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.

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 $2.85 \mathit{\mu }{\mathrm{m}}^2$ at 1550 nm, which yields an effective nonlinearity $\sim 15$ 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 $\sim 6 \mathrm{dB}$ under a forward single-pump scheme, and the Raman gain coefficient was experimentally estimated to be $7.6\times {10}^{-14} \mathrm{m}/\mathrm{W}$. Also, an 11-dB signal extinction ratio in a Raman-induced all-optical modulation experiment was achieved with the same fiber.

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.

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 $2.85 \mathit{\mu }{\mathrm{m}}^2$, we obtain a threshold of 125 mW and a slope efficiency of $\sim 70\%$. 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.

An abrupt tapered fiber In-Line Mach-Zehnder Interferometer sensor for simultaneous measurement of temperature and curvature is proposed and experimentally demonstrated. The sensor head is fabricated by arcing Corning SMF-28 using a commercial arc fusion splicer. The individual parameters discrimination was achieved by manipulating the unequal sensitivities of optical power to temperature and curvature obtained at two wavelengths within the sensing spectrum. The curvature and temperature sensitivities at λ1 (1537 nm) and λ2 (1568.7 nm) were found to be 11.8264 dBm/m⁻¹, 12.4885 dBm/m⁻¹ and 0.0829 dBm/°C, 0.0833 dBm/°C, respectively. The experimental results show unperturbed readings with rms deviation of ±0.1801 m⁻¹ and ±0.0826 °C, for curvature and temperature measurements, respectively, through measurement of optical power response of the sensor. With this simultaneous sensing technique, the proposed sensor can be deployed for many field applications such as nondestructive structural health monitoring of civil infrastructure.