Abstract: In one method, two light signals, of the same optical frequency, but having orthogonal states of polarization, are transmitted through an optical device and the mean signal delay of each of the light signals is measured. Calculations, based upon disclosed relationships, provide the polarization-independent delay (&tgr;0) through the optical device based upon the mean signal delays (&tgr;g1 and &tgr;g(−1)) of each of the light signals. By comparing &tgr;0 at adjacent wavelengths, the chromatic dispersion of the optical device can be accurately measured even in the presence of PMD. In a second, similar method, four light signals of non-degenerate polarizations states that span Stokes space are utilized. In a modification of the above-described methods based on the measurement of pulse delays, the methods are adapted to the measurement of phase delays of sinusoidally modulated signals.

Abstract: In one method, two light signals, of the same optical frequency, but having orthogonal states of polarization, are transmitted through an optical device and the mean signal delay of each of the light signals is measured. Calculations, based upon disclosed relationships, provide the polarization-independent delay (&tgr;0) through the optical device based upon the mean signal delays (&tgr;g1 and &tgr;g(−1)) of each of the light signals. By comparing &tgr;0 at adjacent wavelengths, the chromatic dispersion of the optical device can be accurately measured even in the presence of PMD. In a second, similar method, four light signals of non-degenerate polarizations states that span Stokes space are utilized. In a modification of the above-described methods based on the measurement of pulse delays, the methods are adapted to the measurement of phase delays of sinusoidally modulated signals.

Abstract: Four different light signals, all of the same optical frequency, but, having different states of polarization, are transmitted through an optical device and the mean signal delay of each of the light signals is measured. Calculations, based upon the relationship, &tgr;g=&tgr;0−½ {right arrow over (&OHgr;)}·{overscore (s)}, describing the polarization dependence of &tgr;g (a measured mean signal delay) through the device as a function of &tgr;0 (a polarization independent delay component of the device), {right arrow over (&OHgr;)} (the PMD vector at the device input) and {overscore (s)} (the input Stokes vector of the light signal), yield the PMD of the device. Also, by comparing data taken at adjacent wavelengths, the chromatic dispersion of the optical device can be accurately measured even in the presence of PMD.

Abstract: The present invention consists of a method and apparatus for measuring first and higher order PMD vectors in optical fibers. For each first-order PMD vector determination, two distinct polarization states are sequentially injected into an optical device under test for each of a pair of frequencies &ohgr; and &ohgr;+&Dgr;&ohgr;f. A Stokes vector s1 representing the first polarization state must not be parallel or anti-parallel to a Stokes vector sa representing the second polarization state, but the relative angle between s1 and sa need not be known. The frequency interval &Dgr;&ohgr;f is large to obtain a high signal-to-noise ratio. Thus, four light beams are injected, the first at frequency &ohgr; and polarization s1, the second at frequency &ohgr; and polarization sa, the third at frequency &ohgr;+&Dgr;&ohgr;f and polarization s1, and the fourth light at frequency &ohgr;+&Dgr;&ohgr;f and polarization sa.

Abstract: An apparatus and method for simultaneously taking measurements that are used for determining PMD vectors. This reduces the time interval over which all measurements are taken and reduces inaccuracy caused by PMD variation during the time measurement interval. The apparatus and method may be used in conjunction with any technique for calculating PMD, such as the Poincare Sphere Technique or Jones Matrix Eigenanalysis. The apparatus simultaneously produces multiple light beams. To distinguish each light beam from the others, each beam is given a distinct modulation. All the beams are then combined and passed through the optical device under test. A polarization measuring device then measures the output polarization of the combined beam and outputs one or more composite electrical signals that describe the Stokes components of the output polarization of the combined beam and that have the same modulations present in the original combined beam.

Abstract: It is known to form an optical waveguiding thin film on a substrate. For various practical reasons, it is often desired that an optical beam coupled to the film be laterally confined so as to propagate only in a longitudinal stripe portion of the film. As disclosed herein, this is accomplished by depositing spaced-apart elements in contact with one surface of the film to establish in a narrow longitudinal region of the film between the elements an effective index of refraction that is higher than the index of the remainder of the film. In this way a longitudinal waveguiding stripe is formed on the film without the necessity of irradiating, etching or otherwise directly treating the film itself.

Abstract: A tunable permanently fixed diffraction grating is interposed in the path of an optical beam propagated in an integrated-optics device. Tuning is accomplished, for example, by establishing a variable electric field in the propagating medium to control its refractive index. In that way the effective grating spacing is changed. As a result tunable optical filters and intensity modulators are thereby realized.

Abstract: An optical switching network employing a plurality of optical switching crosspoints is implemented by providing the first and second pluralities of strip waveguide channels passing one over the other in parallel planes separated by an intervening medium. The implementation is further characterized by including at each of the proposed switching crosspoints, that is, at the regions of closest approach of the different strip guides, beam-guide couplers such as grating-type couplers to couple the modulated optical energy from one of the first plurality of channels to one of the second plurality of channels through an intervening, supporting medium. There are provided two couplers at each optical crosspoint; and they are controllable between coupling and noncoupling conditions with respect to their respective waveguide channels.

Abstract: An optical switch of the switched directional coupler type is provided with an adjustable cross-over state as well as an adjustable straight-through state, in order to provide reduced crosstalk in the cross-over state, for example, when the switches are used in an optical switching system. The improved switch is based on asynchronous or phase-mismatched coupling between two parallel optical strip guides driven by electrodes to which the voltage is applied. In order to use phase-mismatched coupling instead of phase-matched coupling for the cross-over state, in order thereby to obtain electrical adjustability of that state, the driving electrodes are split into two or more sequential sections, thereby defining two sequential coupling sections of the parallel optical strip guides. The cross-over coupling is then achieved by switching the mismatch conditions so that at the point of partial coupling the "nonoriginating" guide appears to the coupled optical waves to be the "originating" guide.

Abstract: It is known to form an optical waveguiding thin film on a substrate. For various practical reasons, it is often desired that an optical beam coupled to the film be laterally confined so as to propagate only in a longitudinal stripe portion of the film. As disclosed herein, this is accomplished by depositing a material on a selected portion of the film surface to establish in a narrow longitudinal region of the film an effective index of refraction that is higher than the index of the remainder of the film. In this way a longitudinal waveguiding stripe is formed in the film without the necessity of irradiating, etching or otherwise directly treating the film itself.

Abstract: In the disclosed common medium multichannel exchange and switching system, optical carrier frequencies and bandwidths are employed and provide switched channels of unprecedentedly large bandwidth. At the same time, the switching network at optical frequencies is of such unprecedentedly small size that it promises to be implementable via integrated optics on only one integrated circuit chip, or, at most, a few chips of suitable material. The system is adapted to optical frequencies in that the common medium is an optical strip guide and optical directional channel-separation filters are employed to couple a plurality of switched customers or switched facilities on to or off of the common medium. At the same time, the system is compatible with the central processing control of the general type employed in current electronic switching systems.