Abstract: An object of the present invention is to provide a device that performs dispersive compensation in an optical fiber transmission path, such as performing waveform shaping in optical fiber transmission. This adaptive dispersion compensating element is provided with a chirp Bragg grating 104 formed in an optical fiber, a temperature gradient impressing means 105 that impresses a temperature gradient along the longitudinal direction of the chirp Bragg grating, a spectral resolving means 106 that spectrally resolves the output light from the chirp Bragg grating, a detecting means 107 that detects the output light from the spectral resolving means, and a control means 108 that performs feedback control of the temperature gradient impressing means based on the output from the detecting means and provides a compact and high-stability device that performs the dispersive compensation in the optical fiber transmission path, such as performing the waveform shaping in the optical fiber transmission.

Abstract: A system for fabricating Bragg gratings includes an optical waveguide (e.g., an optical fiber, a planar waveguide), an interference pattern generator (e.g., a transmission phase grating such as a phase mask or a diffraction grating), first motion equipment (e.g. a nanostage), a pulsed light source (e.g. an excimer laser), and second motion equipment (e.g. a stepper motor). A method for fabricating Bragg gratings using this system includes providing relative motion between the optical waveguide and the interference pattern using the nanostage, providing relative motion in discrete increments between the pulsed light source and the assemblage comprising the optical waveguide, nanostage, and interference pattern generator using the stepper motor, and successively exposing the optical waveguide to the pulsed light through the interference pattern generator when the optical waveguide and interference pattern are effectively stationary relative to the pulsed light.

Abstract: A wavelength division multiplexer/demultiplexer (WDM) for use in an optical network has a structure for holding at least one optical component. A diffraction grating assembly having a substrate is held in relation to the at least one optical component by the structure. A lens assembly having a focal length is held in relation to the at least one optical component. The grating assembly has an angular dispersion that changes with temperature and the product of the focal length and angular dispersion remains constant over temperature.

Abstract: A temperature compensated optical device includes a compression-tuned glass element 10 having a Bragg grating 12 therein, a compensating material spacer 26 and an end cap 28 all held within an outer shell 30. The element 10, end cap 28 and shell 30 are made of a material having a low coefficient of thermal expansion (CTE), e.g., silica, quartz, etc. and the spacer 26 is made of a material having a higher CTE, e.g., metal, Pyrex®, ceramic, etc. The material and length L5 of the spacer 26 is selected to offset the upward grating wavelength shift due to temperature. As temperature rises, the spacer 26 expands faster than the silica structure causing a compressive strain to be exerted on the element 10, which shifts the wavelength of the grating 12 down to balance the intrinsic temperature induces wavelength shift up. As a result, the grating 12 wavelength is substantially unchanged over a wide temperature range.

Abstract: Electrically switchable optical elements, such as application specific integrated elements including filters, lenses and switches, are combined with wavelength locked feedback loops. Electrically Switchable Bragg Grating (ESBG) technology is combined with a wavelength locked feedback loop to provide variable focal length optical systems which automatically adjust the focal length of incident light.

Abstract: In accordance with an exemplary embodiment of the present invention, a method of forming at least one layer over an optical element includes providing the optical fiber which has a central axis; rotating the optical element about the central axis; and forming the layer with a substantially uniform thickness during the rotation.

Abstract: A compact and easily manufacturable waveguide optical frequency router (10) is provided. The router (10) has a transmit core region (12) and a plurality of receive core regions (14) formed within a slab region (18). The router (10) further includes an array of distributed Bragg deflectors (DBDs) (16) formed within the core regions (12,14) for coupling optical energy (20) between the transmit core region (12) and the receive core regions (14) via the slab region (18). The array of DBDs (16) distributes the optical energy (20) between the receive core regions (14) based on optical wavelength and propagation angle.

Abstract: A system and method is described for distributing light within a light guide which is used for illuminating the user interface of an electronic device. The light guide is formed as a thin film and impressed with a pattern of input and output diffraction gratings to control the transmission of light into and out of the light guide to efficiently illuminate the user interface.

