AOD를 채용한 디지털 홀로그래픽 광 메모리 시스템에 관한 연구 :

다국어 초록 (Multilingual Abstract)

'Rapid growth of computer communication service and internet users is demanding the computer memories which can deal with data in close to real time. Because data of computer communication and internet is large image data. Therefore, the next-generation computer memory that can perform fast storage fast storage and retrieval of large image data is required. As one of the promising candidates, the research is progressing actively on optical memory system using holography technique. High data density storage system can be realized by adopting three-dimensional such as photorefractive crystal as a recoding medium and various multiplexing(angular/spatial/phase code/wavelength) technique. Also this system has rapid access time by parallelism of laser beam. Therefore, this system is profitable for storage and retrieval of large image data(still image or moving image). Especially, digital holographic recoding and retrieval technique improve quality of retrieved image. Also, it has potential as memory that overcome I/O bottleneck of digital computer.
In this paper, angular multiplexing technique was described. Angular multiplexing is divided mechanical method and electrical method. Mechanical method using step motor is to prone system design. But it has not rapid access time and accurate repeatable setting
of reference beam. Electrical method using AOD offers rapid access time and accurate repeatable setting of reference beam.
Therefore, in this paper, digital holographic optical memory system was realized by recording and retrieval multiple binary encoded by Reed-Solomon code images in photorefractive crystal utilizing angurlar multiplexing technique using step motor and
AOD. Also, compression algorithm was adopted. Therefore, capability of digital holographic optical memory of high data density was proposed.

목차 (Table of Contents)

• 1장 서론 = 1
• 2장 디지털 홀로그래픽 광메모리 시스템 = 5
• 2.1 평면 및 볼륨 홀로그램 = 5
• 2.2 광굴절 효과 (Phototefractive Effect) = 6
• 2.3 디지털 홀로그래픽 광메모리 시스템 = 9
• 2.4 디지털 홀로그래픽 광메모리 시스템의 각다중화 방법 = 13
• 2.4.1 스텝 모터를 이용한 각다중화 = 14
• 2.4.2 음향-광학 편향기(AOD : Acousto Optic Deflector)를 이용한 각다중화 = 15
• 3장 디지털 홀로그래픽 광메모리 시스템을 위한 코딩 기법 = 19
• 3.1 Reed-Solomon 코딩기법 = 19
• 3.1.1 오류정정 부호화의 배경 = 19
• 3.1.2 오류정정 부호화의 응용 = 19
• 3.1.3 Reed Solomon코드의 부호화 및 복호화 = 21
• 3.2 channel coding 기법 = 29
• 3.2.1 binary threshold encoding = 29
• 3.2.2 binary differential encoding = 29
• 4장 고밀도 디지털 홀로그래픽 광메모리 시스템을 위한 압축기술 = 31
• 4.1 JPEG (Joint Photographic Expert Group)의 개요 = 31
• 4.2 JPEG 알고리즘 = 31
• 5장 실험 결과 및 고찰 = 37
• 5.1 스텝 모터를 이용한 각다중화 실험 = 37
• 5.2 AOD에 의한 각다중화 실험 = 45
• 5.3 압축을 이용한 고밀도 광메모리 시스템 실험 = 54
• 6장 결론 = 60
• 참고문헌 = 62