Browsing by Author "Li, Yi-Cheng"

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20-Gbps WDM-PON transmissions employing weak-resonant-cavity FPLD with OFDM and SC-FDE modulation formats
(2013-04-08)
Lu, I-Cheng
;
Wei, Chia-Chien
;
Jiang, Wen-Jr
;
Chen, Hsing-Yu
;
Chi, Yu-Chieh
Using a colorless weak-resonant-cavity (WRC) FPLD injected by a centralized light source, we have experimentally demonstrated a superior performance of 20-Gbps uplink transmission in a WDM-PON. Even though the typical modulation bandwidth of a WRC-FPLD is only similar to 1.25 GHz, using spectrally-efficient 32-QAM OFDM or SC-FDE modulation, 20-Gbps uplink signals can achieve the FEC limit after 25-km dispersion-uncompensated single-mode fiber transmission. Because of the advantage of lower PAPR, the SC-FDE signals outperform the OFDM signals with the fixed 32-QAM format in the proposed system; moreover, SC-FDE scheme can be another promising candidate for uplinks in WDM-PONs, for its simplification to ONUs. The signal at the mode of 1560.7 nm shows similar quality with the signal at the modes of 1545.3 nm and 1574.7 nm, the WRC-FPLD, accordingly, has wide injection wavelength range from at least 1545.3 nm to 1574.7 nm. With the mode spacing of 0.55 nm, consequently, we have demonstrated the applicability of the colorless WRC-FPLD on supporting up to 36 channels in the WDM-PON. (C) 2013 Optical Society of America
Coherently wavelength injection-locking a 600-mu m long cavity colorless laser diode for 16-QAM OFDM at 12 Gbit/s over 25-km SMF
(2013-07-15)
Li, Yi-Cheng
;
Chi, Yu-Chieh
;
Cheng, Min-Chi
;
Lu, I-Cheng
;
Chen, Jason
The coherent injection-locking and directly modulation of a long-cavity colorless laser diode with 1% end-facet reflectance and weak-resonant longitudinal modes is employed as an universal optical transmitter to demonstrated for optical 16-QAM OFDM transmission at 12 Gbit/s over 25 km in a DWDM-PON system. The optimized bias current of 30 mA (similar to 1.5Ith) with corresponding extinction ratio (ER) of 6 dB and the external injection power of -9 dBm is (are) required for such a wavelength-locked universal transmitter to carry the 16-QAM and 122-subcarrier formatted OFDM and data-stream. By increasing external injection-locking from. 9 dBm to 0 dBm, the peak-to-peak chirp of the OFDM data stream reduces from 7.7 to 5.4 GHz. The side mode suppression ratio (SMSR) of up to 50 dB is achieved with wider detuning range between -0.5 nm to 2.0 nm under an injection power of 0 dBm. By modulating such a colorless laser diode with an OFDM data stream of 122 subcarriers at a central carrier frequency of 1.5625 GHz and a total bandwidth of 3 GHz, the transmission data rate of up to 12 Gbit/s in standard single-mode fiber over 25 km is demonstrated to achieve an error vector magnitude (EVM) of 5.435%. Such a universal colorless DWDM-PON transmitter can deliver the optical OFDM data-stream at 12 Gbit/s QAM-OFDM data after 25-km transmission with a receiving power sensitivity of -7 dBm at BER of 3.6x10(-7) when pre-amplifying the OFDM data by 5 dB. (C) 2013 Optical Society of America
Nitrilotriacetic acid-coated magnetic nanoparticles as affinity probes for enrichment of histidine-tagged proteins and phosphorylated peptides
(2007-10-01)
Li, Yi-Cheng
;
Lin, Ya-Shiuan
;
Tsai, Pei-Jane
;
Chen, Cheng-Tai
;
Chen, Wei-Yu
We herein demonstrate superparamagnetic Fe3O4 nanoparticles coated with nitrilotriacetic acid derivative (NTA) that can bind with different immobilized metal ions are capable of probing diverse target species. Immobilized Ni(II) on the surfaces of the NTA-magnetic nanoparticles have the capability of selectively trapping histidine (His)tagged proteins such as a mutated streptopain tagged with 6x His, i.e., C192S (MW similar to 42 kDa), from cell lysates. Enrichment was achieved by vigorously mixing the sample solution and the nanoparticles by pipetting in and out of a sample vial for only 30 s. After enrichment, the probe-target species could be readily isolated by magnetic separation. We also characterized the proteins enriched on the affinity probes using on-probe tryptic digestion under microwave irradiation for only 2 min, followed by matrix-assisted laser desorption/ionization mass spectrometry analysis. Using this enrichment and tryptic digestion, the target species can be rapidly enriched and characterized, reducing the time required for carrying out the complete analysis to less than 10 min. Furthermore, when either Zr(IV) or Ga (III) ions are immobilized on the surfaces of the NTA-magnetic nanoparticles, the nanoparticles have the capability of selectively enriching phosphorylated peptides from tryptic digests of alpha-, beta-caseins, and diluted milk. The detection limit for the tryptic digests of alpha- and,beta-caseins is similar to 50 finol.
Using a L-Band Weak-Resonant-Cavity FPLD for Subcarrier Amplitude Pre-Leveled 16-QAM-OFDM Transmission at 20 Gbit/s
(2013-04-01)
Lin, Gong-Ru
;
Chi, Yu-Chieh
;
Li, Yi-Cheng
;
Chen, Jyehong
;
光電工程學系
A directly modulated and coherently injection-locked WRC-FPLD transmitter is preliminarily employed to perform the 16-QAM-OFDM data transmission by using an OFDM subcarrier amplitude pre-leveling technique. The maximum transmission bit-rate of 20-Gbit/s is reported by fusing the OFDM subcarrier pre-leveling with the coherent injection-locking techniques in such a directly modulated WRC-FPLD. Without pre-leveling the OFDM subcarrier, the coherently injection-locked L-band WRC-FPLD suppresses its mode-partition noise to improve the EVM of the 16-QAM-OFDM data only from 13.52% to 10.2%. The OFDM subcarrier pre-leveling effectively compensate the finite bandwidth and unflattened modulating response of the injection-locked WRC-FPLD to improve the transmission EVM and SNR performances. The received constellation plot reveals that the EVM and SNR of the back-to-back transmitted 16-QAM-OFDM data are significantly improved to 5.58% and 17 dB, respectively. With the use of both injection-locking and pre-leveling techniques, the directly 16-QAM-OFDM modulated WRC-FPLD transmitter can reach the FEC limited BER of 3.8 x 10(-3) at a receiving power sensitivity of -10 dBm. The OFDM subcarrier pre-leveling technique helps the WRC-FPLD to reduce the overall BER of 16-QAM-OFDM data by one order of magnitude, providing a minimum BER of 4.5 x 10(-5) at a receiving power of -2 dBm.