EE737 Homepage

Department of Electrical Engineering
The Ohio State University
Course Syllabus
EE737
Photonics Laboratory
Winter 2003

Prerequisites:	312, and prerequisite or concurrent 432; or grad standing.
Learning Goals:	Students will learn about modern photonic devices, measurements, and optical approaches to solving engineering problems. You will learn optical laboratory techniques, measurement strategies, and safety precautions. A big part of this course is learning to become an independent scientist, which means using resources outside of the textbook. It also means you interpret your own data, and identify and solve measurement problems. It also means writing effective, professional reports and keeping a professional quality laboratory notebook.
Description:	Students will do four experiments in modern photonics from among: fiber optic communications, optical sensing, acousto-optic modulation, laser diode physics, liquid crystals, and solar cells. In addition, you will be learning about the physics, principles, and applications of these technologies from a set of notes, supplemented by the library. The supplementary lecture portion covers more topics in modern optics and measurements not covered by the lab. This course is designed to teach lifelong learning and technical writing in addition to optics.
Text:	Required:	Photonics Lab Manual available from COP-EZ
	Recommended:	Fundamentals of Photonics, B.A.A. Saleh, M. Teich, John Wiley and Sons, 1991, ISBN 0-471-83965-5 Available on-line through the OSU libraries at http://www.netLibrary.com/ebook_info.asp?product_id=26193). To read this book on-line you will need to download and install the DjVu plug-in (avialable at that page). A copy is also available on closed reserve at the Science and Engineering Library (http://www.lib.ohio-state.edu/phyweb/).
Policy on Late Assignments:	No late work will be accepted without prior arrangement. Late work (with arrangements) will be docked 10% per day.
Missed labs:	It will not be possible for you to make up any missed labs.
Safety:	You are expected to know what safety precautions are required for any lasers or other equipment that you are using, and to observe those precautions. Failure to observe safety practices will result in your being bawled out, despised, and you will lose points in your grade from the lab practice/procedure contribution.

**Grading**
10%	Safety Quiz	The 10% lab practice and procedures will be evaluated by the instructors questioning individual students on the equipment, the setup, etc, during the lab session. NOTE that this class therefore has a sizable subjective component to your grade.
10%	Lab practice and procedures (instructor’s judgment)
15%	Two quizzes on lecture material
35%	Written Laboratory reports
10%	Laboratory notebook
20%	Homework (5 % problems and 15% library problems)

**Due Dates**
Lab 1	Safety Demonstrations in Lab
Lab 2	Safety Homework, First Problem set
Lab 3	First set of Library Problems
Lab 4	Second Problem Set, First Lab Report
Lab 5	Second set of Library Problems
Lab 6	Third Problem Set, Second Lab Report
Lab 7	Third set of Library Problems
Lab 8	Fourth Problem Set, Third Lab Report
Lab 9	Fourth set of Library Problems
Monday of Finals Week	Fourth Lab Report
Assignments are due at the beginning of each lab session.

Format

Each student will have the opportunity to do four of the six experiments. You will submit a preference sheet prioritizing the experiments (first choice, second choice, etc), and the instructor will assign the experiments and lab teams. Please understand that it may not be possible to do your top four choices because of scheduling conflicts, but we will try to do the best we can. The lab teams will in general change from experiment to experiment.
Before you will be permitted to do any experiment, you will read the chapter on that technology and hand in the accompanying homework assignments. For example, if you will be doing “Laser Diode Physics” during the next two weeks, you will have to first read and understand that chapter in the notes.
The homework has been specifically designed to require you to go to the library. We recognize that this requires a lot of time, as will the homeworks, lab reports, etc. That is why the course is worth 4 credits instead of the usual 2. This course should require 33% more time and effort than your standard 3-credit course. This homework format will teach you valuable skills.
There are four two-week cycles of experiment during the quarter. The first cycle starts the second lab session (the first lab session is devoted to preparation and safety). The schedule above shows due dates for various assignments:

