Improved flatness and tunable bandwidth of the supercontinuum generation in all-normal dispersion-flattened PCF using Littman-Metcalf optical bandpass filter
- 作者：Qi Jing ; johnsonyiqi@gmail.com ; Xia zhang ; Huifang Ma ; Yongqing Huang ; Xiaomin Ren
- 关键词：Supercontinuum ; Littman&ndash ; Metcalf optical bandpass filter ; Flatness improvement
- 刊名：Optics and Laser Technology
- 出版年：2012
- 期刊代码：48_00303992
- 类别：ph
- 出版时间：September, 2012
- 卷：44
- 期：6
- 页码：1660-1669
- 文件大小：2512 K
摘要
We have proved that in an all-normal dispersion-flattened photonic crystal fiber (PCF), the four-wave mixing (FWM) process dominantly affects the flatness of the generated supercontinuum (SC). The numerical results show that pulses with steepened edges can enhance the FWM conversion efficiency during the SC鈥檚 generation and the minima of the spectral oscillatory structure will be smoothed. A double-pass Littman-Metcalf optical bandpass filter is used to make the 1.60 ps hyperbolic-Secant shaped pulses obtain steepened edges. The experimental results show that the flatness of the SC generated from the 4 nm filtered pulses is improved by 0.21 dB. The SC with 10-65 nm tunable bandwidths is obtained by adjusting the filter bandwidth from 1 nm to 7 nm. Further numerical results show that the filter induced SC鈥檚 flatness improvement is more effective for pulses with 2.0-4.0 ps FWHM. The improved SC can be used for applications which require stable modulation carriers and flexible bandwidth.