SS-OCT용 파장 스위핑 레이저를 위한 스위핑 중심 세팅 자동화

엄진섭,Eom, Jinseob 한국센서학회 2017 센서학회지 Vol.26 No.5

In this paper, the automation of sweeping center setting for wavelength swept laser used in SS-OCT has implemented. For 3 regions where the initial FFP-TF pass wavelength can be located, each different DC voltage pattern is applied to FFP-TF. Through its performance test to the laser, fast and exact setting to sweeping central wavelength, flat sweeping with ${\pm}0.5dB$ fluctuation range, and 10 mW average optical power were obtained. This shows that the realized automatic setting process can replace an inconvenient manual setting operation used for current wavelength swept laser. Additionally it cuts costs for optical spectrum analyzer necessary to laser spectrum monitoring.

파장 스위핑 레이저의 스위핑 선형화

엄진섭,Eom, Jinseob 한국전기전자학회 2018 전기전자학회논문지 Vol.22 No.3

본 논문에서는 선형으로 스위핑하는 파장 스위핑 레이저를 구현하기 위한 새로운 방식을 제안하였으며, 레이저 제작 및 실험을 통하여 1kHz 속도, 80nm 구간의 선형 스위핑 특성을 확인하였다. 제안된 방식은 FFP-TF 인가 파형에 대한 초기 한번의 선 보정만을 필요로 한다. 따라서 기존의 비선형 스위핑 레이저에서 불가피한 후 보정 과정의 번거로움 및 시간 소모문제를 해결해 준다. In this paper, a new method for linear sweeping of wavelength swept laser has proposed, and the linear sweeping of 1kHz speed and 80nm range has realized by using this method. The proposed requires only one-shot calibration in the early stage on a wave pattern applied to FFP-TF. This makes the problem with nonlinear swept lasers like a cumbersome and time-consuming signal processing brought on by every recalibration to be resolved.

SS-OCT용 파장 스위핑 레이저를 위한 자동 스위프 평탄화

엄진섭 ( Jinseob Eom ) 한국센서학회 2017 센서학회지 Vol.26 No.1

In this paper, the automatic sweep flattening for wavelength swept laser of SS-OCT has implemented. Through its performance test applied to the laser, 50 nm flat sweeping range, ±0.5 dB fluctuation range, 22 sec the time required, and 10 mW average optical power were obtained. This shows that the realized automatic process can replace the inconvenient manual operation used for polarization con-trol of current sweeping laser. Additionally it cuts costs for optical spectrum analyzer necessary to sweep monitoring.

파장 선형 스위핑 레이저를 이용한 광섬유 격자 센서의 스트레인 측정

엄진섭 ( Jinseob Eom ) 한국센서학회 2021 센서학회지 Vol.30 No.6

In this study, linearized sweeping of a wavelength sweeping laser was realized. This technique was used to measure the strain on a fiber Bragg grating(FBG) sensor. For linear sweeping, PID control over the wavelength difference between linear and nonlinear sweeping was employed. The performance test showed that linear sweeping with a 46 nm range and a 1 kHz frequency held up well with a 99.5% decrement in nonlinearity after the 120th feedback. When attached to a strain gage, the FBG sensor registered strain that matched the data sheet within a difference of 4.5[με]. Altogether, linear sweeping can play a leading role in monitoring a safety of large SOC structures as well as in other wavelength sweeping laser related fields.

온도 및 전류의 과도응답 제어가 가능한 SOA Driver에 관한 연구

엄진섭(Jinseob Eom) 한국조명·전기설비학회 2014 조명·전기설비학회논문지 Vol.28 No.2

In this paper, SOA Current and Temperature Driver which consisted of LabVIEW programming part capable of current and temperature transient response pattern design, DAQ module for analog voltage in&out, and voltage to current converting chips has realized. The output current(possible to 3A) from the Driver to SOA was clearly constant without ripple and also showed no variance until 1mA unit for a long time operation. The temperature of TEC took several seconds to reach a set temperature, and were maintained stably within ± 0.1℃ for several hours. The proposed Driver can replace the previous high cost SOA Drivers for wavelength swept lasers fully and provides the convenience of transient response design capability for current and temperature.

