Fiber Optics

What the big deal anyway? Isn't that just like glass tubes that emit really cool lights when you cut them? More than that, actually, fiber optic cables are the reason why we can connect to the internet, talk to people over long distances and enjoy cable TV. They are also used in medical imaging and mechanical engineering inspection.

How do they transport information anyway?

First of all, we have to know what are the parts of an optic fiber.
Core - this is where the signals travel
Cladding - the thing that reflects signals bck into the core
Buffer coating - outer covering and protection from harsh elements such as moisture which
can destroy the connection
Jacket - holds single optic fiber together



The key here is internal reflection. Yes, reflection *groan*. The information is transmitted as signals, see? So, have you seen a light from laser? The light that goes in a straight path? If you turned it on in a room full of mirrors, the light bounces of to the next mirror, to the next one, so on, so forth, right? Well, signals are like that; they look like "concentrated light rays". Bouncing off the cladding into the core to travel great distances. Th principle used is total internal reflection.

Um... For the meantime, I'll try to understand this principle and tell you about it next time. I need to study for the exams... Ehenh..

Lenses

Steps for Ray Method of Converging Lenses:

1. Draw the first ray parallel to the principal axis. Draw the second ray passing through the vertex. Draw the third ray passing through the focal point in front of the mirror.

2. Based on the three laws of refraction for converging lenses, the ray of refraction for the first ray of incidence must pass through the focal point at the back of the lens, the second ray of incidence must travel a straight line and the thord ray of incidence must form a ray os rafraction parallel to the principal axis.3. The point of intersection is the tip of the object. Just draw a perpendicular line connecting the point of intersection and the principal axis.

Note: 2F is equal to C, so that object is beyond C. To have an idea of what the image of an object placed on another location would look like, just scroll down.

Steps for Ray Method for Diverging Lenses:
1. From the tip of the object, draw the first ray parallel to the principal axis. Draw a second ray that if extended would pass through the focal point of the back side of the mirror. Draw a third ray passing through the vertex.

2. Based on the three laws of refraction for diverging lenses, the ray of refraction for the first incident ray should be going up, tilted to the back side and if extended, would pass through the focal point of the front side of the lens. For the second ray, its ray of refraction must be parallel to the principal axis. For the third ray, it just goes like a straight line.
3. To get an intersection, jut extend the rays of refraction, thet connect the intersection to the principal axis with a perpendicular line, and tadah!!!! There's your image!
credits for the pictures goes to: http://www.glenbrook.k12.il.us/gbssci/phys/Class/refrn/u14l5ea.html