Optical fibers and waveguides designed for broadband infrared transmission, spanning approximately 1 micron to over 20 microns, have historically faced challenges such as high cost, brittleness, environmental susceptibility, and fragility, limiting their widespread practical use. In this paper, we introduce a new approach utilizing molten-core fiber manufacturing to create silver halide cores. The core composition shows improved broadband transmission, ranging from 0.6 micron to over 25 microns. Additionally, we report the fabrication of isotropic silver halide material with reduced crystalline scattering. The optical measurements and structural analysis of halide core material suggest the pathway for lower-loss infrared fibers and components with directly laser-written plasmonic structures.
In this effort we report the new Ship Relative Instant Multispectral Positioning System for rapid initialization and real-time acquisition of relative pose for navigation inputs to the flight control system based on infrared multispectral guidance and novel electro-optic sensors with the goal of meeting the challenging Navy requirements for fully automated landing of the fixed wing aircraft on an aircraft carrier. The selection of eye safe infrared wavelength band around 1.5 microns for the system operation minimizes the risks for the pilots, maximizes signal-to-noise ratio due to lower solar background, expands the system reach due to lower scattering in the atmosphere and allows for the overall system cost reduction due to the use of readily available components from developed industry of optical communications. The feasibility of rapidly initializing detection, tracking and relative pose estimation through concept modeling and breadboard prototype testing will be presented.
The sustainable orbital manufacturing with commercially viable and profitable operation has tremendous potential for driving the space exploration industry and human expansion into outer space. This highly challenging task has never been accomplished before. The current relatively high delivery cost of materials represents the business challenge of value proposition for making products in space. FOMS Inc. team identified an opportunity of fluoride optical fiber manufacturing in space that can lead to the first commercial production on orbit. To address continued cost effective International Space Station (ISS) operations FOMS Inc. has developed and demonstrated for the first time a fully operational space facility for orbital remote manufacturing with up to 50 km fiber fabrication capability and strong commercial potential for manufacturing operations on board the ISS.
We present the new precision optical navigation guidance system approach that provides continuous, high quality range and bearing data to fixed wing aircraft during landing approach to an aircraft carrier. The system uses infrared optical communications to measure range between ship and aircraft with accuracy and precision better than 1 meter at ranges more than 7.5 km. The innovative receiver design measures bearing from aircraft to ship with accuracy and precision better than 0.5 mRad. The system provides real-time range and bearing updates to multiple aircraft at rates up to several kHz, and duplex data transmission between ship and aircraft.
The single aperture implementation of laser radars in combination with beam scanning solutions enables low cost, compact and efficient laser systems for 3D acquisition. The design benefits include the lack of dead zones, improved stability and compact footprint for the system implementation. In our presentation we focus on the scanning solution development for 3D laser radars that is based on all solid state magneto-optic design. The novel solid-state scanner implementation results are presented.
Single aperture range finders with eye safe lasers due to their smaller size and simplified design have a strong potential for wide implementation in military and commercial systems. In this paper we present the results of experimental evaluation of a single aperture laser range finder. The new design operates at eye safe wavelength range around 1535 nm and uses passively Q switched laser for illumination. The optical circulator is used to separate the detection and illumination channels. The measurements of the power budget and ranging performance evaluation for the new design are discussed.
The design considerations for low cost, shock resistant, compact and efficient laser radars and ranging systems are discussed. The reviewed approach with single optical aperture allows reducing the size, weight and power of the system. Additional design benefits include improved stability, reliability and rigidity of the overall system. The proposed modular architecture provides simplified way of varying the performance parameters of the range finder product family by selecting the sets of specific illumination and detection modules. The performance operation challenges are presented. The implementation of non-reciprocal optical elements is considered. The cross talk between illumination and detection channels for single aperture design is reviewed. 3D imaging capability for the ranging applications is considered. The simplified assembly and testing process for single aperture range finders that allows to mass produce the design are discussed. The eye safety of the range finder operation is summarized.
