Abstract: This invention relates to a method for filtering and to a variable slope optical filter for in-line use with an optical amplifier signal. The filter has a wavelength response that is substantially linear in slope within a band of operation wavelengths of the amplifier; the slope of the filter in an operating band of wavelengths is between zero and only one of a positive or negative number; furthermore the filter has an amplitude response that has an opposite and counter slope as a function of wavelength to that of a gain tilt of the amplifier within the operation band of wavelengths. The filter having means of operating on polarized light such that different wavelengths within a band of wavelengths within the operation band are subject to different levels of attenuation according to their polarization state. A wave plate having a predetermined thickness provides a relative polarization difference between two wavelengths of an incoming beam in a controlled manner.

Abstract: The present invention relates to a circuit for monitoring optical signals in a multiple channel system. A tunable band pass filter receives and input signal comprising multiple channels each having a different wavelength and predetermined channel spacing. Output from the tunable filter is directed to a second filter having a periodic response with wavelength, such as an etalon. The response is designed to block wavelengths of light corresponding to the channels, permitting noise in the inter-channel space to be measured by a detector. A reference circuit launches light from a broad band source through a Bragg grating into the tunable filter. The Bragg grating reflects a known reference wavelength. Light which passes from the reference source through the tunable filter is also passed through the second filter to a detector. When a notch is detected by the reference detector, the tunable filter is known to be tuned to the reference wavelength.

Abstract: An apparatus for simultaneously or selectively grinding ends of a plurality of optical fibers held by optical fiber end devices such as connectors including ferrules. The apparatus has a holder plate having a plurality of types of supporting structures for fixing and supporting a plurality of types of optical fiber end devices with optical fibers connected thereto. Spring or weights are used for urging ends of the optical fibers on the optical fiber end devices supported by the supporting structures. A circular-path-based relative motion is caused to occur between the holder plate and the grinding plate. Each of the optical fiber end devices is a connector including a ferrule. In such a case, the plurality of types of optical fiber end devices may be connectors whose end surfaces are to be ground at different angles or may be the connectors of different connection types.

Abstract: An optical apparatus is disclosed that includes a first Z×T optical switch having Z input ports and T output ports, where T is at least 2, optically coupled to an integrated optical generalized Mach-Zehnder interferometer. The result is an optical switch, which is operated using a smaller number of control elements and control levels than the generalized Mach-Zehnder interferometer alone.

Abstract: An interleaver/de-interleaver circuit comprising: a first coupler having an input port and at least two output ports; a second coupler having two input ports and two output ports, the at least two output ports of the first coupler being optically coupled with the two output ports of the second coupler; an optical cavity having a partially reflective surface having a reflectivity E at one end and a reflective surface at another end with a higher reflectivity E′, the optical cavity being optically coupled to one of the at least two output ports of the first coupler and at one of the two output ports of the second coupler.

Abstract: This invention discloses and optical filtering arrangement wherein a filter element having a coated substrate is disposed such that its ports on one side face the substrate instead of facing the coating upon the substrate. Hence, when the filter is positioned a distance from the ports, its coating side faces away from the ports while its substrate faces the ports. In this arrangement stress applied by adhesives or solder upon the coating can be eliminated.

Abstract: The present invention relates to multi-wavelength filtering devices and more particularly to a multi-channel multiplexer/demultiplexor using at least one multi-port optical circulator and a plurality of Bragg optical fiber gratings or other wavelength selective means. Advantageously a drop or add/drop optical circuit including the combination of a Bragg grating providing a strong reflective response for substantially completely separating a single channel of a band of wavelengths from a plurality of other channels in a multi-channel signal, with a Bragg grating of lower reflective response which is capable of providing group delay compensation to lessen the effects of group delay introduced by the strong Bragg grating with isolation between the Bragg gratings provides a device for accurately and efficiently separating channels from a multiple channel signal with low loss.

Abstract: Broad wavelength tuning range are achieved in an effectively reset-free, optical, automatic polarization controller by providing a device and method for varying the polarization of an input beam of light. A block of electro-optic material has two pairs of electrodes for applying a voltage across the block. Light is launched into an input end of the block for receiving the input beam of light. A controller controls a quadrature voltage applied to the first and a second pair of electrodes; the quadrature voltage has the form of a magnitude and an angle. The quadrature voltage can be varied in such a manner as to orient a given electric field within the electro-optic material through a plurality of angles, for example between 0 and 2&pgr; radians; the magnitude of the quadrature voltage can be set to create an arbitrary retardance from 0 to 2&pgr;. Any output polarization state can be realized by appropriately varying the magnitude and angle of the voltage applied to the Vx and Vy electrodes.

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: An optical attenuator for attenuating a collimated beam of light propagating along an optical path while preserving the composition of polarization of the collimated beam of light is disclosed. The optical attenuator comprises a beam attenuator for attenuating a portion of the collimated beam of light when a portion of the beam attenuator is disposed within the optical path. The beam attenuator has a cross section along a plane perpendicular to the direction of propagation of the collimated beam of light of the portion of the attenuator in the shape of a wedge. The attenuation is varied using a controller for moving the beam attenuator in order to vary a size of the portion of the wedge within the optical path.