Abstract: An optical delay generator comprises a first waveguide made from electro-optically active material resonantly coupled to a second non-electro-optically active waveguide. The first waveguide contains a chirped distributed Bragg reflector structure which reflects optical signals at a specific wavelength at a specific reflection point within the structure. An electric field applied to the first waveguide changes the refractive index of the electro-optically active material and thus shifts the reflection point. Optical signals reflecting from the reflection point are resonantly coupled into the second waveguide, and are thus not affected by the electric field applied to the first waveguide. The controllable optical delay applied to the optical signals results from control over the reflection point and the round-trip travel time for an optical signal forward propagating in the first waveguide, being reflected at the reflection point, and backward propagating in the second waveguide.

Abstract: There is disclosed a method for the holographic recording of data, wherein a hologram containing the date is recorded in a waveguide layer (3). The holograms are formed in a layer structure containing multiple waveguide layers (3). Coupling means (12) are provided for selectively coupling the reference beam (11) into the single waveguide layers (3) of the layer structure. The invention also relates to an arrangement for holographic recording of data, comprising a data storage medium with a waveguide holographic storage layer, and an optical system for writing and reading the holograms. The optical system comprises means for imaging an object beam (5) and a reference beam (11) on the storage medium. The arrangement comprises multiple waveguide holographic storage layers (3) in the storage medium, and means for selectively coupling the reference beam (11) into the single waveguide layers (3) of the layer structure.

Abstract: The present invention relates to an optical filter whose a sidelobe disturbing a characteristic of an optical filter by weighting an optical coupling efficiency between waveguides is controlled upon applying a selective area growth method in a wavelength selective variable semiconductor optical filter and method of fabricating the same. The present invention can control the thickness of growth layer selectively by controlling the width of the dielectric thin film mask whose the growth is not achieved in the selective area growth method, can control the distance between two waveguides of the wavelength selective variable semiconductor optical filter by applying the result on the distance control between two waveguides. Accordingly, there can be changed an optical coupling efficiency between two waveguides spatially.

Abstract: A de-multiplexing system for optical signals including an optical fiber attached to an optical fiber taper is provided. Optical signals are transmitted through the optical fiber to the optical fiber taper. An etched diffraction grating located at the end of the optical fiber taper de-multiplexes optical signals. Bi-directional de-multiplexing can be accomplished by providing optical fiber tapers with etched diffraction gratings at both ends of the optical transmission fiber. A GRIN lens can be provided for focusing the de-multiplexed signals onto specific optical detectors.

Abstract: According to an exemplary embodiment of the present invention, an optical waveguide and method of use includes a grating which has a grating parameter that is adapted for dynamically variable non-uniform alteration. The non-uniform alteration of the grating parameter results in the introduction of a predetermined amount of chromatic dispersion and dispersion slope into an optical signal traversing the waveguide.

Abstract: A method of writing an extended grating structure in a photosensitive waveguide comprising the steps of utilising at least two overlapping beams of light to form an interference pattern, moving the waveguide through said overlapping beams, simultaneously controlling a relative phase delay between the beams utilising a phase modulator, thereby controlling the positions of maxima within said interference pattern to move at approximately the same velocity as the photosensitive waveguide, wherein the phase modulator does not comprise a mechanical means for effecting the phase modulation, and modifying the relative phase delay between the beams during the writing of the grating structure, whereby a deliberate detuning of the velocity of the positions of maxima within said interference pattern and the velocity of the photosensitive waveguide is utilised to vary a period of the written grating structure in the photosensitive waveguide.

Abstract: The present invention relates to a device and a method for wavelength selective filtration of optical wavelength channels. The wavelength selective filter (1) includes one or more wavelength selective add-drop elements (10, 12, 14 and 16) and one or more on-off switches (20, 22, 24 and 26), wherein a first and a second side of the wavelength selective add-drop elements (10, 12, 14 and 16) includes an input and an output, wherein said on-off switches (20, 22, 24 and 26) are disposed between said input and output on the second side of the wavelength-selective add-drop elements (10, 12, 14 and 16), and wherein in the event of more than one wavelength selective add-drop element said elements are interconnected by means of a connecting waveguide between respective outputs and inputs on the first side of respective wavelength selective add-drop elements.

Abstract: A surface-emitting device has a substrate and a light-emitting device section formed on the substrate, and emits light in a direction intersecting the substrate. The light-emitting device section includes a light-emitting layer, an anode and cathode for applying an electrical field to the light-emitting layer, and a grating.

Abstract: A method and an electro-optical device are presented for affecting the propagation of input light impinging on the device. The electro-optical device is composed of at least one domain-patterned ferroelectric crystal structure with inverted domains, and an electrodes' arrangement on the surface of the at least one structure connected to a voltage source.

