In this article, the performance of FBG-assisted ICI reduction is compared with that of SG with different OFDM symbol rise times and in presence of CD. Increase in symbol rise times requires the reduced intervals of a SG but the length of FBG remains same. The rise time of 5 ps and presence of delay due to CD, the BER performance of FBG is better than that of SG, especially for transmission distance above 30 km. In the case of middle subcarriers, FBG gives BER < 10 23 for 45 km. In the AO-OFDM system with FBG based passive device, synchronization between the ICIfree region and sampling instant is not needed, which omitting complex tuning circuits and reducing the system cost, and CP is not required due to tolerance to CD increases. 2. N. Cvijetic, OFDM for next generation optical access networks, J Lightwave Technol 30 (2012), 384-398. 3. D. Hillerkuss, et al., 26 Tbit s-1 line-rate super-channel transmission utilizing all-optical fast Fourier transform processing, Nat Photon 5 (2011), 364-371.

The folded multiple‐mode resonators with complementary split ring resonator (CSRR), and defected ground structures (DGS) are introduced for notched ultrawideband (UWB) bandpass filter (BPF) design in this article. Using the CSRR, FMRR, notched wide‐band BPF, a notch response can exist in the UWB passband for blocking the interference. Adjusting the size factor of CSRR, the wide tuning ranges of notch frequencies included the desired frequencies of 5.2/5.8 GHz are achieved. The lower insertion loss (0.31 dB), higher rejection level (−48.40 dB), wider bandwidth (FBW 75%), and wider stopband (extended to 2.01 f0 below −20 dB rejection level) of UWB band at the central frequency f0 = 4.58 GHz are obtained. Second, design a CSRR, DGS, FMRR, tri‐notched UWB filter, the wider bandwidth (3.1–9.8 GHz) with FBW = 126%, lower insertion loss (0.26 dB), and higher rejection level (−44 dB) of UWB band at central frequency f0 = 5.6 GHz are presented. Using the CSRR and interdigital couple, three notch responses can exist in the UWB passband for blocking the interference signals. Adjusting the size factor of CSRR and interdigital couple, the wide tuning ranges of notch frequencies included the desired frequencies of 5.18/6.10/8.08 GHz are achieved. The wide tuning ranges of three notched frequencies cover from 5.0 to 8.4 GHz. It is a simple way to control the notch responses. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:571–579, 2014.

This paper describes the development of W AOTFs for extending the wavelength range to below 250nm. Two types of W AOTFs. developed include: (a) A KDP AOTF was operated without the use of polarizers. Performance tested at 2 5 3 . 7~1 1 includes: FWHM of 0 . 8 q dfiaction efficiency of 50 percent at a drive power of 1.3W. (b) A lower power MgFz AOTF was demonstrated by using acoustic resonance enhancement. Results obtained at 1 . 9 6~1 include a FWHM of 5.5nm and a maximum diffi-action efficiency of 78 percent.

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