This paper presents a novel technique to improve the design and implementation of in-fiber components by providing real time control of cladding removal by either polishing or etching. Cladding removal allows interaction between external materials and devices, and the light propagating in the fiber. Monitoring of the cladding removal process is achieved by observing the output from a section of fiber into which laser light has been focused. Resulting output graphs show that each specific fiber produces characteristic oscillations dependent on the number of modes propagating, the thickness of the cladding, the birefringence of the fiber, and the initial polarization state of the light. These oscillations result from changes in the effective indices of refraction of different modes as the cladding is removed. Electron micrographs of etched fiber surfaces show that unless proper cleaning and handling techniques are followed, the etched surface is scarred and pitted, leaving a poor quality substrate for device applications. However, if careful cleaning techniques and buffered hydrofluonc acid are used, the presence of these defects is drastically reduced and the resulting surface is smooth on a sub-micron scale. In order to understand better the characteristics of etched or polished fibers we have extended existing theoretical models which predict the effect of cladding removal on fiber birefnngence. Corroboration and use of these models allow more reliable monitoring and control of variables in the etching or polishing process such as cladding thickness, fiber alignment, acid concentration and temperature, and indices ofrefraction from fiber to fiber. Using the techniques presented in this paper, diffraction gratings are fabricated in etched D-type fibers. Other possible applications for this work include the production of variable wave plates, mode discriminators, polarizers, and the placement of detection and signal conditioning devices directly on the surface of a fiber.

It is well known that single mode and polarization maintaining fiber couplers are strategic comoonents An both communication and sensor app1 icat ions. We present here an automatic unit capable to produce fused single mode and polarization maintaining fiber couplers having a high degree of splitting ratio reproducibility and stability against environment variations. The development of the couplers production takes origin from the ac- tivities pertaining to fiber optic interferometric sensors (gy- ruscopes and hydrophones).

A distributed fiber optic temperature sensing system was developed which consisted of a high-resolution optical time domain reflectometer (OTOR) and a special optical fiber sensor. Several 1 kilometer lengths of prototype sensing fibers were formed by coating a modified, ultraviolet light curable polymer cladding material onto a core glass during fiber production. By monitoring changes in Rayleigh backscattered light from the fiber; local temperature changes were measured along the fiber length. A demonstration system was assembled with a 20 meter sensing fiber and extensive data were collected. These measurements indicated that hot spots as small as 10 cm could be detected over a temperature range of 0 to 150°C with a measurement accuracy of ±°C

This paper describes architecture and performance of a fiber op- tic gyro based on a closed loop configuration, and an integrated optic device associated with a fused type polarization preserving fiber coupler. Experimental results for open loop and closed loop operation are reported, with reference to behaviour under thermal stress condition. The 1.0. chip project methods are described ,reporting also the optical performance of the device and the inherent problems. At last general systemistic considerations and prospects of in- dustrial solution of the problems still open are given.

The double crucible with 20 nozzles contains two separate concentric crucibles with 20 nozzles on the bottom of each. Upper-side crucible is used to melt core glass and bottom-side crucible to melt cladding glass. There is a space between the two crucibles. Nozzles are welded on the bottom of each crucible. They are formed into 20 couples correspondingly and each couple of nozzles are assembled in the manner of transition fit. In order to get even thickness of cladding the tolerances between each couple of nozzles should be controlled minus 0.025mm along the direction of axis of each nozzle. The bulk glass ( F-13 and N-2 ) is heated in crucibles until it is soft enough to flow through the nozzles and meet together just on the end of nozzles. Then it is drawn directly onto a cylindrical drum of approprite diameter. Considering the fluctuate of the fiber diameter caused by the variation of temperature in crucibles and hight of the melted glass, two premelting chambers were designed. After bulk glass is melted in the premelting chambers, the melted glass flows through a hole into the double crucible. The flow should be stable and even if the diameter of the hole has been chosen correctly.

