A Study of 16-Channel Optical Demultiplexer for DWDM with Liquid Crystal Enabled Functionalities
| Autor: | Yi-Fan Lai, 賴奕帆 |
|---|---|
| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 92 We have designed and demonstrated a liquid-crystal-based 16-channel tunable optical DEMUX and Optical Demultiplexer feedback control Pixel Equalizer. It consists of EDFA, a collimating lens, grazing-incident grating, image lens, a transmission-type liquid crystal spatial light modulator (LC-SLM), fiber array for output, OSA, photodetector, and digital variable resistor, and computer. In this system, first-order diffracted signal light by the grating is directed to the image lens and focused on to the LC-SLM and fiber array. Selecting the appropriate LC-SLM pixels allows light of the desired wavelength to transmit into the fiber array. The center wavelengths of the channels are designed and the channels are designed according to the International Telecommunication Union (ITU) grid with channel spacing of 100 GHz. The crosstalk between channels is less than –30 dB. The average 1 dB and 3 dB passbands of the DEMUX are 12.5 and 22.5 GHz, respectively. The center wavelength of each channel is accurate to 0.04 nm. The extinction ratios for pixels on/off for the 16 channels range from 11.1 dB to 16.2 dB. The average extinction ratio is 13.53 dB. The outputs of the channels of the LC-multi-DEMUX are equalized to –65 dBm and the variation between different channels are reduced from ~10 dB to less than 0.5 dB. We have demonstrated optical demultiplexer feedback control pixel equalizer to reduce ripple level and easy to control of LC-multi-DEMUX. We selected four channels to feedback control the power level, the fluctuation is reduced to 1.2% or 0.052dB. We can modulate the transmittance of LC-SLM to adapt to the different conditions and change the each channel power easily independently by PC. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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