Abstract: A system for determining a composite signal level at which a signal path begins to generate non-linear distortion. A reference test signal, which is preferably a short-duration burst of repeatable broadband energy, is passed through the signal path and received on a digital signal acquisition unit. An impaired received reference test signal is comprised of the transmitted reference test signal, linear distortion components, and non-linear distortion components. The impaired received reference test signal is digitally processed to reveal the non-linear distortion components. The impaired received reference test signal may be processed with a stored reference test signal to find a time-domain impulse response from which the uncorrelated distortion energy can be measured.

Abstract: A method of forming a grating in waveguide uses an ion exchange process to provide a waveguide region within and clad by a surrounding substrate and through an ion exchange process diffusing into the substrate an ion, such as such as Ag+, that is photosensitive and that provides a refractive index difference from adjacent non-diffused regions of the substrate. After the diffusion process, the step of exposing at least some of the waveguide region to light having a suitable intensity and duration to provide a permanent index change within regions of the waveguide region to form a grating is performed.

Abstract: The invention pertains to a thermo-optical switch comprising a cascade of 1×M optical switches, gates for selectively blocking and unblocking the output paths of the cascaded switch, and means for driving the 1×M switches and the gates, which means are arranged to switch a data signal from an input path of the cascaded switch to one of the output paths, wherein the said means are also arranged to switch an unwanted signal, by means of a number of the remaining 1×M switches, to at least one of the remaining output paths. In the cascaded switch according to the invention, the generated heat is distributed evenly over the area of the switch and the overall amount of heat generated is reduced.

Abstract: The invention pertains to a cross-linkable fluorinated polymer comprising the carbonate moiety having formula (I) wherein n=1-10 and m=0-9. Preferably, the polymer further comprises a cross-linkable moiety derived from a diol selected from (II) and (III) wherein A, A1, and A2 are independently a bond or C1-12 alkylene, or together with the carbon atoms to which they are bonded form a 5- or 6-membered ring; B is independently O or C1-4 alkyl; Q is —CO—C(=E)D, wherein D is H or C1-4 alkyl, and E is C1-6 alkylidene; and each of the alkyl, alkylene, and alkylidene groups may be halogenated. The polymers of the invention can be used in cladding layers or waveguides, in particular for thermo-optical devices.

Abstract: An optical intensity modulator is disclosed which comprises a waveguide containing a core adjacent to at least one cladding layer and exhibits a refractive index n(core) different from the refractive index n(cl) or the cladding layer, where the waveguide is a bent channel waveguide and the intensity modulator contains a heater or cooler for altering the temperature at or near the bend. The core and the cladding layer exhibit different thermo-optic coefficients at the bend such that the contrast between n(core) and n(cl) can be changed by altering the temperature. The optical intensity modulator is more compact in size and more efficient with regard to energy consumption. The invention also pertains to thermo-optic switches and thermo-optic cascaded switches comprising the optical intensity modulator and to the use of the optical intensity modulator as a tunable attenuator.

Abstract: The invention pertains to a polymeric phased array comprising an MMI input coupler with N inputs and an MMI output coupler with M outputs, N and M being natural numbers greater than or equal to 1, wherein the couplers are optically connected by means of an optical array comprising a series of optical waveguides, each of which differs from its nearest neighbour, in optical path length by a predetermined fixed amount, wherein the physical length of all the waveguides is substantially equal. The said phased arrays are less sensitive to changes in temperature and physical aging.

Abstract: An optical switch having a TEMC fiber and a displacement plate. The TEMC fiber having an input core and a plurality of output cores. The displacement plate coupled to the TEMC fiber to receive a light beam from the input core. The displacement plate to direct the light beam to one of the plurality of output cores by rotating the displacement plate a predetermined angle.

Abstract: A laser system is disclosed wherein a tunable laser signal has encoded within it information related to its wavelength at any instant in time. This encoding in one example is performed by modulating the signal to contain its wavelength information. This is particularly useful in a distributed system for testing optical components, wherein at a test site, the test station must determine the wavelength of light at which a component was tested.

Abstract: Multiple N×M and M×N optical switchers that may be combined within a single package to produce an N×N optical switch, where M is greater than N. The use of multiple optical switchers within an optical switch package allows for a higher degree of isolation than may be achieved than with a single stage optical switch. The optical switchers may be reflection type devices having no moving parts. The optical switchers may include a magneto-optic Faraday rotator having a thin crystal that is easy to grow and consumes less space, thereby enabling a smaller, less expensive, and less complex optical switch.

Abstract: An optical device is described. In one embodiment, the optical device includes first and second concave diffraction gratings, first and second concentrators, first and second sets of fibers, and an array of optical elements. The first concave diffraction grating reflects light from an input beam into multiple light waves of different wavelengths focused at spatially separate locations. The first concentrator has a first set of light guiding channels to transfer the light waves. The first set of fibers is optically coupled to the first set of light guiding channels. The array of optical elements includes optical elements that have at least one input and at least one output. Such inputs of each optical element in the array is coupled to one of the first set of light guiding channels. The second set of fibers is optically coupled to outputs of optical elements in the array. The second concentrator has a second set of light guiding channels.

Abstract: Methods and apparatuses for tuning optical devices are described. Optical devices can be tuned by inserting tuning plates into the optical path(s) of the devices. Tuning plates can be, for example, quartz plates. By selecting the appropriate thickness and optical axis orientation, the tuning plate can be used to tune the optical devices to a precision that is unavailable through manufacturing specifications and tolerances of the components of the optical device alone. Because quartz has a relatively small birefringence, tuning plates made with quartz can be thicker, and therefore manufactured more precisely than the components of the optical devices.

