Name: Gabriel Caceres Course No: 351 Lab section: L1

Partner(s): Chris Kinne and Laura Luloff

Date: 02/24 01/17 Experiment Number: ? Grade: 77->32

l-42

Title of Experiment: Fiber Optics

Object of Experiemnt: The object of the experiment is to study some of the basic properties of fiber optic cables and of the electronics required to transmit and receive the light signals. speed of light -1

Identification of Apparatus:

·  Power Supply

·  Voltmeters

·  Batteries

·  Fiber optics

·  Transmitter

·  Receiver

·  Speaker

·  function generator -1

orig data -3

Summary of Results:

Overall, our results did not come out particularly good, but this lab usually has a pretty margin of error. When we damaged the fiber, we did see the transmission ration decrease as expected.

what were your results? -4

Discussion:

The energy lost through the wiring and the circuitry was a big source of error in this lab.

Questions and Results:

I) Basic Properties

a) When the 20 cm piece of fiber was inserted into the fiber connection, the opposite end of the fiber emitted light, but no light escaped the fiber through the sides

b) As the modulation input changed, the intensity of the light emitted by the fiber changed, and the light had maximum and minimum intensities

c) The output voltage directly depended on the gain setting of the receiver. As the gain increased so did the output voltage

d) The output voltage from connecting the 10 cm and 20 cm fibers was much lower than that of the 30 cm fiber. Since air is between the 10 cm and the 20 cm fibers, and air has a refraction index of 1.00, a smaller amount of light was transferred. Similarly when water filled the connection between the two fibers, less light was transmitted because water’s higher index of refraction, 1.33, but more light was transmitted through the water than without it because water’s index of refraction is greater that air’s. why n matter? -1

e) The results from the graph in Origin were slightly off from any function, but ignoring lengths 2 m and 5 m, the output voltage decreased as the lengths of fiber increased. The values that did not fit in the graph most likely were due to error from damaged fibers. bigger? -1

f) The tighter the fiber is bent, the less output voltage. The Critical angle for total internal reflection for this fiber is about 42.16 degrees, which means that light traveling through the fiber will be completely internally reflected as long as light hitting the boundary between the fiber and air strikes at an angle less than 42.16 degrees.

g) After scraping the surface of the cable, the amplitude of the signal decreased and we could see light escaping from the cuts in the fiber. After making a deep scratch on the fiber, hardly any light was transmitted through the whole length of the cable. Most of the light escaped through the deep scratch. wht=y? -1

h) If too much light is transmitted, i.e. the intensity is too large, then the sin wave gets cut off on top, so it has a limit. Also there is a bottom limit of zero, because the amount of light cannot be negative.

II) Speed of Light

Using the change in lengths of fibers and the time shift, the speed of light in the fiber was found to be 5.00e7 m/s. Then using that value, the index of refraction of the fiber was found to be 5.996, which compared to the accepted value of 1.49 has a percent of error of 302.42%.

own words -7

  • fit? -3