Quasi-distributed fiber sensor using active mode locking laser cavity with multiple FBG reflections

2017 ◽  
Author(s):  
Chang Hyun Park ◽  
Gyeong Hun Kim ◽  
Chang-Seok Kim ◽  
Hwi Don Lee ◽  
Youngjoo Chung
Keyword(s):  
Laser Cavity ◽  
Mode Locking ◽  
Fiber Sensor ◽  
Active Mode

scholarly journals Quasi-Distributed Active-Mode-Locking Laser Interrogation with Multiple Partially Reflecting Segment Sensors

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4128
Author(s):  
Chang Park ◽  
Gyeong Kim ◽  
Suck Hong ◽  
Hwi Lee ◽  
Chang-Seok Kim
Keyword(s):  
Laser Cavity ◽  
Length Change ◽  
Mode Locking ◽  
Segment Length ◽  
Length Variation ◽  
Active Mode ◽  
Distributed Sensor ◽  
Fabry Perot ◽  
New Type ◽  
The Difference

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.

Characterization and experimental verification of actively mode-locked erbium doped fiber laser utilizing ring cavity

2020 ◽  
Vol 87 (9) ◽  
pp. 535-541
Author(s):  
Shaymaa Riyadh Tahhan ◽  
Ahmad Atieh ◽  
Mehedi Hasan ◽  
Trevor Hall
Keyword(s):  
Bandpass Filter ◽  
Ring Cavity ◽  
Laser Cavity ◽  
Mode Locking ◽  
Tunable Filter ◽  
Filter Bandwidth ◽  
Active Mode ◽  
Pulse Trains ◽  
Erbium Doped ◽  
Mode Locked Laser

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.

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.

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
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