Fluorozirconate glasses, such as ZBLAN (ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF ), have the potential for optical transmission from 0.3 μm in the ultraviolet to 7 μm in the infrared regions. However, crystallites formed during the fiber-drawing process prevent this glass from achieving its desired transmission range. The temperature at which the glass can be drawn into a fiber is known as the working range, defined as (Tx-Tg), bounded by the glass transition temperature (Tg) and the crystallization temperature (Tx). In contrast to silica glasses, the working temperature range for ZBLAN glass is extremely narrow. Multiple ZBLAN samples were subjected to a heating and quenching test apparatus on the parabolic aircraft under a controlled μ-g and hyper-g environments and compared with 1-g ground tests. Optical microscopy examination elucidates that crystal growth in ZBLAN is suppressed and initiates at a later temperature when processed in a microgravity environment. Thus, the crystallization temperature, Tx, at which the crystals form has increased. The glass transition temperature, Tg, remains constant, as crystallization does not occur until approximately 360°C for this composition of ZBLAN. Therefore, the working temperature range for ZBLAN has been broadened.
Fluorozirconate glasses, such as ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF), have the potential for optical transmission from 0.3 μm in the UV to 7 μm in the IR region. However, crystallites formed during the fiber drawing process prevent this glass from achieving its desired transmission range. The temperature at which the glass can be drawn into a fiber is known as the working range, defined as (Tx - Tg), bounded by the glass transition temperature (Tg) and the crystallization temperature (Tx). In contrast to silica glasses, the working temperature range for ZBLAN glass is extremely narrow. Multiple ZBLAN samples were subject to a heating and quenching test apparatus on the parabolic aircraft, under a controlled 0-g and hyper-g environment and compared with 1-g ground tests. The microgravity duration on board Zero-G Corporation parabolic aircraft is approximately 20 seconds and the hyper-g intervals are approximately 56 seconds. Optical microscopy examination elucidates crystal growth in ZBLAN is suppressed when processed in a microgravity environment. The crystallization temperature, Tx, at which crystals form increased, therefore, significantly broadening the working temperature range for ZBLAN.
Physical Optics Corporation (POC) presents a novel Mobile ELISA-based Pathogen Detection system that is based on a
disposable microfluidic chip for multiple-threat detection and a highly sensitive portable microfluidic fluorescence
measurement unit that also controls the flow of samples and reagents through the microfluidic channels of the chip. The
fluorescence detection subsystem is composed of a commercial 635-nm diode laser, an avalanche photodiode (APD) that
measures fluorescence, and three filtering mirrors that provide more than 100 dB of excitation line suppression in the
signal detection channel. Special techniques to suppress the fluorescence and scattering background allow optimizing the
dynamic range for a compact package. Concentrations below 100 ng/mL can be reliably identified. The entire instrument
is powered using a USB port of a notebook PC and operates as a plug-and-play human-interface device, resulting in a
truly peripheral biosensor. The operation of the system is fully automated, with minimal user intervention through the
detection process. The resolved challenges of the design and implementation are presented in detail in this publication.
For the first time, a >10W single-mode Tm-doped amplifier is demonstrated. The all fiber format is optimized for single frequency signals in the 1800 - 2020 nm band. Natural Tm 3+ gain bandwidth is shifted towards the 1800nm and 2000nm region by selecting the fiber composition and length. No SBS-related issues were observed at levels of >10W of output power while using a single-frequency seed source. A simple model allowing the prediction of amplifier gain is presented.
Fiber Bragg gratings are used in a wide variety of devices including sensors, tunable filters, and signal controllers for Wavelength Division Multiplexing. Bragg gratings can be formed in an optical fiber by illuminating the fiber from the side with a pattern of ultraviolet light. Most gratings are made using 240-nm light. However, by using 330-nm light the grating can be written right through the standard polymer coating of the fiber, which preserves the fiber's mechanical strength. We discuss some of the mechanisms that degrade the strength of fiber gratings. We also discuss applications of mechanically strong fiber gratings, including very wide (> 50 nm) tunable filters.
Optical fiber sensors (OFSs) offer numerous advantages, which include immunity to electromagnetic interference, intrinsic safety, small size, a possibly high sensitivity, multiplexing capabilities, and the possibility of remote interrogation. However, OFSs have a relatively low penetration in the commercial market, which is still dominated by standard electromechanical sensors. Nuclear environments are an example where particular OFSs might have a distinct superiority in the competition, but the feasibility of using OFSs in radiation environments still needs to be assessed. In the present paper we report on irradiation experiments performed to provide a sound basis for the design of a fiber Bragg grating based sensor capable to operate even under high total dose exposure.
