Z. Yusoff

Four-wave mixing based 10-Gb/s tunable wavelength conversion using a holey fiber with a high SBS threshold

We demonstrate a four-wave-mixing based wavelength converter using a 15-m highly nonlinear holey fiber (HF) with a high stimulated Brillouin scattering (SBS) threshold. Error-free efficient wavelength conversion of 10-Gb/s nonreturn-to-zero signal over a /spl sim/10-nm bandwidth is reliably achieved. Our 15-m HF has a nonlinearity coefficient /spl gamma//spl sim/70(/spl plusmn/10) W/sup -1//spl middot/km/sup -1/ and an SBS threshold of more than 130 mW. The high SBS threshold is achieved by applying structural variation to the HF along its length during the fabrication process. No modulational-instability-induced intensity noise on the converted signals is observed due to the normal dispersion of the HF.

Raman effects in a highly nonlinear holey fiber: amplification and modulation

We experimentally demonstrate that a short length of highly nonlinear holey fiber (HF) can be used for strong L(+) -band (1610-1640-nm) Raman amplification and ultrafast signal modulation. We use a pure silica HF with an effective area of just 2.85mum(2) at 1550 nm, which yields an effective nonlinearity ~15 times higher than in conventional silica dispersion-shifted fiber. Using a 75-m length of this fiber, we obtained internal Raman gains of more than 42 dB and a noise figure of ~6 dB under a forward single-pump scheme, and the Raman gain coefficient was experimentally estimated to be 7.6 chi 10(-14)m/W . Also, an 11-dB signal extinction ratio in a Raman-induced all-optical modulation experiment was achieved with the same fiber.

A holey fiber-based nonlinear thresholding device for optical CDMA receiver performance enhancement

We demonstrate the use of an optical thresholder based on a short length of holey fiber to achieve enhanced code recognition quality in a 255-chip 320-Gchip/s superstructured fiber Bragg grating-based optical code-division multiple access code:decode system. The nonlinear thresholder is based on bandpass filtering of spectrally broadened components generated by self-phase modulation and assisted by the Raman effect in an 8.7 m length of highly nonlinear holey fiber. Error free penalty free system performance is obtained with complete recovery of the original input pulse shape.

A tunable WDM wavelength converter based on cross-phase modulation effects in normal dispersion holey fiber

We demonstrate a tunable wavelength-division-multiplexing wavelength converter based on cross-phase modulation in just 5.8 m of highly nonlinear normal dispersion holey fiber (HF) and incorporating a precise compression-tuned apodized fiber-grating filter. We achieve both error-free and penalty-free 10-Gb/s wavelength conversion over a /spl sim/15-nm bandwidth. The short device length and correspondingly reduced pulse walkoff effect ensures a constant wavelength-converted signal pulsewidth across the full tuning range. The use of HF with normal dispersion eliminates the coherence-degradation related intensity noise previously observed in experiments employing anomalously dispersive HF.

Investigation of Brillouin effects in small-core holey optical fiber: lasing and scattering

We demonstrate for what is believed to be the first time a Brillouin laser based on a holey fiber (HF). Using a simple Fabry-Perot resonator scheme containing a 73.5-m-long highly nonlinear HF with an effective area of 2.85 microm(2) , we obtain a threshold of 125 mW and a slope efficiency of ~70% . Stimulated and spontaneous Brillouin scattering effects are investigated in the HF, and we show that the high lasing threshold is due mainly to reduction of the effective gain coefficient caused by structural nonuniformity along the fiber length.

A 36-channel x 10-GHz spectrally sliced pulse source based on supercontinuum generation in normally dispersive highly nonlinear holey fiber

We demonstrate a spectrally sliced pulse source which utilizes supercontinuum generated in a normally dispersive holey fiber and spectral slicing in an arrayed waveguide grating. All 36 10-GHz channels exhibit almost constant pulsewidth and excellent noise properties, as verified by bit-error-rate measurements.

High nonlinearity extruded single-mode holey optical fibers

We report the fabrication of the first microstructured single-mode non-silica glass fiber from an extruded preform. The measured effective nonlinearity (/spl gamma/) is 550 W/sup -1/ km/sup -1/, more than 500 times larger than standard silica fiber.

Widely tunable multi-wavelength Brillouinerbium fiber laser utilizing low SBS threshold photonic crystal fiber.

A widely tunable low stimulated Brillouin scattering (SBS) photonic crystal fiber (PCF) based multi-wavelength Brillouin-erbium fiber laser is presented. The fiber laser structure utilizes a pre-amplified Brillouin pump (BP) technique with 100 m of PCF and a tunable band-pass filter within a Fabry-Perot cavity. A total of 14 Brillouin Stokes lines can be tuned over 29 nm from 1540 nm to 1569 nm. The wide tunability was only limited by the bandwidth of the tunable band-pass filter. A constant channel spacing of 0.079 nm and signal to noise ratio (SNR) of more than 20 dB for each Brillouin Stokes lines were also observed.

Spacing-Switchable Multiwavelength Fiber Laser Based on Nonlinear Polarization Rotation and Brillouin Scattering in Photonic Crystal Fiber

A new spacing-switchable multiwavelength erbium-doped fiber laser (EDFL) is demonstrated using switchable nonlinear polarization rotation (NPR) and stimulated Brillouin scattering (SBS) effects. The laser employs a 100-m-long photonic crystal fiber in conjunction with a four-port circulator in a figure-of-eight arrangement to provide the intensity-dependent transmission effect, as well as to discriminate the even-order and odd-order Brillouin Stokes to have a double-frequency Brillouin Stokes output. Without the Brillouin pump (BP), the laser operates in an NPR mode to produce at least 22 lasing wavelengths with a side mode suppression ratio of more than 10 dB and a wavelength spacing of 0.27 nm. In the Brillouin erbium fiber laser mode, at least 30 Brillouin lines with a spacing of 0.16 nm are obtained at BP power of 3 dBm and 980-nm pump power of 120 mW.

Nonlinear tapered holey fibers with high stimulated Brillouin scattering threshold and controlled dispersion

We numerically calculate optical property maps for hexagonally arranged nonlinear holey fibers made of silica, lead silicate, and bismuth oxide-based glass and employ them to design tapered fibers with enhanced stimulated Brillouin scattering threshold and a simultaneous control of the average dispersion.