Abstract: An add/drop filter for optical wave energy incorporates a Bragg grating in a very narrow waist region defined by merged lengths of elongated optical fibers. Light is propagated into the waist region via adiabatically tapered fibers and is transformed from two longitudinally adjacent fibers into two orthogonal modes within the air-glass waveguide of the waist and reflected off the grating from one fiber into the other. The geometry of the waist region is such that the reflected drop wavelength is polarization independent, without lossy peaks in the wavelength band of interest. Additionally, back reflection are shifted out of the wavelength band of interest. High strength gratings are written by photosensitizing the waist region fibers by constantly in-diffusing pressurized hydrogen or deuterium. For narrow spectral bandwidth gratings, dimensional variations must be minimized or compensated, and the grating is apodized by both a.c. and d.c. variations in writing beams at a net constant power.

Abstract: Variable optical filter, at least consisting of an optical filter structure (2) with different zones (3A-3B-3C-3D-3E) and/or reflection surfaces (4A-4B-4C-4D-4E-4F) which are made such that light (L1) with a well-defined wavelength passes, whereas light (L2) with another wavelength is reflected, in particular according to the so-called Bragg principle, whereby this filter (1-1A-1B-1C) also is provided with means (7) for altering the optical characteristics of the filter structure (2), characterized in that the aforementioned means (7) at least consist in that, on one hand, the optical path of the aforementioned filter structure (2) comprises a portion (6) based on one or more polymers, which is configured as an optical cavity enclosed by refractive surfaces of the aforementioned filter structure, and the optical characteristics of which can be changed under the influence of an electric potential, an electric field (E), respectively, or under the influence of light and, on the other hand, the filter (1) is pro

Abstract: This invention relates to a number of components, devices and networks involving integrated optics and/or half coupler technology, all of which involve the use of electronically switchable Bragg grating devices and device geometries realized using holographic polymer/dispersed liquid crystal materials. Most of the components and devices are particularly adapted for use in wavelength division multiplexing (WDM) systems and in particular for use in switchable add/drop filtering (SADF) and wavelength selective crossconnect. Attenuators, outcouplers and a variety of other devices are also provided.

Abstract: An integrated-optic device comprising a photorefractive substrate, an optical waveguide channel and at least one diffractive Bragg grating integrated in the substrate and intersecting the optical waveguide channel. The diffractive Bragg grating(s) causes at least a fraction of light coupled into the optical waveguide channel to be coupled out of the optical waveguide channel.

Abstract: A method, systems and apparatus for providing true-time-delayed signals using optical inputs is disclosed. In one aspect a system for providing optical true-time-delayed signals is provided. The system includes at least one optical source having emitting an optical signal having a predetermined wavelength, an optical waveguide optically coupled to the at least one optical source, and a diffraction element optically coupled to the waveguide, the diffraction element positioned along the waveguide at a predetermined distance.

Abstract: Techniques for designing efficient gratings with multiple frequency response channels based on sampled patterns based predominantly on phase modulation of the underlying grating structure. Each period of the phase sampled patterns may include contiguous, discrete phase segments with different phase values, or alternatively, a continuous spatial phase pattern that changes the phase of the underlying grating structure. Moderate amplitude modulation of the underlying grating structure by the sampling structure may also be used together with phase modulation. The grating period or the sampling period may be chirped.

Abstract: A semiconductor-based tunable optical dispersion compensation method and apparatus for multiple channels. In one aspect of the present invention, an apparatus according to an embodiment of the present invention includes a semiconductor material. An optical path through the semiconductor material is included. The optical path is optically coupled to receive an optical beam. A nonlinearly chirped Bragg grating is disposed in the semiconductor material. The optical path includes the nonlinearly chirped Bragg grating to substantially reduce chromatic dispersion in the optical beam.

Abstract: An integrated-optic attenuator/equalizer device comprising a photorefractive substrate, at least one optical waveguide channel formed in the substrate, at least one diffractive-Bragg grating formed in the substrate, and a diffractive-Bragg grating modulator that is capable of modulating the diffractive Bragg grating(s). The diffractive-Bragg grating(s) intersects the optical waveguide channel. When a diffractive-Bragg grating formed in the substrate is modulated, at least a fraction of light of a wavelength associated with the modulated diffractive-Bragg grating is re-directed by the modulated diffractive-Bragg grating, thereby preventing the re-directed fraction of light from arriving at the output of the optical waveguide channel.

