• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.11
• /
• pp.1697-1702
• /
• 2004

In this paper, we proposed the design and calibration method for the near infrared Acousto-Optic Tunable Filter (AOTF). The theory and design principles of AOTF for the visible light are well known since I.C.Chang has developed the parallel tangent condition for the non-collinear AOTF. Deflection angle, frequency-wavelength relation, spectral resolution, etc. were calculated based on the theory of AOTF. From this result, important parameters - incident and acoustic angle - to fabricate AOTF were decided. We measured the spectral resolution and the relation between electrical driving frequency and the Optical wavelength of diffracted light to calibrate the near infrared AOTF. About 40 ∼ 80 MHz electrical frequency was required to get 1200 ∼ 2200 nm near infrared light. Spectral resolution was less than 10 nm in the near infrared region.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.607-612
• /
• 2004

Spectral resolution enhancement method of Acousto-Optic Tunable Filter (AOTF) using incident light angle variation is described. AOTF is a small, mechanically rigid, high speed and spectral resolution light tunable filter. The basic theory of AOTF and its experimental verification is described. AOTF can generate two opposite polarized light simultaneously which wavelength can be changed by incident angle variation. We focused on the common region of two filtered light at the specific incident angle. This region can be used to enhance the spectral resolution of AOTF.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.105.4-105
• /
• 2001

This paper describes a newly designed multipoint process monitoring system based on a NIR acousto-optic tunable filter. The NIR multipoint process monitoring system consists of a NIR AOTF device for wavelength selection, an InGaAs array sensor, and a specially designed iin-line type of optical fiber probe. Unlike a FTS(Fourier Transform Spectrometry) or grating based monitoring system, an AOTF has no moving parts, and it can be rapidly tuned to any wavelength in its operating range within microseconds. Thus, the AOTF is advantageous in terms of faster spectral imaging capability and rigidity required for industrial monitoring environment. In the current feasibility evaluation, an enhanced optical fiber probe with 3 monitoring points was used. However, ...

• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.5
• /
• pp.89-95
• /
• 2008

The Acousto-Optic Tunable Filter (AOTF) is a high-speed full-field monochromator which generates two spectrally filtered light beams with ordinary and extraordinary polarization state. Thus, AOTF is widely used to build full-field spectral imaging system or spectral domain interferometer. However, AOTF has a big problem that the angle of diffracted light changes according to the scanning of wavelength, which makes image shift on CCD plane In this paper, we propose an analytic design of prism system to compensate the image shift. The detailed analysis of light paths in a prism and basic experimental results are presented to verify our proposed compensation method. The experimental results agree with simulation results based on suggested prism model and image shift is minimized at optimal condition. Also, it can be extended to compensate the image shift for ordinary and extraordinary polarized light simultaneously.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.10a
• /
• pp.59-60
• /
• 2009

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.8
• /
• pp.637-645
• /
• 1998

The characteristics of waveguide, electrode and packaging fabricated for acousto-optic tunable filters(AOTF) used for optical communications were analyzed. A $Ti:LiNbO_3$in-diffusing method was employed for the formation of the optical waveguide with a dimension of width $8{\mu}m$, length $30000-50000{\mu}m$ and varying the thickness. The diffusion was carried at $1050^{\circ}C$ for 8 hours to pattern the optical waveguide. The resulted waveguide exhibited a single mode at 1550nm optical wavelength. The width of IDT, with 10 SAM periods, was $5000{\mu}m$ . Impedances of the electrodes deposited with Au were analyzed using a network analyzer; $48.1\Omega$ at the center frequency of 193MHz for electrode thickness of $1500{\AA}$ and $50.7\Omega$ at the center frequency of 192MHz for $1600\AA$. And the characteristics of packaged AOTF was analyzed. When the electrical frequency 177.1MHz was applied to the device, the mode conversion efficiency was measured as 63% at the optical wavelength 1515nm.

• Proceedings of the Optical Society of Korea Conference
• /
• 2000.02a
• /
• pp.248-249
• /
• 2000

파장분할다중 광통신시스템은 파장통과 대역폭이 좁으면서, 파장통과 대역을 넓게 가변시킬 수 있는 집적광학형 광여파기를 필요로 하고 있다. 지금까지 전기광학효과$^{(1)}$ , 스트레인광학효과$^{(2)}$ , 음향광학효과$^{(3)}$ 들을 이용하여 다양한 형태의 광여파기들이 연구되어져왔다. 특히 음향광학효과를 이용한 편광모드변환형 가변파장 광필터 (AOTF: Acousto-Optic Tunable Filter)는 150nm 이상의 넓은 파장가변 범위, 1nm이하의 좁은 파장대역폭, 수 $\mu\textrm{s}$ 정도의 비교적 빠른 스위칭 속도, 그리고 여러 파장 채널을 동시에 선택할 수 있는 특성들 때문에 많은 연구가 진행되어져 왔다. 본 논문에서는 음향파 장벽(acoustic barrier)를 이용하여 표면 음향파(SAW: Surface Acoustic Wave)의 RF 구동파워를 감소시킬 수 있는 구조의 AOTF를 제작하고, 측정 결과를 음향파 장벽을 이용하지 않은 AOTF의 측정 결과와 비교, 검토하였다. (중략)

• Analytical Science and Technology
• /
• v.8 no.4
• /
• pp.1101-1108
• /
• 1995

Acousto-optic tunable filter is a compact, all solid state electronic dispersive device. It is based on the acousto-optic interaction in an anisotropic crystal. Compared to conventional grating monochromators. the AOTF has no moving parts, wider spectral tuning range (from UV through visible and near-IR to IR), higher throughput, higher resolution, faster scanning (${\mu}s$) and random wavelength access. These features make it possible to use the filter to develop novel instruments which are not possible otherwise. The instrument development and unique advantages of such AOTF based instruments including the multidimensional fluorimeter, the multiwavelength thermal lens spectrometer, and the detectors for HPLC and flow injection analysis are described.

• Korean Journal of Optics and Photonics
• /
• v.9 no.6
• /
• pp.413-416
• /
• 1998

We have flattened the gain of EDFA by using a long-period FBG filter and AOTF's. The gain and optical SNR characteristics of the gain-flattened EDFA in long-haul transmission been evaluated in a recirculating EDFA loop. The gain variation was less than 4.6 dB and the optical SNR was higher than 14 dB over 20-nm wavelength range when the optical signal went through the EDFA as many as 200 times. These results indicate that this gain-flattened EDFA is applicable for ultra long-haul WDM optical transmissions over 8000 km.

• Proceedings of the KIEE Conference
• /
• 2007.11a
• /
• pp.140-141
• /
• 2007

본 연구에서는 고분해능 및 고감도화된 시스템 개발을 위하여 AOTF를 이용하여 하이퍼스펙트럼 영상기법을 활용한 전임상 영상장비에 대한 연구를 수행하였다. 제작된 고감도 하이퍼스펙트럼 분자영상 시스템의 생물학적 적용을 위하여, AOTF의 파장 또는 진동수를 변화시키면서 GFP가 발현된 HEK 293 세포의 이미지를 촬영하였다. 또한, 제작된 실험 대상물 이미지화 시스템을 이용해서 실험용 쥐의 이미지를 촬영하였다. 실험용 쥐를 크세논 아크램프 사용 전 후 이미지를 촬영한 결과 크세논 아크 램프 사용 후에는 청색의 선명한 영상을 얻을 수 있었다.