There are three know-hows in the drawing of plastic optical fibers with 36 nozzle die head: the design of 36 nozzle die head, the synchronous coating of 36 filaments and the 36 filament forming technology. The most difficult problem to be solved in the drawing of plastic optical fiber with 36 nozzle die head is the design of 36 nozzle die head. In other words, the die head has direct influence on the drawing process. The second important know-how is the techniques of synchronous coating of 36 filaments because the even extent of the cladding (coating), the state of the core-cladding intersurface and the thickness of the cladding have direct influence on the transmittance of the plastic optical fibers, too. Careful design of the drawing procedure is another important know-how in the manufacturing of plastic optical fibers. To use the 36 nozzle die head to manufacture plastic optical fibers, not only the efficiency of production can be highly increased and the cost can be largely decreased, but also the technology makes it much easier for us to produce plastic optical fiber's light guide and image guide directly.

Finite difference and finite element methods, and the coupled mode theory are combined to study in detail the ion-exchanged glass channel waveguides. Ordinary and grating assisted waveguides are analyzed. The effect of various device parameters on waveguide behavior is investigated. Design curves to make waveguides with required characteristics are provided.

An integrated optic consisting of buried diffraction gratings and a planar waveguide was developed as an internal reflectance element for broad-band spectroscopic analysis of liquids. Polystyrene or tantalum pentoxide waveguides were deposited over a pair of diffraction gratings etched into the surface of a glass slide. Multiwavelength light was focused through the substrate onto the first grating. Component wavelengths were coupled into the waveguide and spatially dispersed by the second grating after propagating through the waveguide. A silicon photodiode array detector was used to collect the spectral data. Our goal is to produce a compact, rapid spectrometer having no moving parts that can take advantage of fiber optics and fast array detectors in the visible and near-infrared regions for industrial process control. The thin planar waveguide provides enhanced sensitivity to analyze weaker absorptions in the near-infrared.

We report the first electro-optic switching device compatible with multimode fibers. A 1-to-many cascaded reconfigurable interconnection was built. A thin glass substrate was used as the guiding medium which provides not only higher coupling efficiency from multi-mode fiber to waveguide but also better tolerance of phase matching conditions. Involvement of a TIR hologram and multi-mode waveguide eliminates interface problems between fibers and waveguides. The DCG holographic material has proven to be reliable from -180°C to +200°C. Survivability of such an electro-optic system in harsh environments is further ensured. LiNbO3 was chosen as the E-O material becuase of its stability at high temperatures (phase transition temperature >1000°C) and maturity of E-O device technology. Further theoretical calculation was conducted to provide the optimal interaction length and device cpacitance.

Cesium, potassium and silver ion-exchange processes in three commercially available soda-lime and Nd-doped glasses are investigated for waveguide fabrication. A spin-coating technique is employed to make Er- and Nd-doped phosphate layers on the waveguides in soda-lirne glass. Transmission, absorption and emission properties of the waveguides are studied. Optical amplification in Nd-doped waveguides is demonstrated.

We present the electrical behavior of an integrated waveguide/photodetector based on the absorption of the evanescent optical field in an absorbing layer, deposited on the top of the waveguiding layer. We establish the expression of the electron-hole pair generation rate, for such a device. Then, we apply this result to the calculation of the dynamic quantum efficiency of an integrated waveguide/PIN-photodiode. The static and dynamic behaviors of GaInAs PIN-photodiodes monolithically integrated on a classical n/nt InP homostructure waveguide or on a GaInAsP/InP heterostructure waveguide are discussed and optimized structures are pointed out.

The development process resulting in a pulsed thick film IR emitter is described. Various configurations are discussed, including resistor and substrate variations, as well as packaging limitations. Test results are reported that indicate failure mechanisms overcome, including high current density and high temperature, as well as material migration and resistor degradation. Mechanical constraints and design configurations are also discussed. Current emitter design allows modulated operation from 500°C to 600°C at 40 to 100 Hz for periods in excess of 10,000 hours. Test results on newer materials indicate that peak temperatures and modulations twice that are feasible. Other potential applications are discussed.