Abstract: An integrated-optic device comprising a photorefractive substrate, an optical waveguide channel and at least one diffractive Bragg grating integrated in the substrate and intersecting the optical waveguide channel. The diffractive Bragg grating(s) causes at least a fraction of light coupled into the optical waveguide channel to be coupled out of the optical waveguide channel.

Abstract: The invention concerns a tunable filter comprising an optical fiber incorporating a Bragg grating on a portion of the fiber. Said fiber portion is coated with a material retained within a confined space and adapted to exert pressure on said Bragg grating to compress said portion of fiber radially and to stretch it longitudinally.

Abstract: A process (400) to construct single- and multi-dimensional optical gratings (100, 800) of interlayers (110, 230, 310, 808) of differing refractive index, either in or atop a non-fiber substrate material (104, 202, 302). The optical gratings (100, 800) may particularly be Bragg type gratings, and thus suitable for receiving a laser beam (102, 240, 802) and forming there from one or more reflected beam portions (118, 248, 810) having one or more narrow wavelengths and a passed beam portion (120, 250, 812) of other wavelengths.

Abstract: A frequency processing system (1000, 1100, 1200, 1300) for detecting, tuning, or stabilizing light frequency or wavelength in a light beam (1012, 1112, 1212, 1312) produced by a light source (1010, 1110, 1210, 1310). A grating block (1014, 1114, 1214, 1314) receives the light beam (1012, 1112, 1212, 1312) and may produce diffracted beams (1018, 1118, 1218, 1318a-b) and a passed beam (1016, 1116, 1216, 1316). The diffracted beams (1018, 1118, 1218, 1318a-b) are received by respective detectors (1020, 1120, 1220, 1320a-b) which produce measurement signals (1022, 1122, 1322a-b) that are communicated to a processor (1024, 1124, 1224, 1324). The processor (1024, 1124, 1224, 1324) then produces control signals (1026, 1126, 1226, 1326a-b) that are communicated to the light source (1010, 1110, 1210, 1310) where they are usable for detecting, tuning, or stabilizing the light frequency or wavelength.

Abstract: A method for making an apodized Bragg grating in a photosensitive, planar, linear waveguide. A photosensitive, planar, linear waveguide is provided on a surface of a substrate. A patterned phase mask is placed between the waveguide and a laser beam. The waveguide is exposed through the phase mask to the laser beam wherein either the laser beam is moving at a substantially constant velocity with respect to the substrate and phase mask, or the substrate and phase mask are moving at a substantially constant velocity with respect to the laser beam. The beam has a smoothly varying intensity profile, and the exposure is conducted at an angle of more than 0° and less than 90° to the longitudinal axis of the waveguide under conditions sufficient to induce a modulation in the index of refraction of the waveguide and impart an apodized Bragg grating in the waveguide corresponding to the phase mask pattern.

Abstract: The invention relates to polarization mode dispersion; writing index variations in a grating written in an optical fiber generates polarization mode dispersion. The invention proposes to compensate this polarization mode dispersion by mechanical curvature of the fiber. The invention provides a simple method of compensating polarization mode dispersion effectively and improving the performance of a grating written in a fiber; it applies in particular to Bragg gratings.

Abstract: The present invention relates generally to electro-optically active waveguide segments, and more particularly to the use of a selective voltage input to control the phase, frequency and/or amplitude of a propagating wave in the waveguide. Particular device structures and methods of manufacturing are described herein.

Abstract: An optical delay generator includes a waveguide made from electro-optically active material which contains a chirped distributed Bragg reflector. An electric field generated across the waveguide causes the index of refraction within the waveguide to change. A change in the index of refraction results in a change in the point at which light is reflected from the chirped distributed Bragg reflector within the waveguide, thus providing a controllable delay for optical pulses. Optical pulse position modulation is provided by using the optical delay generator to control the delay imparted on each pulse within a stream of equally-spaced optical pulses.

Abstract: Electrically switchable optical elements, such as application specific integrated elements including filters, lenses and switches, are combined with wavelength locked feedback loops. Electrically Switchable Bragg Grating (ESBG) technology is combined with a wavelength locked feedback loop to provide variable focal length optical systems which automatically adjust the focal length of incident light.

