Abstract: An optical coupling is useful for lessening negative effects associated with launching high power signals from a single mode optical fiber. The coupling has a mono-mode optical fiber fused axially to a second optically homogeneous glass fiber having no core and no optical power, the latter fiber dimensioned such that light propagating from the optical fiber's core diverges and passes rectilinearly therethrough without touching the side walls of the second fiber. The second fiber is optically coupled with a GRIN lens. Typically, the mono-mode fiber and the second fiber have the same diameter and are mounted in a ferrule.

Abstract: A package for an optical device comprising two mating sections, each section including a rigid outer protective shell and a resilient inner body. The package is easily clamped together using snap clips, which are integral with the rigid outer protective shells. Preferably, strain relief is provided integrated on each end of the resilient bodies.

Abstract: The present invention relates to an in-line optical amplifier that can be coupled to optical fiber, wherein the amplifying medium has a substantially larger mode field than the optical fiber to which it is coupled. The present invention has realized a design to utilize a very high power pump launching a multimoded signal having approximately 1 W of pump power into a block of erbium doped glass having a mode field diameter orders of magnitude larger than the mode field diameter of erbium doped fiber. This invention provides a relatively inexpensive optical amplifier that is compatible for use in an optical fiber telecommunications system or for other uses. Advantageously, this invention provides a device that does not require unwieldy lengths of erbium doped fiber to form an amplifier. By using a block of glass having a rare earth therein, packaging, temperature stabilizing and temperature tuning of the amplifier also become practicable.

Abstract: The present invention relates to an in-line optical amplifier that can be coupled to optical fiber, wherein the amplifying medium has a substantially larger mode field than the optical fiber to which it is coupled. The present invention has realized a design to utilize a very high power pump launching a multimoded signal having approximately 1 W of pump power into a block of erbium doped glass having a mode field diameter orders of magnitude larger than the mode field diameter of erbium doped fiber. This invention provides a relatively inexpensive optical amplifier that is compatible for use in an optical fiber telecommunications system or for other uses. Advantageously, this invention provides a device that does not require unwieldy lengths of erbium doped fiber to form an amplifier. By using a block of glass having a rare earth therein, packaging, temperature stabilizing and temperature tuning of the amplifier also become practicable.

Abstract: An optical filter is disclosed having a pair of GRIN lenses disposed back to back, and having parallel end faces orthogonal to coaxial optical axes. Optical fiber tubes having optical fibers therein are disposed adjacent the GRIN lenses and have their inwardly facing end faces slant polished to lessen the effects of unwanted back reflections. This arrangement wherein optical axes of the optical fiber tubes are not parallel to the optical axes of the GRIN lenses is novel and inventive.

Abstract: To ensure the best optical coupling during the assembly of optical devices, such as WDM couplers, the elements making up the optical device are mounted with their longitudinal axes offset from each other, resulting in no two devices having identical structures. Moreover, it is also common for one of the elements to have a larger diameter than another. Therefore, it is very difficult to provide a package that will be satisfactory for every one of the optical devices. Furthermore, current manufacturing techniques require labor intensive steps that include one or more gluing or welding steps. Accordingly, the present invention provides an optical package that is suitable for optical devices with slightly varying structures, and that can be assembled relatively quickly and easily. The present invention relates to a package for an optical device, comprising two mating sections, each section including a rigid outer protective shell, and a resilient inner body.

Abstract: 1. A lensed sleeve has a holder having at least two substantially parallel rows of optical fibers which are offset from one another by about 2 &mgr;m or more. Generally these defective offset sleeves have to be discarded as their offset inhibits proper coupling of light, however in accordance with this invention a lens is disposed to receive light from at least optical fibers within one of the at least two rows of optical fibers. By using symmetry about the lens, light can be efficiently coupled between particular fibre ends on the offset rows. Advantageously, this invention provides a use for otherwise useless sleeves which did not meet intended tolerances.

Abstract: A useful device is provided for coupling or splitting optical signals from one port to another. The symmetry of a lens is utilized in a manner whereby two linear arrays of optical ports are disposed adjacent the optical axis of the lens equidistant from the optical axis of the lens. An at least partially reflecting optical element is disposed at a collimating end of the lens. Signals launched into one array of ports reflects back to the second array of ports at the same end. In another embodiment of the invention utilizing these two linear arrays of waveguides, two matched lenses having an element disposed between are used as a coupler/splitter. In this arrangement ports are positioned on opposite sides of the optical axis equidistant from it.

Abstract: A system and method are disclosed for demulitplexing closely spaced channels carrying optically encoded data. A composite optical signal having data channels corresponding to center wavelengths .lambda.1, .lambda.2, .lambda.3, .lambda.4, . . . .lambda.n are separated into two composite optical signals of first of which comprises data channels corresponding to center wavelengths .lambda.1, .lambda.3, . . . .lambda.n and a second which comprises data channels corresponding to center wavelengths .lambda.2, .lambda.4, . . . .lambda.n-1, wherein adjacent channels center wavelengths are separated from one another by a distance "d". A periodic multi-cavity Fabry-Perot etalon having a free spectral range of "2d" is coupled to a circulator for launching an input beam. The first of the two composite optical signals carrying channels 1, 3, . . . n is reflected from the input port of the etalon and the second of the of the two optical signals carrying channels 2, 4, . . . n-1 is transmitted through the etalon.

Abstract: A method and circuit is provided for more efficiently coupling light between two optical waveguides such as optical fibres. When the two waveguides are coupled to spaced apart collimating lenses such as GRIN lenses, the beam propagating between the spaced part lenses may be shifted. In this instance light can more efficiently be coupled out of the output optical fibre if it is angled with respect to the optical axis of the GRIN lens to which it is coupled. This invention provides an output fibre that is non-parallel with the optical axis of the lens it is coupled thereto.

