EE Ph.D. Oral Examination: Jae-Woong Jeong, Feb. 27 at 3:00 pm, CIS-X Auditorium

Stanford University Ph.D. Oral Examination – Department of Electrical Engineering

 

Title:

Design of Optical Microsystems:

Applications in Biomedical Imaging and Optical Communication

 

Speaker: Jae-Woong Jeong

Advisor: Professor Olav Solgaard

 

Date: Monday, February 27, 2012

Time: 3:00 pm (refreshments at 2:45 pm)

Location: Allen-X Auditorium (formerly CIS-X Auditorium) - Room 101

 

Abstract:

 

Scaling of optical systems can open up new opportunities for various applications by enabling what would not be possible on a larger scale. Such miniaturized optical systems can be achieved through optical MEMS (Micro-electro-mechanical systems) technology. This technology not only enables optical devices with high performance and high functionality, but also allows miniaturization, integration, and batch fabrication of optical systems, making them portable, reliable, and cost-effective. In this talk, I will present two novel optical microsystems for applications in biomedical imaging and optical communication.

 

    In the first part of my talk, I will introduce the 3-D MEMS scanning system for a miniature dual-axis confocal (DAC) microendoscope, which is an emerging biomedical imaging modality with high resolution, good tissue penetration, large field of view, and the ability to provide both reflectance and fluorescence contrast images. A pair of MEMS scanners (2-D lateral and 1-D vertical MEMS scanners) that are designed to achieve 3-D scanning in an endoscope-compatible imaging probe will be presented. In addition, front-side processing of the scanners that enables not only simple and cost-effective fabrication but also compact and robust structures will be described. Co-operation of a 2-D lateral scanner and a 1-D vertical scanner enables fast 3-D microscopy over a volume that measures 340μm X 236μm X 286μm. I will describe the principle of the all-MEMS-based 3-D scanning DAC microscopy that gives the functionality of OCT to a confocal microscope by producing real-time imaging along the axial direction of the microscope.

    In the second part of my talk, I will describe the design, fabrication, and characterization of a multi-functional tunable optical filter, which is a key element for dynamic wavelength provisioning in reconfigurable optical networks and communication systems. This filter can control both the center wavelength and the passband independently and continuously, using a MEMS spatial light modulator (SLM) that is implemented with gold-coated mirrors microassembled on a MEMS platform. The design of SLM with large displacement bi-directional combdrive actuators will be demonstrated. Also, MEMS platform technology that enables a compact chip size with large apertures and high-quality optical mirrors will be presented. To verify the performance of the filter, it has been tested as an amplified spontaneous emission (ASE) noise rejection filter in a 10Gb/s optical communication system. I will discuss the filtering performance in the optical system in terms of bit error rate improvement.