for pictures of the lab click here
Summary:
There are two types of fiber optic sensors, intensity sensors and phase sensors, where intensity sensors use multimode fibers and phase sensors use single-mode fibers. Intensity sensors can be further divided into a subset of sensors classified as hybrid and internal effect sensors. Hybrid sensors use a device called a transducer to channel light down a given path to a remote sensor at the end of the fiber. Internal effect sensors use the fiber itself as the transducer. The type of hybrid sensor that will be constructed during the spring semester of 1997 at Bucknell University will be a pressure sensor. This pressure sensor will be constructed so that the power transmitted can be observed as a function of applied pressure. The transducer will help to make this type of measurement possible because the transducer takes on physical parameter and converts it into an easier physical parameter that can be measured.
Objectives:
The main objective will be to successfully construct the pressure sensor so that the power transmitted can be observed as a function of applied pressure. To accomplish this task various instruments and practice coupling a HeNe laser into multimode fiber will be needed. Coupling a laser into multimode fiber was one of the tasks that was done in my optoelectronics course last spring and this required a lot of patience and was not in any way easy. However, the various precision optical mounts and translational stages will help aid in the successful completion of coupling the HeNe into the fiber with their eminently fine adjustments. Another important aspect of coupling the HeNe into the fiber will be the vibration isolation that is given by the optical table or breadboard. The pressure sensor that will be constructed during this semester is outlined in Experiment #9 of Newport's Projects in Fiber Optics. Each step is clearly outlined and what should be observed is clearly stated. However, there are not any equations that will correlated the power transmitted as a function of applied pressure. Therefore these equations must be derived. It is my hope that this sensor will be successfully completed somewhere around March 14 and no later than the first week in April. During construction of this sensor, a lab handout will also be developed that resemble those given in EE341. It is important to note that this lab handout will be developed for people who have had optoelectronics and for those who have not. The lab handout will include some background information on fiber optic sensors, a step-by-step set-up procedure that help in learning how to couple a laser into fiber, some lab questions that should be answered in the lab report submitted by the students, and a survey of the overall lab to be completed by the students at the completion of the lab exercise. If the feedback is positive for this lab exercise, with the approval of Dr. Lord, it will become a part of the optoelectronics curriculum.
Plan of Action
The progressive stages for this project will tentatively be to:
Equipment:
The components that are required for the completion of this pressure sensor can be found in Appendix 1: Parts List, which was provided by the Newport Corporation. It should be noted that all of the equipment needed is already available in Dr. Lord's optoelectronics laboratory. In addition to what was listed, a numerous amount of optical mounts and translation stages will also be needed because it is virtually impossible to set up this pressure sensor that way it is pictured in the lab manual without them. There are just too many fine adjustments that are necessary to receive maximum power through a fiber optic cable. It is also worth noting that Ryan Sherry will also be conducting similar experiments which means it will become necessary to implement two or more setups. I agree with Ryan about the approximate expenditure of $2000, since some translation stages are quite expensive. Since Dr. Lord has indicated that she is willing to supply a reasonable amount of funding from the grants available to her for additional equipment, I do not view this as a problem.
Closing:
The feasibility of this senior design project is based on the description of fiber optic sensors and the step-by-step procedure outlined in Experiment #9: Multimode Intensity Sensors in "PROJECTS IN FIBER OPTICS: Applications Handbook" provided by the Newport Corporation. My experience working with Dr. Lord in optoelectronics class and lab and also my lecture notes will prove helpful in successfully completing this project.
last updated 7/9/97