Abstract: A position measuring system that includes a graduation support having a measuring graduation, a planar waveguide and a light source that generates light that is conducted to the measuring graduation, wherein the light is reflected at surfaces of the planar waveguide. A scanning unit for scanning the measuring graduation that includes a light-sensitive scanning area to which light modulated by the measuring graduation is conducted. The modulated light conducted to the light-sensitive scanning area has at least two different light portions, which differ in a number of reflections at the surfaces of the planar waveguide, and wherein the reflecting of the at least two different light portions occurs prior to reaching the measuring graduation.

Abstract: A flat panel display is based on a new switching technology for routing laser light among a set of optical waveguides and coupling that light toward the viewer. The switching technology is based on poled electro-optical structures. The display technology is versatile enough to cover application areas spanning the range from miniature high resolution computer displays to large screen displays for high definition television formats. The invention combines the high brightness and power efficiency inherent in visible semiconductor diode laser sources with a new waveguide electro-optical switching technology to form a dense two-dimensional addressable array of high brightness light emissive pixels.

Abstract: In accordance with the present invention, a waveguide grating comprises a core and a first cladding material adjacent the core. The first cladding is configured, as by etching, to provide a periodic grating, and a second cladding material having a controllable refractive index overlies the first cladding material. If the index of the second cladding is different from that of the first cladding, the configuration of the first cladding provides an optical grating. If, however, the controllable index of the second cladding is adjusted to equal that of the first cladding, the grating becomes essentially transparent. This grating is particularly useful as a reconfigurable add/drop filter in a WDM optical communication system. It is also useful in grating-assisted couplers and variable optical delay lines.

Abstract: Consistent with the present invention, in-fiber Bragg gratings are used to demultiplex optical signals in a WDM optical communication system. The in-fiber Bragg gratings also perform dispersion compensation of the selected optical signals. As a result, additional segments of DCF for further dispersion compensation are rendered unnecessary. Improved performance is thus achieved with an inexpensive and simplified system design.

Abstract: Conventional quadratically chirped fiber Bragg gratings are typically apodized at both their high and low chirp ends. The present specification describes an improved Bragg grating reflector in which a second quadratically chirped region is arranged in front on the high chirp end of a substantially conventional quadratically chirped portion. The high chirp end of the first portion is not apodized; instead this apodization takes place in the second portion, and so enables the first portion to exhibit appreciable reflectivity to signals having wavelengths extending to the Bragg wavelength corresponding to the high chirp end of the first portion. The present invention thus enables the useable bandwidth of a quadratically chirped grating to be increased, and so enables an increased tuning range to be achieved in adjustable dispersion (and adjustable dispersion compensation) apparatus incorporating such gratings.

Abstract: An optical structure and devices based thereon for the compensation of chromatic dispersion in a multi-channel light signal are provided. The optical structure includes a waveguide and a Bragg grating provided therein. The Bragg grating has a plurality of grating components, each associated with one or a few of the channels to be compensated. The period of each grating component is selected to allow compensation of chromatic dispersion experienced by this particular channel or these particluar channels, thereby taking into account the wavelength-dependent dispersion slope of the light signal.

Abstract: The present invention proposes optical fiber equipment having a Bragg grating tunable by a piezoelectric actuator, the equipment comprising an optical fiber, a Bragg grating photoinduced in said fiber, a support for supporting said fiber and comprising two uprights at opposite ends of said Bragg grating, each upright having a first holding element for holding said fiber, and a piezoelectric actuator held via its ends between the two uprights, said actuator being longitudinally prestressed in compression between said uprights.

Abstract: The present invention relates to a method and devices for multiplexing and demultiplexing optical signals. The present invention relates to a method and devices for integrating the multiplexer and demultiplexer functionality with the switch array. The wavelength switchable optical filter comprises an optical waveguide having a grating along a section thereof, the grating comprising a pre-selected number of spaced sub-gratings with each sub-grating having a sub-grating period, the grating has a spectral response characterized by a pre-selected number of spaced band-pass windows spanning a pre-selected wavelength range. The optical filter includes modifying means connected to the optical waveguide for modifying the sub-grating period, refractive index or a combination thereof for selectively opening or closing each of said band pass windows independently of all the other band pass windows.

