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BARIS BICEN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ph.D. Candidate, Research Assistant
Advisor: Dr. F. Levent Degertekin
Work Phone: (404) 385-2051
Work Fax: (404) 385-2011
baris@gatech.edu

 

Education:

 

  • Ph.D. in Mechanical Engineering, August 2004-present, Georgia Inst. of Tech.
  • M.S. in Mechanical Engineering, 2006, Georgia Inst. of Tech.
  • B.S. in Mechanical Engineering, 2004, Middle East Technical University, Turkey

 

Research Experience:

  • Summer 2003, Intern, Mechanic Prototype Workshop, Aselsan, Turkey
  • Summer 2002, Intern, Microwave and System Tech Division, Aselsan, Turkey

 

Research Projects:

 Micromachined Diffraction Based Optical Microphones and Intensity probes with Electrostatic Force Feedback

 

Microphones are widely used in many applications like cellular phones, hearing aids and acoustic measurement devices. As the size of the microphone diaphragms reduces with the use of microelectromechanical systems (MEMS) technology, traditional capacitive sensing methods used in miniature microphones imposes key limitations on microphone performance. The use of diffraction-based optical detection method alleviates these limitations by providing high displacement detection sensitivity nearly independent of the size and the capacitance of the microphone. This enables novel backplate and diaphragm designs to obtain low noise performance with broad bandwidth. In this project, optical detection method is used with micromachined biomimetic gradient and omnidirectional microphone structures. In these micromachined microphones, the integrated electrostatic port of the sensor is uncoupled from the integrated optical sensing making it available for sensitivity tuning, self characterization, and active control to adjust the device dynamics. The proposed research explores the feasibility of low noise, high bandwidth and high fidelity optical microphones with force feedback, and intensity probes based on these microphones. Initial implementation of force feedback method shows that it is possible to alter the dynamics of the microphones in a desirable manner while achieving directionality and extremely low noise levels. Small size, broad band intensity probes using biomimetic gradient microphones and omnidirectional microphones phase matched with force feedback are investigated. These devices would enable identification and characterization of complex acoustic fields generated by small sources.

 

Characterization of the micromachined broadband transducers with integrated diffraction-based optical displacement detection:

 

For most of the applications, high sensitivity to size ratio is the most critical factor for microphones and accelerometers. With the advancing microelectromechanical systems (MEMS) technology, it is possible to fabricate small-sized micromachined microphones. Also with that technology, fabricating of the identical microphones on the same die is possible. This enables to make small sized microphone arrays with closely matched microphone elements. However, the capacitive displacement method that is used widely in microphones causes problems with the decreasing size of the microphone. With the size reduction, parasitic capacitances become more dominant. Also to decrease the squeeze film damping effect in capacitive microphones, the gap between the diaphragm and the electrode should be larger. However, if the gap is larger, the sensitivity is lower. The other solution for the squeeze film damping effect is to perforate the diaphragm for air flow. The perforating the diaphragm decreases the effective area and the active capacitance. These conflicts and tradeoffs cause the need of alternative sensing techniques instead of capacitive detection. Optical detection method is an alternate method for capacitive detection in microphones. Diffraction based optical displacement detection method has shown advantages in terms of sensitivity and dynamic range.

 

Integrated Multi-Signal Adaptive Microphone

 

The goal of the project is to develop the technology for signal processing to extract and separate acoustic sources and to integrate this technology with a low noise, optical detection microphone. The approach applies the gradient flow (GF) and independent component analysis (ICA) for signal separation. The main advantage of the optical microphones is the high sensitivity to size ratio. This advantage is also coupled with the ability to fabricate individual microphone elements with precisely matched properties on the same silicon chip. These features enable the approach of making high fidelity miniature microphone arrays. Employing developed signal processing algorithms to these miniature microphone arrays is the ultimate goal for sound source localization and separation in the audio frequency range.

 

Journal Publications:

Hall, N.A.   Okandan, M.   Littrell, R.   Bicen, B.   Degertekin, F.L., “Simulation of Thin-Film Damping and Thermal Mechanical Noise Spectra for Advanced Micromachined Microphone Structures,” Journal of Microelectromechanical Systems,  Volume 17, Issue 3, pp. 688-697, June 2008.

 

Hall, N.A.   Okandan, M.   Littrell, R.   Serkland, D.K.   Keeler, G.A.   Peterson, K.   Bicen, B.   Garcia, C.T.   Degertekin, F.L., “Micromachined Accelerometers With Optical Interferometric Read-Out and Integrated Electrostatic Actuation,” Journal of Microelectromechanical Systems,
Volume 17, Issue 1, pp 37-44, February 2008.

 

Neal A. Hall, Murat Okandan, Robert Littrell, Baris Bicen and F. Levent Degertekin, “Micromachined optical microphone structures with low thermal-mechanical noise levels”, The Journal of the Acoustical Society of America, Volume 122, Issue 4, pp. 2031-2037, October 2007.

 

N.A. Hall, B. Bicen, W. Lee, K. Jeelani, S. Qureshi, M. Okandan, and F.L. Degertekin, “Micromachined Microphones with Diffraction-Based Optical Displacement Detection,” The Journal of the Acoustical Society of America, Volume 118, Issue 5, pp. 3000-3009, November 2005.  

 

Conference Papers/Presentations:

Baris Bicen, Caesar Garcia, N.A. Hall, M. Okandan, Weili Cui, Quang Su, R. Miles, F.L. Degertekin, “Diffraction Based Optical MEMS Microphones and Accelerometers with active Electrostatic Force Feedback”, 155th Meeting of the Acoustical Society of America, Paris, France, 28 June—4 July 2008.

 

Okandan, M.   Hall, N.   Bicen, B.   Garcia, C.   Degertekin, F.L., “Optical Microphone Structures Fabricated for Broad Bandwidth and Low Noise”, Sensors, 2007 IEEE, pp. 1472-1475, October 2007.

 

F. Levent Degertekin, Neal A. Hall, Baris Bicen, “Micromachined microphones with diffraction-based optical interferometric readout,” 152nd Meeting (4th joint meeting of the Acoustical Society of America and the Acoustical Society of Japan), Honolulu, Hawaii, 28 November--2 December 2006.

 

Murat Okandan, Neal A. Hall, Robert Littrell, Baris Bicen and F. L. Degertekin, “The surface and bulk microfabrication of optical seismometers and vibrometers using Sandia National Laboratories' silicon micromachining technology,” The Journal of the Acoustical Society of America, Volume 120, Issue 5, pp. 3329-3330, November 2006.

 

R. N. Miles, W. Cui, Q. Su, R. Wu, L. Tan, Y. Liu, S. A. Jones, V. Mohnankrishnaswami, T. Strait, W. Butler, D. DiBernardo, F. L. Degertekin, B Bicen, W. Lee, K Jeelani,   “Development of novel biologically inspired directional microphones,” 152nd Meeting (4th joint meeting of the Acoustical Society of America and the Acoustical Society of Japan), Honolulu, Hawaii, 28 November--2 December 2006.

 

Weili Cui, Baris Bicen, Neal Hall, Stephen A. Jones, F. Levent Degertekin and Ronald N. Miles, “Optical Sensing In A Directional MEMS Microphone Inspired By The Ears Of The Parasitoid Fly, Ormia Ochracea,” IEEE International Conference on Micro Electro Mechanical Systems (MEMS 2006) Istanbul,Turkey,2006.