A derivative and subtractive equalization (DSE), which simultaneously transmits both four-level pulse amplitude modulation (PAM-4) and discrete multitone (DMT) signals encoded by quadrature amplitude phase shift keying (QPSK) with the same bandwidth, is proposed. The proposed DSE recovers the DMT signal by tracking the change of derivative value between adjacent sampling points and then subtracting the recovered PAM-4 signal after derivative value tracking from the received signals. A 20-km optical link is implemented to experimentally verify the proposed DSE technique. The bit error rate (BER) of the PAM-4 signal (1 Gbaud) and the error vector magnitude (EVM) of QPSK signal (1 Gbaud) are measured in order to examine the difference in transmission performance before and after using the proposed DSE technique. The 20% EVM of QPSK signal and the 5.4 × 10 − 5 BER of PAM-4 signal is observed at the 25% power ratio of DMT signal to PAM-4 signal. It is found that the signal-to-noise ratio of input PAM-4 and DMT signal should be 25 and 40 dB, respectively, with the 7% forward error correction to successfully transmit them at the same time. The 4-dB power penalty is observed before and after using DSE technique. These experimental results tell us that the transmission capacity of 4 times the bandwidth can be achieved using the proposed DSE technique.
KEYWORDS: Light emitting diodes, Resistance, Thermal analysis, Temperature metrology, Time metrology, LED lighting, Packaging, Thermal modeling, Solid state lighting, LED displays
Thermal analysis of wafer-level packaged LEDs with red, green and blue multi-chips are investigated. With Si-MEMS technology, wafer-level packaged LEDs are useful for the high power applications such as back light unit (BLU) and general solid state lighting due to the compactness and integrated fabrication process. In this paper, thermal characteristics of wafer-level packaged white LEDs with multi-chips are investigated using both serial and matrix measurement methods.
We proposed a novel linearization technique for DFB LD in Radio-over-Fiber. The proposed scheme is using light
injection based on cross-gain modulation (XGM) effect. We experimentally demonstrated and evaluated the enhanced
CNR performance using the proposed scheme.
A novel Optical network unit based on self-seeded RSOA for WDM-PON was proposed. The RSOA was self-seeded by amplified spontaneous emission of itself using fiber Bragg grating (FBG) without additional optical source.
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