Browsing by Author "Yeh, C. -H."

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Employing dual-saturable-absorber-based filter for stable and tunable erbium-doped fiber ring laser in single-frequency
(2011-05-01)
Yeh, C. -H.
;
Chow, C. -W.
;
Chen, K. -H.
;
Chen, J. -H.
;
光電工程學系
In this demonstration, a stable and wavelength-tunable erbium-doped fiber (EDF) ring laser using dual-saturable-absorber-based (DSAB) filter inside loop cavity is proposed and experimentally investigated. The proposed DSAB filter not only can filter the side-mode in single-frequency output, but also can obtain the flattened output power spectrum within 1 dB variation in the effectively range of 1529 to 1563 nm. In addition, the output stabilities of wavelength and power are also measured experimentally and discussed.
Gain flattened erbium-doped amplifier with 34 nm flat bandwidth
(2006-09-14)
Yeh, C. -H.
;
Lin, M. -C.
;
Chi, S.
;
光電工程學系
;
Department of Photonics
A gain-flattened two-stage erbium-based fibre amplifier module, structured by an erbium-doped waveguide amplifier and an erbium-doped fibre amplifier in serial, is proposed and demonstrated experimentally. In an operating range of 1528 to 1562 nm, all the gain is above 35 d13 and the noise figure is distributed from 5.5 to 6.7 dB, and +/- 1.1 dB maximum gain variation is retrieved at an input saturation power of -25 dBm. As a result, the proposed amplifier not only enhances gain value but possesses flatness in the operating region.
Multiwavelength erbium fiber ring laser using Sagnac loop and Fabry-Perot laser diode
(2008)
Yeh, C. -H.
;
Shih, F-Y
;
Chen, C. -T
;
Lee, C. -N.
;
Chi, S.
We propose and demonstrate experimentally a simply multiple-wavelength erbium compound ring fiber laser employing a Sagnac interferometer with erbium-doped fiber amplifier (EDFA) and Fabry-Perot laser diode (FP-LD). The proposed laser has the advantage of simply structure and easy fabrication, lower insertion loss and cost-effective. Based on the Sagnac fiber laser scheme, the proposed laser can lase eight wavelengths simultaneously. Moreover, the optical output stability of the ring laser has been also discussed.
Simply self-restored ring-based time-division-multiplexed passive optical network
(2008-04-01)
Yeh, C. -H.
;
Lee, C. -S.
;
Chi, S.
;
光電工程學系
;
Department of Photonics
A simply self-restored ring-based time-division-multiplexed passive optical network by a clockwise and counterclockwise circulating fiber against the fiber fault in an access system is proposed and experimentally investigated. The proposed optical line terminal and optical network unit modules can be used to prevent and protect the occurrence of fiber failure in the ring-based passive optical networks (PONs). Using the proposed self-healing access network, the ring-based PON can be revived promptly under fiber failure. The protection and restoration time of the access network is measured within 7 ms. In addition, the performance of data traffic in the access network is also discussed. (C) 2008 Optical Society of America.
Tunable S-band erbium-doped triple-ring laser with single-longitudinal-mode operation
(2007-01-22)
Yeh, C. -H.
;
Huang, T. -T.
;
Chien, H. -C.
;
Ko, C. -H.
;
Chi, S.
We propose and demonstrate a tunable and stable single-longitudinal-mode (SLM) erbium fiber laser with a passive triple-ring cavity structure in S-band operation. The proposed laser is fundamentally structured by using three different lengths of ring cavities, which serve as the mode filters. When a mode-restricting intracavity fiber Fabry-Perot tunable filter (FFP-TF) is combined, the proposed resonator can guarantee a tunable and stable SLM laser oscillation. Moreover, the performances of the output power, wavelength stability, tuning range, and side-mode suppression ratio (SMSR) are studied. (c) 2007 Optical Society of America.
Using dual ring structure with different coupling ratio for S-band erbium-based fiber laser
(2008-01-01)
Yeh, C. -H.
;
Lee, C. -N.
;
Shih, F. -Y.
;
Chi, S.