In this paper an attempt is made to study the influence of photon energy on the photoernission from nonlinear optical materials from ultrathin films, cj,uantum well wires, quantum dots of the said material on the basis of a new dispersion law considerir all types of anisotropies of the band parameters within the framework of E' formalism. We have studied the photoeriisson from bulk specimens and also under the influence of an arbitrarily oriented quanti zing magne tic field in the same material tak ing n-C dGeAs as an example for the purpose of numerical computations. It is found that the photoemission increases with increasing carrier concentration non- linearly in all, the cases an oscillates with inverse magnetic field. The photoemission also increases with the incident photon energy, in a ladder like manner and exhibits oscillatory dependen- ces with Changirg film thickness in all types of quantum confine- ment. The well known results of three-band Kane model, two-band Kane model and that of parabolic model of nonlinear optical mate- rials have been obtained as special cases of our generalized theoretical formulations. The mathematical analysis is in agree- ment with the experimental observation as reported elsewhere.

Mode locking of a laterally UV prelonized discharge XeC1 laser has been obtained by using a phase conjugate mirror as full reflector in the laser cavity. The phase conjugate mirror via stimulated Brilbum scattering presents a time dependent reflectivity. It acts as a modulator and provides amplitude modulation at the cavity round trip time. An output beam made of 5 short pulses separated by 10 nsec has been obtained. The shortest pulse is 2 nsec FWHM long.

Photorefractive gain is measured in poled, 1% tantalum-doped Potassium Niobate (KNbO3). Two-wave mixing experiments are presented which exploit the '42 coefficient of KNbO3 by employing non-symmetric geometries which rotate the grating vector away from the optic axis. The effect of this rotation on the exponential gain coefficient is shown. Experimental results are compared to an analytic expression derived for this parameter. The experiments were performed using an Argon laser stabilized at =51 4.5 nm. The light was extraordinarily polarized and ihe beams were incident on the b-face of the crystal. The absorption and the response time of the crystal were measured. Losses due to scattering and self-pumped phase conjugation were also investigated.

The focusing of a neutral atomic beam using near-resonant laser light is considered. The results of a path integral solution to the Schrodinger in the stationary phase approximation are presented. The details of the derivation of the propagation kernel are presented elsewhere [1]. This approach is general and allows us to deal with "thick" laser lenses. Numerical results for the focusing of a Gaussian atomic beam are presented. These results show that spot diameters on the order of 20 Angstroms are obtainable for many reasonable choices of laser and atomic beam parameters, and that for most of these cases the thin lens approximation is not valid.

The quality of solder joints on printed circuit board (PCB) is directly related to the reliablity and stablity of electronic products. How to ensure the quality of solder joints? One necessary step in production is the inspection of defective solder joints. In this paper, an automatic holographic interferential inspection method on PCB solder joints is presented. Based on this method, the inspection system ,which includes three parts -- Optic imaging system(OIS), Automatic control system(ACS) and Processing and recognition system(PRS), has also been discussed. A series of interferential fringe image processing algorithms are put forward and discussed at the end of the paper.

The dynamical behaviours of an intracavity modulating laser with feedback device are discussed in this paper. Some of modulating methodes, such as electro-optic, acousto-optic and magneto-optic modulation etc., are introduced, and the outputs of that laser are analysed in detail, which show that output could be multistability, instability and chaos.

Both cat and ring self-pumped phase conjuqators have been realized in Ce--doped potassium niobate (KNSBN) crystals at 632 8nm by using lie-Ne laser The phase wit ies of 4(J% and 50% were measured respectively Some characteristics of the were studied experimentally barium strontium conjugate reflecti- phase conjuqaturs

The process of growing large diameter and lower residual infrared absorption single crystals of Al203:T13+ by a new growth technique named induction field up- shift method (IFSM) is described, and some of the problems in producing high laser quality single crystal are discussed using different techniques have been given.