Abstract: A method of establishing transmission of light through a chirped Bragg-reflector, a method of analyzing the power spectrum of a light signal using a chirped Bragg-reflector, and an arrangement for analyzing the power spectrum of a light signal. The Bragg-reflector reflects, in an unperturbed state, essentially all incident light within a predefined wavelength range. The methods include the steps of directing the light to be analyzed into an input end of a light guiding structure, such as an optical fiber, which light guiding structure is provided with a Bragg-reflector, and sending an acoustic pulse along the light guiding structure, thereby effectively lowering the reflectance of the Bragg-reflector for a certain wavelength at a certain time. By monitoring the light thus transmitted through the Bragg-reflector, a power spectrum analysis of the incident light is obtained.

Abstract: A Bragg grating that has an average index of refraction that changes with temperature to compensate for variations in grating spacing caused by temperature changes.

Abstract: An optical waveguide Bragg grating fabrication apparatus (1) comprises a light source (2) providing ultra-violet (UV) light and optical means (4,5A-B,6A-B,7A-B,9) for adapting the light beam to form an interference pattern in a photosensitive optical waveguide (8). The interference pattern has a spatial intensity modulation along the length of the optical waveguide and thus providing an optical grating in the waveguide in the form of a refractive index modulation.

Abstract: A wide variety of Fiber Bragg writing devices comprising solid state lasers are provided. The solid state lasers emit moderate peak-power output beams which are suitable for efficient production of fiber Bragg gratings without causing embrittlement of the optical waveguide. These solid state lasers generate output beams with wavelengths of approximately 240 nm, in order to match the primary absorption peak in the ultraviolet range for a typical optical waveguide. In some embodiments, the solid state lasers comprise Ti:sapphire lasers which are tuned to produce fundamental wavelengths which are frequency-multiplied. In other embodiments, the output beam of a Ti:sapphire laser is mixed with a harmonic beam from a pump laser. Some embodiments output the third harmonic of a fundamental beam.

Abstract: A diffraction-optical component for providing a radiation-diffracting grating structure is proposed, comprising a surface wave device including a substrate 43, a surface wave source 47 excitable with an adjustable frequency for producing surface waves on a surface 45 of the substrate 43 and an interaction region 17 of the substrate surface 45 which is provided for the radiation to interact with a grating structure provided by the surface waves produced.

Abstract: A method for writing a Bragg grating in a waveguide comprises the steps of placing the waveguide in a writing position in which the waveguide extends essentially along one axis; generating a beam of ultraviolet radiation; executing a first and a second scan with the said beam along the waveguide through a phase mask, in such a way as to generate interference fringes capable of modifying the refractive index along the said waveguide in a predetermined way; moving the phase mask, during the first or the second scan, with an oscillatory motion about one of its equilibrium positions and along a direction lying at an angle of less than 90° to the axis of the said waveguide, in such a way as to produce, in this scan, an essentially zero envelope of the refractive index; and varying the intensity of the energy of the ultraviolet radiation in a controlled way along the waveguide during the first and the second scan, for example by controlling the scanning velocity.

Abstract: A semiconductor-based laser tuning method and apparatus. In one aspect of the present invention, an apparatus according to an embodiment of the present invention includes a gain medium disposed in a semiconductor substrate. A laser cavity is disposed in the semiconductor substrate and is optically coupled to the gain medium. A first reflector defines one end of the laser cavity. The first reflector includes a first tunable Bragg grating disposed in the semiconductor substrate. The first tunable Bragg grating includes a first plurality of silicon and polysilicon interfaces along the semiconductor substrate such that there is a first plurality of perturbations of a refractive index along the Bragg grating. The first tunable Bragg grating selectively reflects light having a tunable center wavelength so as to emit light through stimulated emission having the tunable center wavelength in the laser cavity. A second reflector defines an other end of the laser cavity.

Abstract: Method and apparatus for polarizing light propagating in an optical fiber. The apparatus has an optical fiber having a Fiber Bragg Grating (FBG) section of predetermined length therein, and a force applying device for applying a lateral force to a predetermined portion of the FBG section. The predetermined portion comprises a predetermined percentage of the predetermined length. When the predetermined percentage is equal to or greater than about 10 percent, two polarization states for the light passing through the optical fiber are obtained. When the predetermined percentage is a small portion of the grating length, for example, about 1 percent of the length of a chirped grating, a finely tunable optical fiber polarizer is provided. The apparatus can use standard optical fiber such as telecomm fiber and provides various advantages including the capability of being switched on and off by simply applying and withdrawing the lateral force.