The historical beginnings of photosensitivity and fiber Bragg grating (FBG) technology are recounted. The basic techniques for fiber grating fabrication, their characteristics, and the fundamental properties of fiber gratings are described. The many applications of fiber grating technology are tabulated, and some selected applications are briefly described.

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Fiber Bragg grating technology fundamentals and overview

In-fibre Bragg grating (FBG) sensors are one of the most exciting developments in the field of optical fibre sensors in recent years. Compared with conventional fibre-optic sensors, FBG sensors have a number of distinguishing advantages. Significant progress has been made in applications to strain and temperature measurements. FBG sensors prove to be one of the most promising candidates for fibre-optic smart structures. This article presents a comprehensive and systematic overview of FBG sensor technology regarding many aspects including sensing principles, properties, fabrication, interrogation and multiplexing of FBG sensors. It is anticipated that FBG sensor systems will be commercialized and widely applied in practice in the near future due to the maturity of economical production of FBGs and the availability of cost effective interrogation and multiplexing techniques.

https://iopscience.iop.org/article/10.1088/0957-0233/8/4/002/pdf

In-fibre Bragg grating sensors

Erbium doped materials are of great interest in thin film integrated optoelectronic technology, due to their Er3+ intra-4f emission at 1.54 μm, a standard telecommunication wavelength. Er-doped dielectric thin films can be used to fabricate planar optical amplifiers or lasers that can be integrated with other devices on the same chip. Semiconductors, such as silicon, can also be doped with erbium. In this case the Er may be excited through optically or electrically generated charge carriers. Er-doped Si light-emitting diodes may find applications in Si-based optoelectronic circuits. In this article, the synthesis, characterization, and application of several different Er-doped thin film photonic materials is described. It focuses on oxide glasses (pure SiO2, phosphosilicate, borosilicate, and soda-lime glasses), ceramic thin films (Al2O3, Y2O3, LiNbO3), and amorphous and crystalline silicon, all doped with Er by ion implantation. MeV ion implantation is a technique that is ideally suited to dope these materials with Er as the ion range corresponds to the typical micron dimensions of these optical materials. The role of implantation defects, the effect of annealing, concentration dependent effects, and optical activation are discussed and compared for the various materials.

Erbium implanted thin film photonic materials

Recent developments in rare-earth doped materials for optoelectronics

The intensive investment in optical microelectromechanical systems (MEMS) in the last decade has led to many successful components that satisfy the requirements of lightwave communication networks. In this paper, we review the current state of the art of MEMS devices and subsystems for lightwave communication applications. Depending on the design, these components can either be broadband (wavelength independent) or wavelength selective. Broadband devices include optical switches, crossconnects, optical attenuators, and data modulators, while wavelength-selective components encompass wavelength add/drop multiplexers, wavelength-selective switches and crossconnects, spectral equalizers, dispersion compensators, spectrometers, and tunable lasers. Integration of MEMS and planar lightwave circuits, microresonators, and photonic crystals could lead to further reduction in size and cost

/pdf/optical-mems-for-lightwave-communication-53kgmfd364.pdf

Optical MEMS for Lightwave Communication

We describe a silica-based 16/spl times/16 strictly nonblocking thermooptic matrix switch with a low loss and a high extinction ratio. This matrix switch, which employs a double Mach-Zehnder interferometer (MZI) switching unit and a matrix arrangement to reduce the total waveguide length, is fabricated with 0.75% refractive index difference waveguides on a 6-in silicon wafer using silica-based planar lightwave circuit (PLC) technology. We obtained an average insertion loss of 6.6 dB and an average extinction ratio of 53 dB in the worst polarization case. The operating wavelength bandwidth completely covers the gain band of practical erbium-doped fiber amplifiers (EDFAs). The total power consumption needed for operation is reduced to 17 W by employing a phase-trimming technique which eliminates the phase-error in the interferometer switching unit.

Low loss and high extinction ratio strictly nonblocking 16/spl times/16 thermooptic matrix switch on 6-in wafer using silica-based planar lightwave circuit technology

A low-loss and high-extinction-ratio silica-based 16/spl times/16 thermooptic matrix switch is demonstrated. The switch, which employs a double Mach-Zehnder interferometer switching unit and a matrix arrangement which reduces the total waveguide length, is fabricated with 0.75% refractive index difference waveguides on a 6-in silicon wafer. The average insertion loss and the average extinction ratio are 6.6 and 55 dB, respectively. The total power consumption is 17 W.

Low-loss and high-extinction-ratio silica-based strictly nonblocking 16/spl times/16 thermooptic matrix switch

A high gain of 27 dB is achieved in an erbium-doped silica-based planar waveguide amplifier integrated with a directional coupler which multiplexes the signal and pump light. A low noise figure of 5.0 dB is attained with the planar amplifier by using an integrated coupler which is formed of erbium-doped silica-based waveguides.

Erbium-doped silica-based waveguide amplifier integrated with a 980/1530 nm WDM coupler

An Er-doped waveguide amplifier fabricated by plasma enhanced chemical vapour deposition is described. A maximum net gain of 5 dB and a gain coefficient of 0.67 dB/cm are obtained in a 0.48 wt% Er-doped waveguide pumped at 420 mW at a wavelength of 0.98 μm. The 0 dB gain threshold is 23 mW.

Erbium-doped phosphosilicate glass waveguide amplifier fabricated by PECVD

Irradiation of hydrogen loaded or flame brushed phosphorus doped, germanium free silica glass with a 193‐nm ArF excimer laser changes the optical absorption at ultraviolet wavelengths by 40–140 dB/mm and the refractive index by more than 2×10−4 Bragg gratings with 90%–95% reflectivity are photoinduced in channel optical waveguides made from this glass The thermal stability of the photosensitivity is measured by annealing up to 700 °C

K. Hattori

Papers

Low loss and high extinction ratio strictly nonblocking 16/spl times/16 thermooptic matrix switch on 6-in wafer using silica-based planar lightwave circuit technology

Low-loss and high-extinction-ratio silica-based strictly nonblocking 16/spl times/16 thermooptic matrix switch

Erbium-doped silica-based waveguide amplifier integrated with a 980/1530 nm WDM coupler

Erbium-doped phosphosilicate glass waveguide amplifier fabricated by PECVD

Photosensitivity in phosphorus‐doped silica glass and optical waveguides