ECEN 4616/5616
“Optoelectronic System Design”
MWF 1:00 -> 1:50, ECCR 155
Instructor:
Bob Cormack
Bob.Cormack@Colorado.edu
(Currently not working – for now, use :)
bcormack@indra.net
(720) 470-1836 (cell)
OFFICE: ECEE
OFFICE HOURS: TBD (class discussion)
TEXTBOOK (?? Not in schedule ??)
Suggest:
“Geometrical Optics and Optical Design”
Mouroulis & Macdonald
Also suggest:
“Fundamentals of Geometrical Optics”
SPIE publication
$40.00 hardcopy, or (recommended) app on iTunes for $7.00
“OPTICS” (Scharm’s Outline Series)
About $12-$14, hardback or Kindle at Amazon
I will try to have relatively comprehensive notes to hand out, but it is
hard to replace a text. Notes will also be available on-line, whenever
IT gets my email and web services working.
Legal Fine Print
(1) If you qualify for accommodations because of a disability, please submit to your professor a
letter from Disability Services in a timely manner (for exam accommodations provide your letter at
least one week prior to the exam) so that your needs can be addressed. Disability Services
determines accommodations based on documented disabilities. Contact Disability Services at
303-492-8671 or by e-mail at dsinfo@colorado.edu.
If you have a temporary medical condition or injury, see Temporary Injuries under Quick Links at
Disability Services website and discuss your needs with your professor.
(2) Campus policy regarding religious observances requires that faculty make every effort to deal
reasonably and fairly with all students who, because of religious obligations, have conflicts with
scheduled exams, assignments or required attendance. In this class, {{insert your procedures
here}}
See full details at http://www.colorado.edu/policies/fac_relig.html
(3) Students and faculty each have responsibility for maintaining an appropriate learning
environment. Those who fail to adhere to such behavioral standards may be subject to discipline.
Professional courtesy and sensitivity are especially important with respect to individuals and
topics dealing with differences of race, color, culture, religion, creed, politics, veteran’s status,
sexual orientation, gender, gender identity and gender expression, age, disability, and
nationalities. Class rosters are provided to the instructor with the student's legal name. I will
gladly honor your request to address you by an alternate name or gender pronoun. Please advise
me of this preference early in the semester so that I may make appropriate changes to my
records. See policies at
http://www.colorado.edu/policies/classbehavior.html and at
http://www.colorado.edu/studentaffairs/judicialaffairs/code.html#student_code
My Teaching Philosophy
1. I want everyone to understand the material:
a. If you understand the material presented in class, you can
get an “A” on the tests – I don’t expect you to derive
something new during a test.
b. Doing the homework problems is integral to understanding –
learning without practice is ephemeral.
2. Ask questions when you have them:
a. Don’t get left behind.
b. There are no dumb questions – questions aren’t graded.
3. There will be occasional derivations from basic theory (e.g.,
Maxwell’s equations):
a. You will be expected to know what the results mean for an
engineer and designer.
b. You will not be expected to reproduce derivations without a
reference.
Grading
1. Homework:
a. Every two weeks, with some exceptions.
b. Knowledge/calculation questions have correct answers.
c. Design problems have no unique correct answer.
2. One Mid Term exam, covering the first half of the course and a
final exam mostly covering the second half of the course, with
some questions from the first half.
3. DESIGN PROJECT:
a. Initial “White Paper” proposals (1-2 pages) due by midcourse. (A list of possible projects will be available.)
b. Various milestones, reflecting the design stages
presented in the course.
c. Completed project (essentially, the milestone reports
tacked together, if you’ve done it right) and a short (10
minute) oral presentation to the class.
4. Homework, Exams, and Design Project all count 25% each.
Late work is grade reduced 5%/day.
Major Goals of the Class:
1. Acquire the knowledge of how one goes about specifying and
designing optical systems including sources and detectors.
While a single course won’t give you much practice at the actual
skill involved, you can learn the methodology – given a design
problem, you will know how to proceed.
2. Become acquainted with a variety of optoelectronic systems,
including classical systems and systems involved in current
research – see how diverse problems have been solved:
a. Imaging systems: Cameras, microscopes, telescopes, etc.
 The differences between systems designed for
electronic output (imaging detectors) and output to the
human eye.
b. Communications Systems: How light is used to transport
information and what the design problems are.
c. Computational Optics: Use of computer processing to
supplement (or replace) some of the tasks of the optics.
Leading-edge research at CU on various aspects of this:
 “Error encoding” optical systems to distinguish signal
(light from the object) from noise (everything else,
including stray light and electronic noise).
 Extended Depth of Field (EDOF) optical systems
 3D information (z-axis) from images, at extremely high
resolution.
