http://w3.uqo.ca/photonique/papers/Highly%20Sensitive%20Bend%20Sensor%20with%20Hybrid%20Long%20Period%20and%20Tilted%20Fiber%20Bragg%20Grating.pdf

Highly sensitive bend sensor with hybrid long-period and tilted fiber Bragg grating

We report the first (to our knowledge) development of a Bi/Er/Al/P codoped germanosilica optical fiber showing ultrabroadband luminescence between 1000 and 1570 nm, covering O-, E-, S-, C-, and L-bands, when pumped by 532, 808, or 980 nm lasers. The fluorescence profiles are found highly pump wavelength dependent, closely associated with different combinations of excitations from both Bi centers and Er ions as active centers. With a proper selection of pump wavelength(s), this Bi/Er codoped fiber could be used as an ultrabroadband gain medium for ultrabroadband amplified spontaneous emission sources, fiber lasers, or amplifiers in telecommunications and in other fields.

Bismuth and erbium codoped optical fiber with ultrabroadband luminescence across O-, E-, S-, C-, and L-bands.

An LPP EUV light source is disclosed having an optic positioned in the plasma chamber for reflecting EUV light generated therein and a laser input window For this aspect, the EUV light source may be configured to expose the optic to a gaseous etchant pressure for optic cleaning while the window is exposed to a lower gaseous etchant pressure to avoid window coating deterioration In another aspect, an EUV light source may comprise a target material positionable along a beam path to participate in a first interaction with light on the beam path; an optical amplifier; and at least one optic directing photons scattered from the first interaction into the optical amplifier to produce a laser beam on the beam path for a subsequent interaction with the target material to produce an EUV light emitting plasma

Drive laser delivery systems for euv light source

A fiber-optic curvature sensor based on a core offset single-mode fiber (SMF) combined with a fiber Bragg grating (FBG) is presented. The FBG cladding modes are efficiently excited by the large core misalignment. The curvature of the fiber can be obtained by the ratio between the recoupled cladding mode power and the reflected core mode power. These measurements are independent from temperature variation.

/pdf/temperature-independent-curvature-sensor-using-fbg-cladding-51t28b68vp.pdf

Temperature-Independent Curvature Sensor Using FBG Cladding Modes Based on a Core Misaligned Splice

This paper presents a review of the development of optical fibers made of multiple materials, particularly including silica glass, soft glass, polymers, hydrogels, biomaterials, Polydimethylsiloxane (PDMS), and Polyperfluoro-Butenylvinyleth (CYTOP). The properties of the materials are discussed according to their various applications. Typical fabrication techniques for specialty optical fibers based on these materials are introduced, which are mainly focused on extrusion, drilling, and stacking methods depending on the materials’ thermal properties. Microstructures render multiple functions of optical fibers and bring more flexibility in fiber design and device fabrication. In particular, micro-structured optical fibers made from different types of materials are reviewed. The sensing capability of optical fibers enables smart monitoring. Widely used techniques to develop fiber sensors, i.e., fiber Bragg grating and interferometry, are discussed in terms of sensing principles and fabrication methods. Lastly, sensing applications in oil/gas, optofluidics, and particularly healthcare monitoring using specialty optical fibers are demonstrated. In comparison with conventional silica-glass single-mode fiber, state-of-the-art specialty optical fibers provide promising prospects in sensing applications due to flexible choices in materials and microstructures.

https://www.mdpi.com/2304-6732/6/2/48/pdf

Multifunctional Smart Optical Fibers: Materials, Fabrication, and Sensing Applications

We investigate new types of mode recouplings in a concatenated grating structure comprising a long-period grating and a fiber Bragg grating. It is demonstrated that the light coupled out to the cladding mode by one of these gratings can be recoupled back to the guided mode by the other grating. Theoretical analysis based on the coupled-mode theory is presented, together with experimental results.

/pdf/cladding-mode-assisted-recouplings-in-concatenated-long-21typmcsce.pdf

Cladding-mode-assisted recouplings in concatenated long-period and fiber Bragg gratings

Error-free all-optical packet switching is demonstrated by use of a multiwavelength mutual injection-locked Fabry-Perot laser diode. A 10-Gbit/s data signal is switched on and off with an extinction ratio of 16.9 dB when an optical control signal is turned off and on with a power difference of only 3 dB.

/pdf/demonstration-of-an-all-optical-switch-by-use-of-a-1nvsofdfo2.pdf

Demonstration of an all-optical switch by use of a multiwavelength mutual injection-locked laser diode.

Multiwavelength fiber lasers based on multimode fiber Bragg gratings using offset launch technique

A method of controlling the state of polarization of an optical signal includes injecting the optical signal into a laser diode and matching the wavelength of the optical signal to a longitudinal mode of the laser diode. A stabilizer signal can also be injected in to the laser diode. The wavelength of the stabilizer signal is matched a first longitudinal mode of the laser diode a longitudinal mode of the laser diode to the optical signal.

/pdf/method-and-apparatus-for-controlling-the-polarization-of-an-2cxeh4o0oz.pdf

Method and apparatus for controlling the polarization of an optical signal

Recent developments of Bismuth-based erbium-doped fibers (Bi-EDFs) have demonstrated their potential applications for broadband amplifiers, particularly for the L-band in DWDM systems, for short pulse amplifiers to be used in very high bit-rate transmission systems (up to 160 Gbps), and for ultra wideband tunable fiber ring lasers. The low concentration quenching of erbium ions in Bi-based glass permits efficient high erbium concentration Bi-EDFs (up to 26,000 ppm) to be fabricated allowing the realization of ultra-short length erbium-doped fibre amplifiers and fiber lasers. In this paper, we reported the performance of two Bi-EDFs with different erbium ions concentrations for signal amplification. One fiber was doped with 6,470 wt-ppm of erbium ions and the other was doped with 3,250 wt-ppm of erbium ions. The performance of a 253-cm long Lanthanum co-doped Bi-based EDF (3,250 ppm of erbium) for the amplification of 142 wavelength channels was evaluated. 140 of the input signals were located at the 50-GHz ITU grid. Signal gains of over 20 dB and NF less than 6.7 dB were measured for all the channels with wavelengths ranging from 1554.13 nm to 1612.22 nm (i.e. over 58 nm). 3-dB bandwidth of 53.9 nm and quantum conversion efficiency of about 60 % were attained when the fiber was pumped with 350 mW and 623 mW of pump power, respectively. The performance of an ultra-short length Bi-EDFA, using 23-cm of Bi-EDF doped with 6,500 ppm of erbium ions pumped at 980 nm, for the amplification of picosecond pulses will be discussed. The results of an ultra wideband (106 nm) tunable fiber ring laser based on the higher erbium concentration Bi-EDF will also be presented.

Weng Hong Chung

Papers

Cladding-mode-assisted recouplings in concatenated long-period and fiber Bragg gratings

Demonstration of an all-optical switch by use of a multiwavelength mutual injection-locked laser diode.

Multiwavelength fiber lasers based on multimode fiber Bragg gratings using offset launch technique

Method and apparatus for controlling the polarization of an optical signal

Development of Bi2O3-based erbium-doped fibers