We describe the applicability of photonic crystal fiber (PCF) with an enlarged effective area Aeff to a distributed Raman amplification (DRA) transmission. We investigate the DRA transmission performance numerically over a large Aeff PCF taking account of the signal-to-noise ratio (SNR) improvement RSNR in the S, C, and L bands. We show that an RSNR of 3 dB can be expected by utilizing DRA with a maximum pump power of 500 mW when the Aeff of the PCF is 230 µm2.

The characteristics of hole-assisted fiber (HAF) are investigated both numerically and experimentally in terms of its applicability as a bending-loss insensitive fiber (BIF). We show that HAF with the desired mode-field diameter (MFD), bending-loss and cutoff wavelength characteristics can be roughly designed by taking a few specific structural parameters into consideration. We also show that an optical cord composed of adequately designed HAF realizes satisfactory transmission performance with respect to its multi-path interference (MPI) characteristics. These results reveal that a hole-assisted type BIF will be beneficial for realizing easy and economical installation and maintenance in future access networks.

We investigate numerically the applicability of photonic crystal fiber (PCF) with a uniform air hole structure as a wide-band transmission medium. We show that accumulated dispersion over the PCF can be reduced effectively by optimizing the index profile of dispersion compensating fiber (DCF). We also show that a bandwidth of more than 300 nm will be available for 40 Gbit/s NRZ transmission by using the PCF as a transmission medium instead of conventional 1.3 µm zero-dispersion single-mode fiber (SMF).