EEL 4440 Optical Engineering
Spring 2001
Homework set 1
Due Thursday, January 18, 2:30 p.m.
Start each question on a fresh page. Staple all your answers together in order. Write your name on
each sheet of paper you turn in. Clearly show your working, explaining what you are doing along the
way. READ the question - if a sketch is asked for, make sure (a) that it is clearly drawn (b) that it is
clearly labeled.
1. Light is to be coupled into a glass fiber of index n = 1.45 as shown below.
Once the light is in the fiber it must be trapped in the fiber by total internal
reflection What is the maximum angle ?i at which a ray can enter the end of the
fiber and still be trapped by total internal reflection?
2. A fish is one meter below the surface of a pond. If you are looking more or
less vertically down at the fish, how deep does it appear to you to be? (The
refractive index of water is 1.33.)
3. An object is distance s from a spherical mirror of radius of curvature R. Find
an expression for the magnification, m, in terms of R and s only. Plot or sketch
a graph of m versus s for R = 20 cm, and for R= -20 cm.
For the following problems, you may wish to use the virtual optics workbench on the
web to help you visualize and check your answers. However, you still need to make
accurate drawings and perform precise calculations.
?i
air
n = 1.45
