Highly thermally responsive hybrid in-fiber slab waveguide grating structure with a plastic core and a silica cladding

A 1.2(height)×125(depth)×500(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/°C.

Fiber Bragg grating structures inscribed using 800nm femtosecond laser in single- and multi-core mid-IR glass fibers with their spectral, thermal and strain properties

Single- and multi-core passive and active germanate and tellurite glass fibers represent a new class of fiber host for in-fiber photonics devices and applications in mid-IR wavelength range, which are in increasing demand. Fiber Bragg grating (FBG) structures have been proven as one of the most functional in-fiber devices and have been mass-produced in silicate fibers by UV-inscription for almost countless laser and sensor applications. However, because of the strong UV absorption in germanate and tellurite fibers, FBG structures cannot be produced by UVinscription. In recent years femtosecond (fs) lasers have been developed for laser machining and microstructuring in a variety of glass fibers and planar substrates. A number of papers have been reported on fabrication of FBGs and long-period gratings in optical fibers and also on the photosensitivity mechanism using 800nm fs lasers. In this paper, we demonstrate for the first time the fabrication of FBG structures created in passive and active single- and three-core germanate and tellurite glass fibers by using 800nm fs-inscription and phase mask technique. With a fs peak power intensity in the order of 1011W/cm2, the FBG spectra with 2nd and 3rd order resonances at 1540nm and 1033nm in a single-core germanate glass fiber and 2nd order resonances between ~1694nm and ~1677nm with strengths up to 14dB in all three cores of three-core passive and active tellurite fibers were observed. Thermal and strain properties of the FBGs made in these mid-IR glass fibers were characterized, showing an average temperature responsivity of ~20pm/°C and a strain sensitivity of 1.219±0.003pm/µe.

Highly thermally responsive hybrid in-fiber sSlab waveguide grating structure with a plastic core and a silica cladding

A 1.2(height)×125(depth)×500(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/°C.

Directional bend sensor based on an asymmetric modification of the fiber cladding by femtosecond laser

A femtosecond laser was used to modify a part of the cladding of a standard LPG bend sensor. The device produced wavelength shifts depending upon the direction of bend, thus making a shape sensor. © 2005 Optical Society of America.

Novel optical chemsonsor based on etched D-fiber bragg gratings

A novel optical chemsensor concept based on the cladding etched Bragg gratings in D-fiber is demonstrated. Two etched devices have been used to measure the concentrations of sugar solution, giving sensitivity as high as 0.02nm/%.

Phase synchronization of a two-channel phase-sensitive amplifier based on optical injection-locking of InP quantum-dash mode-locked lasers

A synchronization scheme for a two-channel phase sensitive amplifier is implemented based on the injection-locking of single InP quantum-dash mode-locked laser. Error free performance with penalty <1 dB is demonstrated for both channels. © 2011 Optical Society of America.

Design of a fiber scheme for nonlinear Raman pump broadening through modulation instability

In this work we explore numerically an experimentally the dependence of the broadened spectra on the choice of fibers and we analyze a series of basic rules to be taken into account when using nonlinear broadening to reduce the gain ripple of broadband Raman amplifiers

Simple design of nonuniform fiber Bragg grating with sharp reflection

In this paper we consider the possibility of using intermediate solutions, in which ideal apodisation profile for a dispersion-free, sharp-reflection profile fibre Bragg grating approximated in different degrees. The ideal apodisation profile for a flat dispersion, 50 GHz bandwidth grating was obtained using the layer-peeling algorithm. To verify the modelled results a version of the 5-section grating has been manufactured with excellent agreement between the model and the experimental results. The performance penalty due to multiple reflections from the FBGs in different situations was studied. The results showed that in the approximated gratings some post-compensation must be included to account for the local deviations from zero dispersion. © 2003 IEEE.

A nonreciprocal wavelength-interleaving bidirectional coherent fiber transversal filter

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.

Optimization of DFB fiber laser performance based on a superimposed cavities structure

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 for DWDM applications

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.

Accurate differential group delay measurement of narrowband fiber devices with immunity to environmental perturbation

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.

Suppression of cladding-mode coupling loss in Bragg grating using standard single-mode fiber

We present a technique for suppressing cladding-mode coupling loss in fiber Bragg grating fabrication. Suppression of cladding-modes down to 0.2 dB in a Bragg grating of 18dB reflectivity has been achieved in hydrogen-loaded standard single-mode fiber.

Optimal power budget in quasi-linear dispersion-managed fiber links

We develop a theory of an optimal distribution of the gain of in-line amplifiers in dispersion-managed transmission systems. As an example of the application of the general method we propose a design of the line with periodically imbalanced in-line amplification.