Generation of picosecond pulses at two distinct wavelengths is interesting for wavelength-division-multiplexing, fiber communication and sensing. For this purpose, we achieved harmonic active mode locking simultaneously at two wavelengths separated by about 15 m in an Erbium-doped fiber laser. Dual- wavelength lasing was obtained with two wide-bandwidth (greater than 1 nm) nonchirped high-reflectivity fiber Bragg gratings inserted in the laser cavity. The fiber Bragg gratings were written with 275-nm light from an Ar laser in hydrogen-loaded fibers. Optical path lengths and losses were carefully adjusted at each wavelength to obtain perfect mode locking at both wavelengths. Total cavity dispersion was set in the anomalous dispersion regime and optimized at each wavelength independently to generate solitons. Pulses at 3-GHz repetition rate were obtained at two wavelengths simultaneously with pulse widths of 16 ps and 13 ps, at 1547 nm and 1562 nm respectively. Time-bandwidth products of 0.37 and 0.34 respectively confirmed that the pulses were nearly transform-limited at each wavelength.
Many different schemes of Bragg grating based quasi-distributed and multiplexed sensors have been reported.1 Most of them utilize wavelength division multiplexing and detect the resonant wavelength for sensor interrogation
The influence of titanium and lead dopants on the waveguide fabrication by ion exchange process and photoinduced second harmonic generation has been investigated. The similar effect of the glass composition on photoinduced second order nonlinearity and refractive index increment by ion exchange has been observed. The obtained results made it possible to rule out the influence of the glass structure on the charge transfer processes in lead silicate glasses.
We report for the first time the refractive index grating side-writing in 10 mol.% GeO2-doped fiber by near-UV light of cw Ar+-laser (333 - 364 nm). The magnitude of induced index change as large as 1.9 multiplied by 10-4 at 1.7 multiplied by 105 W/cm2 UV power density has been achieved. The observed gratings have exhibited the same temperature stability as gratings written by KrF excimer laser (248 nm).
The effect of hydrogen loading on near-UV photosensitivity of germanosilicate glass is studied. The enhanced bleaching of 390 nm luminescence band and 240 nm absorption band, as well as enhanced growth of 650 nm luminescence band in hydrogen loaded samples is observed. The increase of paramagnetic GeE' defects concentration and creation of hydrogen related paramagnetic H(II) centers is obtained. Long period index gratings with low insertion loss and index change as large as 4 multiplied by 10-4 are fabricated by near-UV argon laser radiation in hydrogen loaded fibers. The effect of gamma irradiation on the properties of the fabricated gratings is reported.
Photoinduced second harmonic generation in titanium and cerium doped lead-silicate glasses at different infrared preparation intensities is reported. The influence of dopants on second harmonic conversion efficiency is discussed.
The photosensitivity of germanium-doped silica glass fibers and related phenomena, namely photoinduced second harmonic generation and refractive index change, attract considerable interest. In the present paper the microscopic mechanisms of the photosensitivity, which are based on photoionization and structural transformation, are considered. The recent experimental results, which reveal the role of excited triplet state of germanium oxygen deficient defect in the photosensitivity of germanium-doped glass, are discussed.
We report experimental studies of photoinduced second-harmonic generation (SHG) in lead glasses with different PbO concentrations. The dependencies of photoinduced second-harmonic saturation efficiency on PbO concentration and calculated third-order nonlinearity are observed. The optical concentration of PbO for photoinduced SHG is found to be approximately 50 wt%. Experimental results are interpreted on the base of photovoltaic model.
KEYWORDS: Lead glass, Semiconductors, Photovoltaics, Glasses, Second-harmonic generation, Microcrystalline materials, Near field optics, Near field, Solar energy, Harmonic generation
Evidence for different microscopic mechanisms of coherent photovoltaic effect in lead glass and semiconductor microcrystallite-doped glass is obtained by temperature studies of photoinduced second harmonic generation.
Photonic Applications for Aerospace, Transportation, and Harsh Environment III
23 April 2012 | Baltimore, Maryland, United States
Course Instructor
SC260: Fiber Gratings for WDM Applications
Fiber gratings are widely used as spectrally selective components in modern fiber optic links with Wavelength Division Multiplexing (WDM). The design, fabrication, performance and reliability of Bragg and long-period fiber gratings for fiber optic networks are covered in this course. The applications of fiber gratings for channel management and monitoring, dispersion control and gain equalization are discussed in detail.
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