Dynamic strain measurement of identical weak FBG array based on active mode locking laser cavity

Author(s):  
Gyeong Hun Kim ◽  
Hwi Don Lee ◽  
Youngjoo Chung ◽  
Chang-Seok Kim

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4128
Author(s):  
Chang Park ◽  
Gyeong Kim ◽  
Suck Hong ◽  
Hwi Lee ◽  
Chang-Seok Kim

A new type of quasi-distributed sensor system is implemented using an active mode locking (AML) laser cavity with multiple partially reflecting segments. The mode locking frequency of the AML laser is linearly proportional to the overall lasing cavity length. To implement multiple resonators having multiple reflection points installed in a sensing fiber, two types of partial reflectors (PRs) are implemented for an in-line configuration, one with fiber Bragg grating and the other with a fiber Fabry–Perot interferometer. Since the laser has oscillated only when the modulation frequencies for the mode locking frequency match with the corresponding resonator lengths, it is possible to read the multiple partially reflecting segments along the sensing fiber. The difference between two corresponding mode locking frequencies is changing proportionally with the segment length variation between two PRs upon strain application. The segment length change caused by the applied strain can be successfully measured with a linear sensitivity between mode locking frequency and displacement, linearity over 0.99, and spatial position resolution below meter order.



2017 ◽  
Author(s):  
Chang Hyun Park ◽  
Gyeong Hun Kim ◽  
Chang-Seok Kim ◽  
Hwi Don Lee ◽  
Youngjoo Chung


2017 ◽  
Author(s):  
Gyeong Hun Kim ◽  
Joon Young Kim ◽  
Chang Hyun Park ◽  
Chang-Seok Kim ◽  
Hwi Don Lee ◽  
...  


2020 ◽  
Vol 87 (9) ◽  
pp. 535-541
Author(s):  
Shaymaa Riyadh Tahhan ◽  
Ahmad Atieh ◽  
Mehedi Hasan ◽  
Trevor Hall

AbstractA simple active mode-locked erbium-doped fiber (EDF) ring laser is characterized and experimentally demonstrated. The active mode-locked laser can be tuned in the C-band wavelength range 1525 nm to 1565 nm using a tunable bandpass filter placed in the cavity. An intensity modulator placed inside the laser cavity is driven using a sinusoidal signal at different repetition rates. The laser can produce trains of pulses with a width that is controlled using the mode-locking order. The experiments demonstrated an active mode-locked laser that can generate pulse trains with 39 ns width at multiple cavity fundamental frequency of 0.67 MHz repetition rate. Numerical simulations are conducted to investigate the effect of the tunable filter bandwidth and the power of the EDF 980 nm pump on the mode-locking process and produced pulses width.



1988 ◽  
Vol 24 (23) ◽  
pp. 1439 ◽  
Author(s):  
D. Burns ◽  
D.W. Crust ◽  
J.T.K. Chang ◽  
W. Sibbett


2012 ◽  
Author(s):  
Hwi Don Lee ◽  
Chang Seok Kim ◽  
Myung Young Jeong ◽  
Zhongping Chen


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


1990 ◽  
Vol 78 (5-6) ◽  
pp. 369-372 ◽  
Author(s):  
Hiroki Nakatsuka ◽  
Kazi Monowar Abedin ◽  
Sadao Uemura


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