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A pitch-by-pitch grating inscription method that allows both high laser intensity and long-exposure dosage when inscribing each pitch is demonstrated. Based on slit beam-profiling, proposed scheme does not require oil-immersion-based beam distortion compensation techniques for inscription into free-standing single-mode fiber. High grating fringe visibility inscription is achieved for 1.07μm-period structure in single-mode fiber even though each grating pitch are individually defined by 50msec-long laser exposure.

Selective infiltration of air holes in photonic crystal fibers (PCFs) with functional materials can equip optical fiber devices with advanced functions. We propose a new method which enables precise selective infiltration of dual-core PCF (DC-PCF) by using femtosecond laser micromachining. Through this proposed technique, we have successfully selective infiltrated single air hole with a diameter of 2.5μm inside a DC-PCF. This method is simple, precise and repeatable, and it provides great potential for fabricating advanced fiber devices using selective infiltration technique.

A low cost and CMOS-process compatible solution capable of passive-alignment coupling of singlemode optical fiber (SMF) to silicon-on-insulator (SOI) based photonic waveguide (size: sub-μm) is critical for realization and acceptance of fiber-pigtailed SOI-based electronics/photonics integrated circuits (EPIC) chips for mass applications in optical interconnects, optical information processing and sensing. In this work, we propose and demonstrate monolithic integration of an ultra-compact Si/SiO 2 multilayer super-high numerical-aperture (NA) graded-index (MLS-GRIN) lens mode-size converter on SOI-based waveguide platform. The MLS-GRIN lens, with longitudinal focal-length of 20μm, total stack height of 8μm, and simulated NA better than 3, converts optical mode size vertically from SMF (core-φ ∼9μm) to 300nm-thick SOI waveguide by an engineered near-parabolic refractive index profile formed by varying the thickness ratio of alternating Si/SiO 2 layers, while keeping the thicknesses of Si and SiO 2 less than quarter of optical wavelength in the medium. The horizontal mode size conversion is performed by lateral up-taper of Si-waveguide prior to MLS-GRIN lens on the chip.

We propose a novel technique based on Fourier analysis and perturbation theory to describe completely the step discontinuity in a slab waveguide of any index contrast without the need for analytical approximations or assumptions. Through this technique, we derive a spectral overlapping criterion and a coupling matrix that analyzes effectively the roles of the radiation modes in the resultant computation accuracy. A symmetric nano-waveguide with 55.9% index contrast is investigated under normal incident light condition along TE polarization. The total reflectance and the guided power reflectivity are computed at the waveguide-air interface. Results obtained are consistent with the FDTD simulation and only requires very short computational time.

The capabilities of the Dynamic Thermal Electron Quantum Medium FDTD (DTEQM-FDTD) model in simulating semiconductor media and devices are illustrated. Both transient and steady-state carrier dynamics, along with associated physical phenomena are obtained. Using the same computational model, the operational dynamics of a Fabry-Perot laser cavity are further illustrated.

The dynamic thermal electron quantum medium FDTD (DTEQM-FDTD) model is used to demonstrate ultrafast carrier dynamics in saturable gain and absorber media. The same model is then used to simulate a passive mode locked laser.

A 1.2(height)times125(depth)times500(length) micro-slot was engraved along a fiber Bragg grating by chemically assisted femtosecond laser processing. By filling epoxy and UV-curing, waveguide with plastic-core and silica-cladding was created, presenting high thermal responding coefficient of 211pm/degC.

A novel superimposed fiber Bragg grating (FBG) structure with polarization-discriminating characteristics is demonstrated. By superimposing the FBGs onto a tilted fiber grating, simultaneous wavelength- and polarization-filtering are achieved and are tailored purely by grating parameters.

A bidirectional nonreciprocal wavelength-interleaving filter based on an optically coherent high birefringence fiber transversal filter structure is demonstrated. Stable, low loss operation is achieved with reconfigurable transfer characteristics for interleaved channel spacing of 0.8 nm with >30 dB isolation and ultra-low chromatic dispersion.

A simple technique based on superimposed cavities structure for direct real-time assessment of a DFB fiber laser mode condition during operation is demonstrated and used to provide a cavity mode conditioning feedback mechanism to optimize output performance. Significant improvements to the output performance and robustness are achieved over the entire pump power range without ambient isolation.

A novel dual complementary output optical fiber transversal filter is realized for DWDM applications. Stable, simultaneous complementary filter responses with flattened passbands and large sidelobe suppressions are achieved with a single-line cascaded Hi-Bi fiber structure.

Differential group delay measurement of narrowband fiber devices using a fiber polarization scrambler with a modulation phase shift technique is demonstrated. Accurate measurement is realized with high wavelength and delay resolution and immunity to environmental perturbation.

Optical generation of a millimetre wave signal based on a co-located, dual distributed feedback fibre laser structure is proposed and demonstrated. Through the use of high birefringence fibre grating for polarization-discriminating self-injection feedback, the fibre laser produces stable dual polarization mode operation. Due to high common-mode suppression of phase noise, a millimetre wave beat signal of high spectral purity is obtained. Experimental result illustrates a heterodyne signal measured at /spl sim/32.5 GHz with a linewidth of

A novel all-fiber bipolar delay line filter is realized in a single-line cascaded high birefringence fiber structure. Optically coherent operation is achieved with suppression of interference noise. Complementary filter outputs give simultaneous lowpass and highpass responses.