Abstract: An add-drop optical circuit is provided comprising: a first multiplex/demultiplexer for demultiplexing a composite optical signal having a plurality of channels, a second multiplex/demultiplexer for multiplexing a plurality of signals into a composite optical signal; waveguides disposed between the first demultiplexer and the second multiplexer/demultiplexer; and a plurality of 11/2.times.2 optical switches coupled to at least some of the waveguides for adding and dropping optical signals, the optical switches substantially preventing optical signals from propagating from an add port to drop port.

Abstract: An optical switch mechanism for reflecting an input light beam from an input port to a reflection output port in a first state and for transmitting an input light beam to a transmission output port in a second state is disclosed. The switch mechanism comprises a block made of a light transmissive substrate. The block contains a cavity, which is divided by a light transmissive diaphragm into a reflective portion and a transmissive portion. At the input port a light beam is coupled into the block such that the light beam encounters a reflective surface at an angle greater than a critical angle determined by the refractive indices of the substrate and a reflective fluid retained in the reflective portion of the cavity. When the reflective fluid is in contact with the reflective surface the light beam is totally reflected to a reflection output port.

Abstract: An optical element having a periodically varying spectral response is used to flatten the spectral amplitudes within each of a group of multiplexed channels having different predetermined central wavelengths with uneven spectral amplitudes peaked around the central wavelengths. Spectral equalization is achieved by having the amplitude valleys of the spectral response aligned individually with the different central wavelengths. The optical element comprises an optical cavity, which forms part of a low-finesse Fabry-Perot etalon.

Abstract: An optical switching system particularly useful in optical networks where waveguides are required from one node to several others, to provide multiple paths in the event of an outage on a particular waveguide is provided. The switching system is a one sided switch having p ports and allows any of the p ports to be connected with any other of the p-1 ports.

Abstract: A design for producing bandpass filters with passbands that are centered at the same wavelength for each mode of polarization. Filters are of the all-dielectric type that consist of single and multiple cavities of bandpasses. All of the layers are of the Quarter Wave type for ease of manufacture with the possible exception of the last few layers being modified to reduce reflection into a new media. The basic structure of the multi-layer bandpass filter is as follows: (XY).sup.n (YY)(XX).sup.m (YY)(YX).sup.n where n and m are integers and wherein X is one of a high refractive index layer and a low refractive index layer; and, wherein Y is the other of the high and low refractive index layer, X and Y being opposite indexes of refraction.

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: A device for releasably mounting an adapter designed for coupling two fiberoptic connectors, e.g. SC connectors, has a body with a cavity sized to match the outside profile of the adapter when inserted in said cavity for a securely captive position. The adapter has two outside spring clips. The cavity has a bottom wall, two side walls, an upper wall and two detentes disposed to engage the spring clips when the adapter is fully inserted into the cavity. A leaf spring is disposed at the bottom of the cavity and is adapted to bias the adapter towards the upper wall of the cavity whereby the spring clips engage the detentes. The bottom wall and the spring are designed to form an enlargement of the cavity in the front part thereof when the spring is depressed, the enlargement enabling a manual tilting of the adapter causing a disengagement of the clips with the detentes whereby the adapter can be removed.

Abstract: A system for modifying an input optical signal by reducing its bandwidth and modifying its central wavelength has an optical circulator with at least three ports and at least two optical filters coupled to consecutive ports of the circulator. The first filter produces a predetermined reflected band off the input optical signal. The second filter produces a predetermined transmission band as a part of the reflected band. Either or both of the optical filters are tunable to shape and trim the input signal in a predetermined manner. A multi-channel and cascade configurations may be formed. The system may serve e.g. as a tunable filter or as an add/drop module in WDM communication networks.

Abstract: An optical isolator for passing light in a forward direction with greater intensity than reverse directed light, is provided. The device includes a conventional isolating means having at least two birefringent crystals, and a non-reciprocal rotating element disposed between the two crystals. The isolating means is disposed between two substantially collimating GRIN lenses, and a thermally expanded core (TEC) output optical fiber is coupled to one of the two lenses and an optical fiber having a thermally expanded core optically coupled to the other of the two collimating lenses. Unwanted reflected incident light is poorly coupled into the input TEC optical fiber due the angle of incidence at the fiber end.

Abstract: An optical demultiplexor utilizes a single optical interference filter disposed between an input end and an output end of the device. The filter is preferably housed within a cavity in a glass block having an upstanding input end, endwall. The optical filter is a wavelength selective means having a wavelength characteristic dependent upon an angle of incidence. The device has a plurality of reflective surfaces disposed at the input end for reflecting light reflected from the filter, back to the filter at different predetermined angles. Each different predetermined incident angle allows a different predetermined wavelength of light to pass through the filter to an output end being spatially separated from other predetermined wavelengths that pass through the filter. The reflective surfaces are preferably formed in the upstanding endwall of the glass block. Sixteen channels can be separated by this demultiplexor.