The authors developed a high-performance magnetic and optical complex sensor unit used for applications requiring high security, such as discrimination of notes, cards, etc. This new sensor unit has a sensor head constructed of a magnetic head and a reflective-type photo sensor embedded in a small gap of the magnetic head. And enables correct pattern recognition by optical information obtained together with conventional magnetic information. Traveling this sensor head in contact with the surface of the subject of discrimination can detect difference of reflectance at the same time as the magnetic detection at the same point of place. As a result it became possible to discriminate for example, bills of any size in any country.

The field of melrology always seeks increasingly accurate, high resolution absolute measurement devices having a fast frequency response. This has driven the field of linear position measurement to accept compromises to achieve the one most desired feature for a particular task at the expense of the other features. These compromises usually take the form of trading speed and/or absolute position information for accuracy with incremental position information; or trading accuracy and/or speed for absolute position information . To try and eliminate these compromises, an absolute linear position encoder was built using a linear C.C.D., a small high-intensity area infra-red light source, a new simple absolute scale, and a digital signal processor (for image processing, temperature compensation, and calibration compensation). The prototype encoder has a measurement distance of 500 mm, and a measurement resolution of 1.0 im at measurement update rate of 1 kHz or 0.1 jtm at 15.6 Hz. The mechanical backlash or short term repeatability of the device was found to be a total of 1 pm. This device was then calibrated and checked with respect to an Hewlett Packard 5528A laser interferometer. The encoder proved to be accurate to within 5.0 tm over the 500 mm length or to have more than 16 bits of accuracy. It is clear that this new type of absolute linear position measurement technology eliminates many of the above mentioned compromises of the past by combining relatively high speed, high resolution, high accuracy, temperature compensation, and absolute position information in one measurement system.

A hybrid intensified CCI) tube, based on a moulded thinned backside-bombarded CC'!) sensor (604x288 pixels) has been achieved for applications of very low light level imaging and twodimensional photon counting. The CCD is a modiflcd version of the Philips NXA 101 1 FT sensor, moulded in a ceramic/glass material before thinning, so that the sensitive area remains flat, frontside supported and thermally stahilized. Materials are fully compatible with ultra-vacuum technological constraints and with the presence of alkalis incorporated during the photocathodc growing process. In this paper, the main results of electron detection experiments with thinned CCI)'s are displayed, both obtained in scaled tubes and in a Scanning Electron Microscope (SEM) equipment : electronic gain vs incident energy, gain fluctuations and noise behaviours, pulse height distributions under multielectron bombardment, and image homogeneity. In SEM, at 20 keV and at room temperature, the signal to noise is so high that it is possible to count up to 6 electrons in a single pixel. Thanks to the realization of stable tube prototypes, we have Used such a device in a photocounting astronomical experiment.

Sun Angle Sensors are components of satellite attitude control systems. Here we will discuss the design, fabrication, testing and performance of a 2 axis sensor with .001° resolution over a field of view.

Scanning laser beam semiconductor panel can be used for conversion of millimeter waves to visual displays. For this easy and direct method of conversion, the behavior of semiconductor panel under scanning laser beam is required. Formulas for excess carriers due to moving spot of light have beam obtained. Using these formulas single path total field attenuation through semiconductor panel for scanning laser light spot excitation as a function of scanning velocity, position and laser beam width are studied.

Reflectivity of cascaded gratings with phase-shifts is studied. It is shown that this structure has wavelength tunability. The effects of phase shift, length of different stages of the gratings, total length of grating for two and three cascaded grating stages on tunability are studied in this paper.

In this paper a general theory for a class of phase retrieval problems of two dimensional band limitted objects has been developed. A modified form of polynomial di- 1Tision algorithm is used to solve problem. A new algorithms for latent reference point problem is considered and its extension to cases in which reference point can move in object plane is also considered. In order to do this shear interfernnetric method is used. A new algorithm for sloving the problem with rectangular object has also been developed.