Development of an all-fiber homodyne quadrature laser interferometer for integration into a compact thermal actuator

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Hastings, D. J. (2021). Development of an all-fiber homodyne quadrature laser interferometer for integration into a compact thermal actuator. Unc Charlotte Electronic Theses And Dissertations.
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Abstract

D.J. HASTINGS. Development of an all-fiber homodyne quadrature laser interferometer for integration into a compact thermal actuator(Under the direction of DR. STUART T. SMITH)This thesis presents the development of an all-fiber homodyne quadrature laser interferometer (HQLI) for integration into a newly designed, compact thermal actuator capable of driving loads up to 1000 N in high temperature environments. The source of the HQLI consists of a commercially available, 635 nm, fiber coupled, single-mode laser diode. Major components of the optical system comprise a two input by two output fiber splitter, two dielectric mirrors, and a photodetector. The two output arms of the HQLI are called the device-under-test (DUT) arm and the Modulation (MOD) arm. The DUT arm will ultimately be integrated into the thermal actuator. The MOD arm is the controlling arm for the quadrature detection. These two arms are the only locations where light from inside the fiber is exposed to the ambient environment. The MOD arm uses a dielectric mirror opposite the standard, single mode FC fiber ferrule. The MOD arm has accommodations for feedback control via a capacitance gage to reduce drift in the modulation displacement of the modulation mirror. The DUT arm was tested with the same single mode fiber type and dielectric mirror as the MOD arm. Future work to install the DUT arm into the thermal actuator will be completed using the same flat polish for the end-face of the fiber. The output arm of the HQLI is called the photodetector (PD) arm and is connected to a commercially available photodetector and photodetector amplifier. The output of the photodetector amplifier is fed to signal conditioning stages to increase the contrast of the fringes. A lock-in amplifier has been employed to determine the first (1f) and second (2f) frequency harmonics of the fringes that form the basis of quadrature detection. The HQLI has been tested to maintain fringe stability over a time period of thirty minutes, a displacement resolution of 30 nm, and an operating range of 3.0 mm at standard laboratory conditions. The novel feature of this thesis is the design of a thermal actuator with methods for implementation and control, and materials of construction that can withstand harsh operating environments, mainly temperatures higher than a standard laboratory environment. The thermal actuator has been tested with an applied axial load of 1000 N for an extended period of time without mechanical failure. Open loop time responses have been measured for varying pulse width modulations of a 120 W power supply to a high power induction heater.

Details
Author

Hastings, DJ

Title

Development of an all-fiber homodyne quadrature laser interferometer for integration into a compact thermal actuator

Physical Description

1 online resource (168 pages) : PDF

Date

2021

Degree Granting Institution

University of North Carolina at Charlotte

Abstract

D.J. HASTINGS. Development of an all-fiber homodyne quadrature laser interferometer for integration into a compact thermal actuator(Under the direction of DR. STUART T. SMITH)This thesis presents the development of an all-fiber homodyne quadrature laser interferometer (HQLI) for integration into a newly designed, compact thermal actuator capable of driving loads up to 1000 N in high temperature environments. The source of the HQLI consists of a commercially available, 635 nm, fiber coupled, single-mode laser diode. Major components of the optical system comprise a two input by two output fiber splitter, two dielectric mirrors, and a photodetector. The two output arms of the HQLI are called the device-under-test (DUT) arm and the Modulation (MOD) arm. The DUT arm will ultimately be integrated into the thermal actuator. The MOD arm is the controlling arm for the quadrature detection. These two arms are the only locations where light from inside the fiber is exposed to the ambient environment. The MOD arm uses a dielectric mirror opposite the standard, single mode FC fiber ferrule. The MOD arm has accommodations for feedback control via a capacitance gage to reduce drift in the modulation displacement of the modulation mirror. The DUT arm was tested with the same single mode fiber type and dielectric mirror as the MOD arm. Future work to install the DUT arm into the thermal actuator will be completed using the same flat polish for the end-face of the fiber. The output arm of the HQLI is called the photodetector (PD) arm and is connected to a commercially available photodetector and photodetector amplifier. The output of the photodetector amplifier is fed to signal conditioning stages to increase the contrast of the fringes. A lock-in amplifier has been employed to determine the first (1f) and second (2f) frequency harmonics of the fringes that form the basis of quadrature detection. The HQLI has been tested to maintain fringe stability over a time period of thirty minutes, a displacement resolution of 30 nm, and an operating range of 3.0 mm at standard laboratory conditions. The novel feature of this thesis is the design of a thermal actuator with methods for implementation and control, and materials of construction that can withstand harsh operating environments, mainly temperatures higher than a standard laboratory environment. The thermal actuator has been tested with an applied axial load of 1000 N for an extended period of time without mechanical failure. Open loop time responses have been measured for varying pulse width modulations of a 120 W power supply to a high power induction heater.

Genre

masters theses

Subjects--Topics

Engineering

Degree

M.S.

Subject Area

Mechanical Engineering

Advisor(s)

Smith, Stuart

Committee Members

Keanini, Russ
Miller, Jimmie
Tarbutton, Joshua

Degree Note

Thesis (M.S.)--University of North Carolina at Charlotte, 2021.

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Rights Holder Information

Copyright is held by the author unless otherwise indicated.

Identifier

Hastings_uncc_0694N_12879

Permalink

http://hdl.handle.net/20.500.13093/etd:2994