Browsing by Author "Tsao, Cheng"

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2.5 dB sensitivity improvement by optimizing the driving voltage of an MZM and electrical filter bandwidth of optical duobinary transmission systems
(2006)
Lu, Yu-Chang
;
Wei, Chia-Chien
;
Chen, Jason (Jyehong)
;
Tsao, Cheng
;
Chi, Sien
We numerically and experimentally demonstrated that 100% driving voltage doesn't necessarily yield optimal results in duobinary systems. Compared with conventional condition, a 2.5 dB sensitivity improvement is obtained using 3 GHz LPFs with optimum voltage. (C) 2006 Optical Society of America.
Effects of filter bandwidth and driving voltage on optical duobinary transmission systems
(2007-07-01)
Lu, Yu Chang
;
Wei, Chia Chien
;
Chen, Jason (Jyehong)
;
Feng, Kai Ming
;
Yeh, Pao Chi
This work demonstrates how electrical driving voltage of a Mach-Zehnder modulator and the bandwidth of electrical low-pass filters (LPFs) affect optical duobinary signals. The fact that a 100% driving voltage does not necessarily yield optimal results in duobinary systems is established both numerically and experimentally. Various filter bandwidths correspond to respective optimum driving voltages. In a 10 Gbps duobinary system, compared with the conventional condition of using a 2.5 GHz electrical LPF, a 2.5 dB sensitivity improvement is obtained by employing a 3 GHz LPF with an 88% driving voltage of fully driving. (c) 2007 Published by Elsevier Inc.
Evaluation of the inherent ripple effects on the performance of an optical DQPSK signal generated by using only one MZM
(2006)
Peng, Wei-Ren
;
Chen, Jason (Jyehong)
;
Tsai, Shen-You
;
Tsao, Cheng
;
Chi, Sien
We analytically computed the optical spectra and numerically evaluated the ripple impacts on the performance of an optical DQPSK signal generated by only one MZM. We confirmed the necessity of a pulse carver to this kind of signal. The tolerances to the timing mismatch between the data and the pulse carver were analyzed among different duty-cycles. The conventional DQPSK signal generated by two parallel DPSK modulators were also analyzed for comparisons. We also provided some experimental results to demonstrate the possibility of the one-MZM scheme and the necessity of a pulse carver in terms of the clearly opened demodulated eyes.