SS-OCT용 정현파 및 트리거 펄스 발생기

엄진섭 ( Jinseob Eom ) 한국센서학회 2015 센서학회지 Vol.24 No.6

In this paper, the sine-wave and trigger pulse generator with capability of frequency high-resolution and time-variable trigger edge has implemented. It fulfills well the requirements for SS-OCT with frequency resolution of 1 Hz, frequency stability of ≤ ±0.03 Hz and time-variable trigger edge. Through its performance test applied to the wavelength swept laser, 90 nm, sweeping range and 10mW average optical power were obtained. This showes that the realized generator can replace the commercial high cost and high performance signal generators employed by current SS-OCT systems.

온도 안정화 전달함수 도출 및 이의 시뮬레이션에 의한 PID 계수 결정에 관한 연구

엄진섭 ( Jinseob Eom ) 한국센서학회 2015 센서학회지 Vol.24 No.6

In this paper, a new method for obtaining PID coefficients which are essential to a temperature stabilization process has been proposed. This method starts from measuring the open loop transfer function of the module, then the closed loop transfer function embodying PID control can be produced based on this. Finally, the simulations using a few PID coefficients and the performance analysis for those results provide the best PID coefficients which are effective in a fast setting to a target temperature, a less current needed, and less deviation from steady state. The measurement using the derived PID coefficients,K _{p} =1.6,K _{i} =0.8,K _{d} =0.3 showed T _{s} =7.4[sec],%OS=16, and stabilization within ±0.02[oC] for several hours. In addition to light sources like SOA, the proposed method can be utilized for any device needs temperature stabilization.

마이켈슨 간섭계를 이용한 새로운 파장 잠금 방법

박경수,엄진섭,Park Kyoungsu,Eom Jinseob 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.5a

본 논문에서는 팔 길이 가변 마이켈슨 간섭계를 이용한 파장 잠금 구조를 새로이 제안하였다. 제안된 구조는 LD 드라이버, 마이켈슨 간섭계, ATC, APC, 신호처리부로 구성된다. 이 구조에서는 0.0005nm(=62.4MHz)이하의 정밀도로 파장 잠금이 가능하며, 마이켈슨 간섭계의 팔 길이가변성을 이용하여 주위 환경변화에 따른 문제점들에 쉽게 대처할 수 있다. In this paper, we propose a new wavelength locking structure which uses the Michelson interferometer equipped with a movable arm. The proposed one consists of LD driver, Michelson interferometer, automatic temperature controller, automatic power controller, and signal processor. This structure can provide the wavelength locking capability of a resolution below 0.0005nm(=62.4MHz) and cope easily with an external environment variation using movable arm of Michelson interferometer to give a good stability.

구조물 안전 모니터링용 파장 스위핑 레이저를 위한 스위핑 자동 선형화

이덕규 ( Duk-kyu Lee ),엄진섭 ( Jinseob Eom ) 한국센서학회 2020 센서학회지 Vol.29 No.1

In this study, a novel method for sweeping automatic linearization of wavelength swept laser is proposed. Through the test performed on the implemented laser, the linear sweeping is held up well with a 97% decrease in nonlinearity, and 60 nm sweeping range, 1 kHz sweeping frequency, and 8.8 mW average optical power were obtained. The proposed method uses fiber Bragg grating array, optical-electronic conversion circuit, FPGA embedded module, and a LabVIEW program to generate new compensated wave patterns which were applied to the fiber Fabry-Perot tunable filter. Linear sweeping can reduce the cumbersome and time-consuming recalibration process required for nonlinear sweeping. Additionally, the proposed method provides more accurate measurement results for the structure safety monitoring system.

전류 패턴의 설계가 가능한 SOA Dimming Driver에 관한 연구

이주찬(Juchan Lee),엄진섭(Jinseob Eom) 한국조명·전기설비학회 2013 조명·전기설비학회논문지 Vol.27 No.2

In this paper, the low cost SOA Dimming Driver which consisted of LabVIEW programming part capable of current pattern design, DAQ module for analog voltage output, and voltage to current converter has realized. The output current(possible to 3A) from the Driver was clearly constant without ripple and also showed no variance until 1mA unit for a long time operation. The proposed low cost Driver can replace the previous high cost SOA Drivers for wavelength swept lasers fully and provide the convenience and safety of auto-supplying a designed current pattern.