Aside: The Human Visual System (HVS) IS a Computational
Optics system. For example, though wearable eyeglasses were
invented over 700 years ago (and hand-held vision aids hundreds
of years earlier), there are still unsolved research problems with
them:
 Multi-focal eyeglasses (bifocals and blended bifocals)
do not yet exploit the very high processing power of
the retina-optic nerve-brain system.
 CU research on multi-focal contact lenses show that
the HVS can easily learn to perform significant nonlinear filtering operations and can operate as an
essential element in a total visual solution.
 Myopia (near-sightedness) progression is an epidemic
in developed countries. Current research points to a
cause that could be removed with innovations in lens
fabrication.
3. Simplified Optical Propagation Methods: The basic calculation
in optical design is the simulation of light propagation through an
optical system. To do this exactly using EM waves is a difficult,
costly (no inexpensive programs available) and time-consuming
task. Geometrical optics is (among other things) the study of
approximate methods of accomplishing this simulation. The
techniques include:
a. Rays: Rays are defined as lines perpendicular to
wavefronts. They don’t actually exist, but are a useful fiction
for propagating wave structures through systems that are
much larger than the wavelength. There are three ways to
propagate rays:
 ‘Graphical’ rays: These can be traced ‘by hand’
without any calculations. This is useful for blocking out
a starting solution.
 Paraxial ray-trace formulas: These are the linear
formulas describing ray propagation through paraxial
optics.
 Snell’s Law: The actual deviation of a ray at a real
interface, derived from Maxwell’s equations.
b. Paraxial Optics: (So named because ordinary lenses are
nearly linear for light close to the optical axis – ‘paraxial’.)
This is the theory of idealized, perfectly linear ‘lenses’. While
only a few exact problems in optics can be inverted, many
more can in this approximation. Thus it is very useful for
generating starting solutions for many problems.
c. Gaussian Optics: This is the extension of paraxial optics to
lenses of finite thickness, which are still ideally linear. This is
a useful way to simulate the inclusion of pre-built lens
systems (such as camera lenses) into a larger system.
4. Refinement of starting optical systems: Once a potential
system has been identified it is expanded to allow correction of
aberrations, which are deviations of real systems from the ideal
models above. A number of aberrations can be corrected at the
Paraxial level, including:
a. Chromatic aberration: The differing power of a lens for
differing wavelengths due to the index of refraction being a
function of wavelength.
b. Field curvature: Petzval’s Theorem is an interesting
paraxial theorem which shows that a combination of lenses
cannot image an object plane to an image plane unless it
contains an equal total power of positive and negative
surfaces.
5. Heuristic search for optimum real solutions: This used to be
the extremely tedious part of optical engineering – tracing real rays
using trig tables. Older optical books (often written by retired old
optical designers) may spend much effort on schemes to extract
the maximum amount of information from each ray traced.
Today, this is done by optical design programs (such as Zemax).
My current laptop will trace ~30,000,000 rays/second through a
typical optical system: I don’t really care if each ray doesn’t
achieve the maximum amount of information on adjusting the
system.
However; If the starting design has not been properly defined, it
may not have the potential to correct the various aberrations and
the “automatic design program” will fail to find a reasonable
solution.
I am working on getting a class license for Zemax, so everyone
can get some experience using this program. Modern optical
design is not done entirely by such programs, but it is also not
done without them.
Notes on Optical Design Methodology:
Optical design falls into the class of problems that can be
calculated in the forward direction:
Given an optical system and an input, we can calculate the output.
but cannot be easily (except for a few simple problems) inverted:
Given an optical input and a desired output, we cannot (in general)
derive the optical system.
This is similar to the problem of electronics design, and is attacked in
a similar way – the “Cookbook” method.
 Most optical design problems involve variations of a set of
known tasks:
o Imaging illuminated objects
o Collecting and concentrating light
o Creating patterns of light (or shadow)
o Coupling light into and out of structures, such as glass
fibers.
Hence, the first step, when faced with a design problem, is to
research how others have solved similar problems.
Individual active electronics components (such as transistors) are
plagued by significant non-linearities. In electronics design, a major
revolution has been the development of composite design
components – operational amplifiers – which simulate a linear active
element. In optics the analgous elements would be Pre-existing
Camera Lenses and Designs.
There are a great many already designed and fabricated lenses for
digital cameras which span a huge range of parameters and uses:
These lenses are designed to be essentially linear – that is, the
output image is a faithful representation, on a plane surface, of the
input source object, at another plane ahead of the lens.
This level of performance is not possible with a single element, and is
difficult to achieve with single lenses from catalogs. Generally, a
good imaging lens system requires custom ground lenses and
custom fabricated mounts.
For prototyping and other low-volume uses, using (if possible) preexisting digital camera lenses can be the fastest and most
economical option.
Similar collections of pre-designed optics are available for microscopy
and optical networking.
Sources for these lenses are:
 Industry catalogs (for built lenses)
 Patent databases (for designs)
 Special databases, such as Zemax’s Zebase.
 General Internet searches