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Abstract: This paper presents a multi-functional all-optical device performs simultaneous chromatic dispersion (CD) monitoring, extinction ratio (ER) improvement and tunable wavelength conversion using four-wave mixing (FWM) in a single piece of highly nonlinear optical fiber (HNLF). The multi-functional ability arises from the nonlinear power transfer function (PTF) between the input signal and the output idler wave, which not only maps the CD information of the signal onto the average power of idler wave, but also transfers the data information to the idler wave with ER enhancement, making the device compact and cost effective. Furthermore within the wavelength tuning range the monitoring sensitivity and output ER can be much higher compared to all optical monitors and regenerators proposed before. Numerical simulations are then used to demonstrate the efficiency of this method. [Copyright &y& Elsevier]

Abstract: A microstructured polymer optical fiber (mPOF) with both ultra-flattened near-zero chromatic dispersion and high birefringence based on Topas cyclic olefin copolymer is designed. Three rings of uniform elliptical air holes are arranged in triangular lattice in the cladding and an extra small defected hole is introduced in the fiber core. Guided modes, dispersion, birefringence and mode confinement properties of the designed mPOF are investigated by using the full-vector finite element method. Dispersion values between ±0.5ps/km/nm over the wavelength 1.1–1.7μm and high birefringence of the order of 10−3 are obtained for the optimized fiber structure. Low confinement losses and small effective mode area are obtained at the same time. The relatively simple architecture of the proposed Topas mPOF can be fabricated by our extrusion-stretching techniques. [Copyright &y& Elsevier]

Abstract: We introduce a new measurement method of the nonlinear coefficient (NC) of a highly nonlinear fiber based on a four-wave mixing (FWM) technique. The NC along with the fiber''s zero-dispersion wavelength (ZDW) was determined from the precise measurement of the pump power dependent optimum pump frequency for peak FWM signal generation conditions. The measurement errors of the NC and ZDW values determined with this method were less than 4.6% and 0.051nm, respectively. [Copyright &y& Elsevier]

Abstract: We investigate the dispersion property of space filling mode of photonic crystal structures and find a new type of dispersion—structure induced dispersion. By incorporating this new source of dispersion we designed PCF with large normal dispersion ~350ps2/km. Our simulation indicates the dispersion of such fiber changes less than 3% in 1.4–1.7μm wavelength range and we also show that our design is insensitive to the structure changes. [Copyright &y& Elsevier]

Abstract: A triple sampling method to have enabled excellent channel uniformity and high in-band energy efficiency is firstly proposed for the design of an ultrahigh-channel-count fiber Bragg grating (FBG), which is based on the simultaneous utilization of two amplitude-assisted phase sampling (AAPS) functions and a phase-only sampling (POS) function. As an example, one linearly chirped FBG with consecutive 1215 channels enabling to cover all fiber telecom bands (O+E+S+C+L+U) is numerically demonstrated, which has a length of 9cm, a dispersion of −1360ps/nm, and a channel spacing of 50GHz. The maximum index-change required for 10dB strength of the FBG is less than 6×10−3. [Copyright &y& Elsevier]

Abstract: A multiwavelength actively mode-locked fiber ring laser that utilises a single semiconductor optical amplifier as both a gain and mode-locking element is presented. It is verified experimentally that the number of mode-locked wavelengths may be maximised by compensating for the anomalous intra-cavity dispersion. This is achieved through the inclusion of an appropriate length of normal dispersion fiber in the laser cavity. Using this technique, the number of wavelengths simultaneously mode-locked at 10GHz was increased from 2 to 5. [Copyright &y& Elsevier]