Abstract: An optical multiplexing/demultiplexing device has a plurality of optical ports along a cascading optical path with wavelength-specific filters disposed at the ports. The filters are selected to form groups of at least two virtually identical filters. At least one "add" connection is provided for admitting a selected band into the optical path, the connection being disposed at a second or consecutive (third, fourth etc . . . ) filter of the same wavelength as the band being added. The device uses a single medium for processing optical signals, e.g. a single polygonal optical block or air.

Abstract: A method and apparatus of generating a test signal for broadcast to a plurality of locations for testing optical devices is disclosed. A tunable laser sweeps from a lower wavelength to a higher upper wavelength providing a test station with a variable input signal. A timing signal generated from the variable input signal is provided to the test station to determine the frequency of the variable input signal so that tests may be performed at several known wavelengths. Amplification is added to the system to provide sufficient power to the variable input signal and timing signal both split by a splitter to be provided to multiple test stations simultaneously.

Abstract: An optical device is provided having an input and an output terminal spaced equidistant from an optical axis of a graded index lens. An at least partially reflective surface is disposed spaced but adjacent from another end face of the graded index lens. The optical path length from the input or output terminal to a first end face of the lens is equal to the optical path length from the other end face of the lens to the at least partially reflective surface. The graded index lens has a length that collimates light launched from the input terminal to the at least partially reflective surface. Moving the input an output terminals toward or away from one another changes the angle at which light exits the other end face of the graded index lens, and thus changes the angle at which light is incident upon the at least partially reflecting surface.

Abstract: A connection assembly for two or more optical fibers, which is hermetically sealed by means of a thin-walled flexible metallic sleeve. The assembly comprises two fiber ends, each terminating in an optical component such as a lens, the lenses having distal end faces held together so that light can pass from one fiber to the other through the lenses, and a fiber tube is mounted on each fiber adjacent the proximal ends of the respective lens and is hermetically sealed to the fiber. Each fiber tube has a metallic coating, and the thin-walled metallic sleeve is connected by solder to the metallic coatings on the fiber tubes. Preferably, the metallic sleeve has a central portion with bellows-like convolutions.

Abstract: An optical device is disclosed wherein a first GRIN lens and a second GRIN lens having their optical axes offset. The first GRIN lens has one or more input ports at an input end. The second GRIN lens is disposed to receive light from the first GRIN lens. A reflecting surface is coated onto a second end face of the second GRIN lens or alternatively is disposed adjacent to the second end face and positioned to reflect an input beam of light launched into the input end face of the first GRIN lens. The reflective surface is at a location where light incident upon it to be returned to the first GRIN lens is collimated. By placing a filter and third GRIN lens between the first and second lenses double filtering may be achieved at the pass band or pass wavelength of the filter. Furthermore, the more simple arrangement including only first and second lenses provides a means of directing light into and out of the device at different angles or directions with respect to the optical axis of the first lens.

Abstract: This invention relates to a reflective optical isolating device having at least two stages. In one embodiment a polarization independent optical isolating device has an input/output end and a reflector at another end. An isolator is disposed between the reflector and the input/output end. The isolator includes a non-reciprocal rotator in the form of a Faraday rotator, and in one embodiment the isolator also includes two reciprocal rotators. A first end of the isolator includes a birefringent crystal for separating an input beam of light in an input direction and for combing two beams of light in an output direction. The isolator also includes a second birefringent crystal at the other end for combining a separated beam of light on route to the reflector and for separating a combined beam of light in the output direction. In one embodiment two separate single isolation stages are provided, and in another embodiment two stage isolation is provided without providing two single stages of isolation.

Abstract: A hybrid filter includes a dichroic interference WDM filter closely coupled with a Bragg grating. Preferably the Bragg grating is housed within a sleeve having an end face that is directly coupled with an end face lens of the WDM interference filter. The entire filter can be placed within a single housing and temperature controlled. Etalon effects are lessened by placing the Bragg grating as close as possible to the WDM filter. Multiple hybrid filters of this type optically coupled to an optical circulator provided multi-channel demultiplexing.

Abstract: A device for distributing an optical signal has an optical waveguide with a plurality of gratings disposed in series therein, the gratings having a predetermined reflectivity response within a specific wavelength range; an optical circulator having at least three ports, one of the ports serving as an input port for receiving the optical signal, and another port for removing at least a part of the optical signal reflected from one of the gratings; and control means for individually controlling at least some of the gratings to effect a change of the wavelength range of the reflectivity response of the gratings. The change may be a shift, an expansion or a compression of the range. The device can function as a signal distributor (router), an equalizer or a demultiplexer. The reflectivity response is preferably a sloped response.

Abstract: A system for automatically aligning optical components without active alignment techniques is provided. Optical components are placed into an alignment sleeve having an opening with a diameter sized to tightly receive optical components. Optical fibers having thermally expanded core ends are used to coupled light within the alignment sleeve. In instances where the optical fibers are offset from the longitudinal axis of the sleeve, means are provided to prevent rotation of an optical fiber tube holding the optical fibers.

Abstract: An attenuator capable of controllably attenuating at least two wavelengths of light is configured to have an optical waveguide section having at least two Bragg gratings disposed therein in series. The Bragg gratings have a sloped reflectivity response within a predetermined wavelength range. The sloped response is a function of refractive index variations within each of the grating elements. By compressing or expanding at least one of the gratings, the periodicity is modified so as to shift its central wavelength within a predetermined wavelength range.