;
光電工程學系
An S-band erbium-doped fiber (EDF) ring laser, using a dual coupler ring structure (DCRS) with different coupling ratio injection, is proposed and demonstrated experimentally. The proposed fiber ring laser does not use any fiber Bragg gratings or etalon filters (passive or active filter) into the loop cavity to lase a single wavelength. This proposed fiber laser has an optical signal to noise ratio (OSNR) of > 38.2 dB and output power of - 3.8 dBm at 1506.28 nm, while the coupling ratio in a ring cavity is 10%. Moreover, the performances of output power and wavelength stabilities have also been studied and discussed. [GRAPHICS] Output ASE spectrum of the S-band EDFA while the pumping power operates at 280 mW (C) 2008 by Astro Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA.
Using dual-mode self-locked semiconductor laser for optical millimeter-wave application
(2011-03-01)
Yeh, C. -H.
;
Chow, C. -W.
;
Liu, Y. -F.
;
Pan, C. -L.
;
光電工程學系
In this study, an optical millimeter-wave (mm-wave) generator is proposed and experimentally demonstrated by using a self-injected Fabry-Perot laser diode (FP-LD), having mode spacing of 1.11 nm, for dual-mode beating in 140 GHz band (terahertz band). The created dual-wavelength also can be also modulated at 1.25, 2.5, and 10 Gb/s with on-off keying (OOK) modulation format by external optical modulator, respectively, in 20 km fiber transmission. Moreover, the dual-mode laser can be selected in difference wave-lengths by tuning the optical filter inside cavity for the future WDM applications.
Utilizing erbium fiber ring scheme and Fabry-Perot laser diode for stable and wavelength-tunable laser in single-longitudinal-mode output
(2011-02-01)
Yeh, C. -H.
;
Chow, C. -W.
;
Pan, C. -L.
;
光電工程學系
;
Department of Photonics
In this investigation, we propose and demonstrate a stable and wavelength-tunable erbium-doped fiber (EDF) ring laser scheme with external-injected Fabry-Perot laser diode (FP-LD) technology, in single-longitudinal-mode (SLM) output behavior. Here, the output power and side-mode suppression ratio (SMSR) of the proposed laser scheme can be obtained between -3.9 and 1.3 dBm and 30.1 and 50.5 dB in the operating wavelengths of 1523.65 and 1561.50 nm with 1.12 nm tuning step, respectively, according to the output mode-spacing of FP-LD used. Besides, the lasing stabilities of output power and wavelength are also investigated and discussed.
Wavelength-selection erbium fiber laser with single-mode operation using simple ring design
(2010-04-01)
Yeh, C. -H.
;
Chow, C. -W.
;
Chang, Y. -C.
;
光電工程學系
;
光電工程研究所
In this demonstration, we propose and experimentally investigate a wavelength-selection erbium-doped fiber (EDF) laser in single-longitudinal-mode (SLM) by using simple fiber ring scheme design. We use a tunable bandpass filter (TBF) inside the gain cavity to restrict the lasing frequency. The proposed ring cavities can also serve as the mode filters for side mode suppression. Based on the simple ring cavity design, the mode hopping can be avoided to achieve SLM output. The TBF inside the laser scheme also obtains the wavelength tuning in the range of 1520.02 to 1562.02 nm. In addition, the output performance of the proposed fiber laser has also been discussed.
Wavelength-selection erbium fiber laser with single-mode operation using simple ring design
(2010-04-01)
Yeh, C. -H.
;
Chow, C. -W.
;
Chang, Y. -C.
;
光電工程學系
;
Department of Photonics
In this demonstration, we propose and experimentally investigate a wavelength-selection erbium-doped fiber (EDF) laser in single-longitudinal-mode (SLM) by using simple fiber ring scheme design. We use a tunable bandpass filter (TBF) inside the gain cavity to restrict the lasing frequency. The proposed ring cavities can also serve as the mode filters for side mode suppression. Based on the simple ring cavity design, the mode hopping can be avoided to achieve SLM output. The TBF inside the laser scheme also obtains the wavelength tuning in the range of 1520.02 to 1562.02 nm. In addition, the output performance of the proposed fiber laser has also been discussed.