Abstract: Methods and apparatuses for filtering optical channels to provide, for example, an interleaver, or a deinterleaver. A multi-plate comb filter is used to separate subsets of channels and for mixing subsets of channels. Interleavers and deinterleavers having one or more multi-plate comb filters can be used to increase the bandwidth of an optical network. The interleavers and deinterleavers can be used to interface components designed for a first channel spacing to components designed for a second channel spacing.

Abstract: Interleaver/deinterleaver apparatuses for combining/separating optical channels are described. An interleaver/deinterleaver apparatus is described as folded when an optical signal is directed through a single crystal multiple times. Single-pass refers to the optical signal following a (folded) path through the apparatus a single time. When operating as an deinterleaver, the interleaver/deinterleaver separates an optical signal (e.g., WDM signal) into subsets of optical signals (e.g., channels). When operating as an interleaver, the interleaver/deinterleaver mixes subsets of optical signals (e.g., channels) into a multiplexed (e.g., WDM) optical signal. The interleaver/deinterleaver apparatus can be used to increase the bandwidth of an optical network. For example, the interleaver/deinterleaver can be used to interface components designed for a first channel spacing (e.g., 100 GHz) to components designed for a second channel spacing (e.g., 200 GHz).

Abstract: The traditional solution to monitoring the pump laser power uses the back facet of the pump laser to monitor its power. However, stability and aging issues of the back facet may make it difficult or even impossible to measure the pump power to a high degree of accuracy using this method. Pump lasers often use fiber Bragg gratings to stabilize their wavelength. However, if an in-line optical fiber blazed Bragg grating is used, then the pump power is coupled out of the grating to a detector and monitored. The method of the present invention minimizes components and provides a direct monitoring of fiber coupled power. Alternatively, light coupled out of a WDM is used in a similar manner to monitor the pump power.

Abstract: Interleaver/deinterleaver apparatuses for combining/separating optical channels are described. An interleaver/deinterleaver apparatus is described as folded when an optical signal is directed through a single crystal multiple times. Double-pass refers to the optical signal following a (folded) path through the apparatus twice. When operating as an deinterleaver, the interleaver/deinterleaver separates an optical signal (e.g., WDM signal) into subsets of optical signals (e.g., channels). In one embodiment, deinterleaving optical signals separates an optical signal into even and odd International Telecommunications Union (ITU) channels. When operating as an interleaver, the interleaver/deinterleaver mixes subsets of optical signals (e.g., channels) into a multiplexed (e.g., WDM) optical signal. The interleaver/deinterleaver apparatus can be used to increase the bandwidth of an optical network. For example, the interleaver/deinterleaver can be used to interface components designed for a first channel spacing (e.

Abstract: An apparatus capable of operating as an interleaver, a deinterleaver, a filter, or some combination thereof is described. An optical device that can be configured to multiple different optical components. In one embodiment, the optical device can be configured to operate as a single double-pass interlayer/deinterleaver, as two single-pass interleaver/deinterleavers, or as one or more filters. In one embodiment, the optical device has ports on two or more planes and a birefringent element that occupies the two or more planes. Connections between the two or more planes can be made by walk-off crystals internal to the optical device or between ports by connections that are external to the optical device to configure the optical device.

Abstract: The invention pertains to a (cascaded) optical switch at least comprising one input path, a number of output paths, one or more switch or splitter stages each comprising one or more optical switches or splitters, and at least one gate for optically disconnecting the output paths from the input path, wherein that gate is located at or near the input path. The cascaded switches according to the present invention are compact exhibit a reduced complexity and an improved insertion loss.

Abstract: The invention pertains to a thermo-optical device comprising a waveguiding structure (1) which comprises at least one input light path (2) and at least two output light paths (3,3′) forming a first y-splitter (4), at least one output light path (3,3′) being provided with primary heating elements (5,5′), characterised in that the output light paths (3,3′) are provided with an additional branch (6) forming a second y-splitter (7), wherein at least one of the branches (6,6′) is provided with a secondary heating element (8,8′). The additional branches (6) may be positioned in the opposite direction, such that in each of the second y-splitters (7) one branch (6′) coincides with one of the output light paths (3,3′) of the first y-splitter (4).

Abstract: The present invention provides for an optical waveguide device comprising a gratings, primarily in the form of fiber Bragg gratings, which are sampled, interleaved and chirped to achieve different functions. By interleaving sampled fiber Bragg gratings, each with a grating period which differs from the others by an amount corresponding to a multiple of a channel spacing, a predetermined and useful optical spectrum can be produced for the optical waveguide device. By making the sample periods for the fiber Bragg gratings different from each other, the resulting reflection spectrum has missing reflection peaks. A bandpass filter can be effectively created. Furthermore, by discretely varying the grating periods of sampled fiber Bragg gratings at intervals along the optical fiber containing the gratings, a more uniform optical spectrum is produced for the optical waveguide device.

Abstract: A method and apparatus for optically isolating multiple core optical fibers while at the same time substantially reducing polarization mode dispersion, is disclosed. A multiple core fiber is optically coupled to optical birefringent elements, reciprocal and non-reciprocal rotators, and through a lens assembly to a multiple core optical fiber output.