**Description of Experiments:**
1)	Digital Fiber Optic Communication Link:	Students construct an operating digital fiber link and examine the effect of power loss on the bit-error-rate (BER). Students build a link that includes a coupling of two bare fibers face-to-face. You will investigate how loss affects BER by artificially introducing longitudinal, lateral, and angular offsets in the coupling. Students will: learn how to cleave fibers and how to couple light into fibers experience firsthand the importance of alignment losses in fiber-to-fiber coupling, and the relative impacts of the three different types of fiber misalignment learn how to perform BER measurements, how to relate BER to signal-to-noise, and observe firsthand how loss in power degrades BER.
2)	Optical Sensing:	Students will study various configurations of fiber sensors (amplitude vs. phase, extrinsic vs. intrinsic, reflective). They will learn about transduction mechanisms, including bending losses, photoelastic effect, external/frustrated reflection, controlled refractions, etc. Students will choose a sensing problem to solve (force, displacement, vibration, roommate detector, liquid level, rotation, etc.) and design and build an optical (not necessarily fiber) sensor. Students will: learn to cleave fiber and launch light into fibers (if fibers are involved) learn about modes in fibers, and their effect on lead noise study sensitivity, resolution, dynamic range, and linearity as transducer issues design, build and characterize a sensor for the measurand of their choice learn about coupling issues and power budgets
3)	Laser Diode Physics:	Students will study threshold, gain, and Fabry-Perot cavities using semiconductor lasers. They will examine the spectrum of a laser below and above threshold, calculate and then measure longitudinal mode spacing, examine the change in threshold and power-current slope as a function of temperature, and observe mode-hopping. In particular, the students: learn about handling laser diodes (static sensitivity and supply requirements) learn how to measure and interpret power-current curves learn how to use a monochromator and the physics behind the instrument investigate the differences between spontaneous and stimulated emission see how modes are selected under the gain curve by examining mode-hopping
4)	Photovoltaic Devices:	Students investigate and measure the photovoltaic properties of both semicrystalline Si and amorphous Si terrestrial solar cells. They will determine the fundamental differences between these two types of semiconductors. Students will construct a paper design of a photovoltaic power system, optimized for an application supplied by the instructor. From this, students will develop an appreciation for performance-cost tradeoffs in engineering design. In particular, students will: learn how to measure lighted I-V characteristics with a curve tracer calculate cell efficiency and measure and interpret spectral response examine effects of the different bandgaps and diffusion lengths in semicrystalline vs. amorphous materials on device performance study effects of varying solar flux (intensity) on cell performance design a photovoltaic power system based on your individual measurements of cell performance for each type of cell
5)	Acousto- Optics:	Students perform spatial light modulation using acousto-optic devices. You learn the physics of the acousto-optic effect, and the differences between Raman-Nath diffraction and Bragg diffraction. They will learn about gratings, and the Doppler shift of the light frequency. Specific learning goals are: investigate diffraction efficiency into various order of diffraction verify the relationship between photon and phonon momentum by measuring sensitivity of diffraction to angle of incidence spatially scan a laser beam by varying the frequency of the acousto-optic signal amplitude modulate a laser beam by varying the acoustic power construct an all-optical switch
6)	Liquid Crystals:	Students will study some of the issues in flat panel display technology (contrast, speed, viewing angle, and character configurations such as seven-segment). As an example technology, they will learn the physics of liquid crystals. Students will fabricate three liquid crystal cells: parallel nematic, twisted-nematic, and Smectic-C. These are simple to make using indium-tin-oxide coated glass slides and thin sheets of Mylar (for spacer). These unsealed devices are stable for approximately a day. Students will: construct actual liquid crystal devices measure contrast ratio, polarization, and speed of response as a function of voltage and viewing angle. investigate how uniformity of thickness affects display appearance and operation compare your devices to a commercial display