize bicycles for children, bike trailers, carriers, and accessories for families.

Garth Naar - Introduction to Fiber Optics Temperature Measurement

Fiber optics are essentially light pipes. Garth Naar says the group of sensors known as fiber optic thermometers generally refer to those devices measuring higher temperatures wherein blackbody radiation physics are utilized.

Lower temperature targets--say from -100°C to 400°C--can be measured by activating various sensing materials such as phosphors, semiconductors or liquid crystals with fiber optic links offering the environmental and remoteness advantages.

Advantages of Using Fiber Optics for Temperature Measurements

Whether used for communications or infrared temperature measurement, fiber optics offer some inherent advantages for measurements in industrial and/or harsh environments:

- Unaffected by electromagnetic interference (EMI) from large motors, transformers, welders and the like;

- Unaffected by radio frequency interference (RFI) from wireless communications and lightning activity;

- Can be positioned in hard-to-reach or view places;

- Can be focused to measure small or precise locations;

- Does not or will not carry electrical current (ideal for explosive hazard locations);

- Fiber cables can be run in existing conduit, cable trays or be strapped onto beams, pipes or conduit (easily installed for expansions or retrofits);

- Certain cables can handle ambient temperatures to over 300°C--higher with air or water purging.

Monitoring SystemMonitoring Systems

Non-contact infrared thermal monitoring systems that represent a unique technological approach for monitoring and controlling process temperatures. These units combine fiber optics or line-of-sight optics with advanced electronic technology into a system that continuously monitors infrared radiation (a function of temperature) in real time and without physically contacting the target material. The result is a highly reliable system offering outstanding accuracy and repeatability with high response speed.

Fiber Optics Applications

Fiber optic thermometers have proven invaluable in measuring temperatures in basic metals and glass productions as well as in the initial hot forming processes for such materials. Boiler burner flames and tube temperatures as well as critical turbine areas are typical applications in power generation operations. Rolling lines in steel and other fabricated metal plants also pose harsh conditions which are well handled by fiber optics.

Typical applications include furnaces of all sorts, sintering operations, ovens and kilns. Automated welding, brazing and annealing equipment often generate large electrical fields which can disturb conventional sensors.

High temperature processing operations in cement, refractory and chemical industries often use fiber optic temperature sensing. At somewhat lesser temperatures, plastics processing, paper making and food processing operations are making more use of the technology. Fiber optics are also used in fusion, sputtering, and crystal growth processes in the semiconductor industry.

Beyond direct radiant energy collection or two-color methods, fiber optic glasses can be doped to serve directly as radiation emitters at hot spots so that the fiber optics serve as both the sensor and the media. Westinghouse has developed such an approach for distributed temperature monitoring in nuclear reactors. A similar approach can be used for fire detection around turbines or jet engines. Internal "hot spot" reflecting circuitry has been incorporated to determine the location of the hot area.

Garth Naar said an activated temperature measuring system involves a sensing head containing a luminescing phosphor attached at the tip of an optical fiber. A pulsed light source from the instrument package excites the phosphor to luminescence and the decay rate of the luminescence is dependent on the temperature. These methods work well for non-glowing, but hot surfaces below about 400°C.

Garth Naar - The Construction of the Fibre Optic Cables

Fibre optic technology relies on the fact that it is possible to send a light beam along a thin fibre suitably constructed. A fibre optic cable consists of a glass or silica core. The core of the optical fibre is surrounded by a similar material, i.e. glass or silica, called the cladding, that has a refractive index that is slightly lower than that of the core. Garth Naar says it is found that even when the cladding has a slightly higher refractive index, the light passing down the core undergoes total internal reflection, and it is thereby contained within the core of the optical fibre.

The Outside the cladding there is placed a plastic jacket. This is used to provide protection to the optical fibre itself. In addition to this, optical fibres are usually grouped together in bundles and these are protected by an overall outer sheath. This not only provides further protection but also serves to keep the optical fibres together.

Optical fibre types

There is a variety of different types of fibre optic cable that can be used, and there are a number of ways in which types may be differentiated. There are two major categories:

Step index fibre optic cabling

Graded index fibre optic cabling

The step index cable refers to cable in which there is a step change in the refractive index between the core and the cladding. This type is the more commonly used. The other type, as indicated by the name, changes more gradually over the diameter of the fibre. Using this type of cable, the light is refracted towards the centre of the cable.

Optical fibres or optical fibers can also be split into single mode fibre, and multimode fibre. Mention of both single mode fiber and multi-mode fiber is often seen in the literature.

Single mode fiber     This form of optical fibre is the type that is virtually exclusively used these days. It is found that if the diameter of the optical fibre is reduced to a few wavelengths of light, then the light can only propagate in a straight line and does not bounce from side to side of the fibre. As the light can only travel in this single mode, this type of cable is called a single mode fibre. Typically single mode fibre core are around eight to ten microns in diameter, much smaller than a hair.

Single mode fiber does not suffer from multi-modal dispersion and this means that it has a much wider bandwidth. Garth Naar says the main limitation to the bandwidth is what is termed chromatic dispersion where different colours, i.e. Wavelengths propagate at different speeds. Chromatic dispersion of the optical fibre cable occurs within the centre of the fibre itself. It is found that it is negative for short wavelengths and changes to become positive at longer wavelengths. As a result there is a wavelength for single mode fiber where the dispersions is zero. This generally occurs at a wavelength of around 1310 nm and this is the reason why this wavelength is widely used.

The disadvantage of single mode fibre is that it requires high tolerance to be manufactured and this increases its cost. Against this the fact that it offers superior performance, especially for long runs means that much development of single mode fiber has been undertaken to reduce the costs.

Multimode fiber     This form of fibre has a greater diameter than single mode fibre, being typically around 50 microns in diameter, and this makes them easier to manufacture than the single mode fibres.

Multimode optical fiber has a number of advantages. As it has a wider diameter than single mode fibre it can capture light from the light source and pass it to the receiver with a high level of efficiency. As a result it can be used with low cost light emitting diodes. In addition to this the greater diameter means that high precision connectors are not required. However this form of optical fibre cabling suffers from a higher level of loss than single mode fibre and in view of this its use is more costly than might be expected at first sight. It also suffers from multi-mode modal dispersion and this severely limits the usable bandwidth. As a result it has not been widely used since the mid 1980s. Single mode fiber cable is the preferred type.

Attenuation within an optical fibre

Although fibre optic cables offer a far superior performance to that which can be achieved with other forms of cable, they nevertheless suffer from some levels of attenuation. This is caused by several effects:

Loss associated with the impurities     There will always be some level of impurity in the core of the optical fibre. This will cause some absorption of the light within the fibre. One major impurity is water that remains in the fibre.

Loss associated with the cladding     When light reflects off the interface between the cladding and the core, the light will actually travel into the core a small distance before being reflected back. This process causes a small but significant level of loss and is one of the main contributors to the overall attenuation of a signal along an fibre optic cable.

Loss associated with the wavelength     It is found that the level of signal attenuation in the optical fibre depends the wavelength used. The level increases at certain wavelengths as a result of certain impurities.

Despite the fact that attenuation is an issue, it is nevertheless possible to transmit data along single mode fibres for considerable distances. Lines carrying data rates up to 50 Gbps are able to cover distances of 100 km without the need for amplification.