FBG sensor system based on wavelength-swept active mode-locking laser with RSOA gain medium

2011 ◽  
Author(s):  
Hyo-jin Kim ◽  
Hwi Don Lee ◽  
Myong Yung Jeong ◽  
Chang-Seok Kim ◽  
Ju Han Lee
Keyword(s):  
Mode Locking ◽  
Gain Medium ◽  
Sensor System ◽  
Active Mode ◽  
Fbg Sensor

Active mode-locking of an external cavity GaInAsP laser incorporating a fibre-grating reflector

1988 ◽  
Vol 24 (23) ◽  
pp. 1439 ◽  
Author(s):  
D. Burns ◽  
D.W. Crust ◽  
J.T.K. Chang ◽  
W. Sibbett
Keyword(s):  
External Cavity ◽  
Mode Locking ◽  
Active Mode

scholarly journals Dual-band wavelength-swept active mode locking laser for multi-band fiber-optic sensors

2012 ◽  
Author(s):  
Hwi Don Lee ◽  
Chang Seok Kim ◽  
Myung Young Jeong ◽  
Zhongping Chen
Keyword(s):  
Fiber Optic ◽  
Mode Locking ◽  
Fiber Optic Sensors ◽  
Dual Band ◽  
Active Mode ◽  
Multi Band

Phase characteristics of pulses from an Nd : YAG laser with active mode locking

1997 ◽  
Vol 27 (11) ◽  
pp. 968-971
Author(s):  
A A Apolonskii ◽  
V P Drachev ◽  
Yu I Krasnikov ◽  
S V Perminov
Keyword(s):  
Mode Locking ◽  
Yag Laser ◽  
Active Mode

Active mode-locking of conventional diode laser by using external cavity

1990 ◽  
Vol 78 (5-6) ◽  
pp. 369-372 ◽  
Author(s):  
Hiroki Nakatsuka ◽  
Kazi Monowar Abedin ◽  
Sadao Uemura
Keyword(s):  
Diode Laser ◽  
External Cavity ◽  
Mode Locking ◽  
Active Mode

scholarly journals Phase stable swept-source optical coherence tomography with active mode-locking laser for contrast enhancements of retinal angiography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kwan Seob Park ◽  
Eunwoo Park ◽  
Hwidon Lee ◽  
Hyun-Ji Lee ◽  
Sang-Won Lee ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Phase Stability ◽  
Averaging Method ◽  
Mode Locking ◽  
Optical Coherence ◽  
Swept Source ◽  
Active Mode ◽  
Coherent Averaging ◽  
Noise Ratio ◽  
High Phase

AbstractSwept-source optical coherence tomography (SS-OCT) is an attractive high-speed imaging technique for retinal angiography. However, conventional swept lasers vary the cavity length of the laser mechanically to tune the output wavelength. This causes sweep-timing jitter and hence low phase stability in OCT angiography. Here, we improve an earlier phase-stabilized, akinetic, SS-OCT angiography (OCTA) method by introducing coherent averaging. We develop an active mode-locking (AML) laser as a high phase-stable akinetic swept source for the OCTA system. The phase stability of the improved system was analyzed, and the effects of coherent averaging were validated using a retina phantom. The effectiveness of the coherent averaging method was further confirmed by comparing coherently and conventionally averaged en face images of human retinal vasculature for their contrast-to-noise ratio, signal-to-noise ratio, and vasculature connectivity. The contrast-to-noise ratio was approximately 1.3 times larger when applying the coherent averaging method in the human retinal experiment. Our coherent averaging method with the high phase-stability AML laser source for OCTA provides a valuable tool for studying healthy and diseased retinas.

scholarly journals Intensity and Wavelength Division Multiplexing FBG Sensor System Using a Raman Amplifier and Extreme Learning Machine

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yibeltal Chanie Manie ◽  
Run-Kai Shiu ◽  
Peng-Chun Peng ◽  
Bao-Yi Guo ◽  
Mekuanint Agegnehu Bitew ◽  
...  
Keyword(s):  
Extreme Learning Machine ◽  
Wavelength Division Multiplexing ◽  
Sensor System ◽  
Bragg Wavelength ◽  
Wavelength Division ◽  
Raman Amplifier ◽  
Fbg Sensor ◽  
Transmission Distance ◽  
Fbg Sensors ◽  
Learning Machine

A fiber Bragg grating (FBG) sensor is a favorable sensor in measuring strain, pressure, vibration, and temperature in different applications, such as in smart structures, wind turbines, aerospace, industry, military, medical centers, and civil engineering. FBG sensors have the following advantages: immune to electromagnetic interference, light weight, small size, flexible, stretchable, highly accurate, longer stability, and capable in measuring ultra-high-speed events. In this paper, we propose and demonstrate an intensity and wavelength division multiplexing (IWDM) FBG sensor system using a Raman amplifier and extreme learning machine (ELM). We use an IWDM technique to increase the number of FBG sensors. As the number of FBG sensors increases and the spectra of two or more FBGs are overlapped, a conventional peak detection (CPD) method is unappropriate to detect the central Bragg wavelength of each FBG sensor. To solve this problem, we use ELM techniques. An ELM is used to accurately detect the central Bragg wavelength of each FBG sensor even when the spectra of FBGs are partially or fully overlapped. Moreover, a Raman amplifier is added to a fiber span to generate a gain medium within the transmission fiber, which amplifies the signal and compensates for the signal losses. The transmission distance and the sensing signal quality increase when the Raman pump power increases. The experimental results revealed that a Raman amplifier compensates for the signal losses and provides a stable sensing output even beyond a 45 km transmission distance. We achieve a remote sensing of strain measurement using a 45 km single-mode fiber (SMF). Furthermore, the well-trained ELM wavelength detection methods accurately detect the central Bragg wavelengths of FBG sensors when the two FBG spectra are fully overlapped.

Active mode-locking through loss modulation: Chirped pulse solutions

1988 ◽  
Vol 68 (3) ◽  
pp. 213-219 ◽  
Author(s):  
M. Morin ◽  
M. Piche ◽  
R. Tremblay
Keyword(s):  
Mode Locking ◽  
Active Mode ◽  
Chirped Pulse ◽  
Loss Modulation

scholarly journals ACTIVE MODE-LOCKING OF A DIODE-PUMPED Ce, Nd: YAG

1991 ◽  
Vol 01 (C7) ◽  
pp. C7-303-C7-306
Author(s):  
C. ECKERT ◽  
B. CUNIN ◽  
J. A. MIEHE
Keyword(s):  
Mode Locking ◽  
Active Mode ◽  
Diode Pumped
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