Abstract: A method and device is disclosed for dispersion compensation of an optical signal having periodic dispersion within a multi-channels system. For example interleaved optical channels often exhibit dispersion having a characteristic that is repeated in adjacent channels. By providing a periodic device in the form of a multi-cavity GT etalon having a free-spectral range that corresponds to the channel spacing the dispersion in the interleaved signal can be lessened and practically obviated or balanced to a desired level. Advantageously, the input and output angle of the signal can be varied to provide fine tuning. This invention provides a device and method to achieve that end.

Abstract: A micro-optical delay element for a polarization time-division multiplexing scheme is disclosed wherein two light beams are provided to a polarization beam splitter/combiner (PBS/C) in the absence of optical fiber. At least one beam exiting a modulator is collimated and reaches the (PBS/C) unguided as a substantially collimated beam. In this manner the polarization state of the beam is substantially unchanged. This obviates a requirement for polarization controllers.

Abstract: The invention disclosed relates to a device for multiplexing/demultiplexing a multi-band DWDM system, providing reduced insertion losses. The device comprises first and second planar waveguides, a light dispersive element having a periodic frequency spectrum, interconnecting the first and second planar waveguides, a plurality of N input waveguides, connected to the first planar waveguide, and a plurality of M output waveguides, connected to the second planar waveguide, wherein the M outputs are each separated by a frequency interval &Dgr;f, the N inputs are each separated by substantially M*&Dgr;f, the free spectral range (FSR) equals substantially N*M*&Dgr;f, where N is an integer greater than 1, and M is an integer equal to or greater than N. In one embodiment of the invention, wherein the telecommunications window is divided into a plurality of sub-bands of M channels, a temperature controller is included to provide individual temperature set points for each sub-band, to reduce wavelength centering errors.

Abstract: A wavelength demultiplexer having a substantially flat output response within its passband is disclosed. The demultiplexer comprises a first wavelength demultiplexer optically coupled to a second wavelength demultiplexer. The first wavelength demultiplexer has a free spectral range approximately equal to channel spacing of the second wavelength demultiplexer thereby providing the substantially flat output response within the passband. The first wavelength demultiplexer is a resonant optical cavity, absent distinct output ports, and light propagating between the first wavelength demultiplexer and the second wavelength deimultiplexer is unguided. The absence of distinct output ports in the first wavelength demultiplexer reduces ripples in the substantially flat output response within the passband. Alternatively, the first wavelength demultiplexer is replaced by an MMI-phasar.

Abstract: A 1½×2 optical switch has two GRIN lenses, each lens having two ports on its respective outward end face. The switch has a transmissive wedge-shaped switching element disposed between the GRIN lenses. When the switching element is disposed in the path between the GRIN lenses, a single connection is established between a port of the first GRIN lens and a port of the second GRIN lens, while light is prevented from coupling between the remaining ports.

Abstract: This invention relates to invention relates to a variable slope optical filter in the form of a Fabry-Perôt etalon having an end face with a variable finesse. A method for filtering and a variable slope optical filter for in-line use with an optical amplifier signal is also disclosed. 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 a 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. Relative movement between the filter and the optical amplifier signal is provided to vary the slope of the filter by means of varying the amplitude wavelength response of the filter.

Abstract: A method and device is disclosed for dispersion compensation of an optical signal having periodic dispersion within a multi-channels system. For example interleaved optical channels often exhibit dispersion having a characteristic that is repeated in adjacent channels. By providing a periodic device in the form of a multi-cavity GT etalon having a free-spectral range that corresponds to the channel spacing the dispersion in the interleaved signal can be lessened and practically obviated or balanced to a desired level. This invention provides a device and method to achieve that end.

Abstract: This invention relates to invention relates to a method for filtering and 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 a 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. Relative movement between the filter and the optical amplifier signal is provided to vary the slope of the filter by means of varying the amplitude wavelength response of the filter.

Abstract: Tuning to maximize the isolation provided by an optical isolator to one of a predetermined plurality of wavelengths is achieved by tilting the isolator with respect to an input beam of light. Further tuning to a peak response for a given wavelength is achieved by rotation of the isolator about its longitudinal axis while or after tilting. In the manufacture of the isolator a test beam is launched into an output port end directed toward the input end. Tilting, or tiling and rotating is initiated and light at the input end is measured while tilting/rotating. When the position is determined where the minimal amount of light is measured, the optical elements are glued or secured in place, thereby providing a way to alter the response of an isolator for a given wavelength of input light.

Abstract: An optical system for coupling light from a monolithic waveguide chip from one optical path to another on different layers of the chip or into or out of the chip along an edge thereof by coupling a GRIN lens to the edge. Coupling a GRIN lens having a reflective end allows light to be launched out of and back into the waveguide chip. Alternatively a GRIN lens having a plurality of fibers coupled thereto can be used to couple signals carried by the fibers into the waveguide chip.

Abstract: A wavelength demultiplexer having a substantially flat output response within its passband is disclosed. The demultiplexer comprises a first wavelength demultiplexer optically coupled to a second wavelength demultiplexer. The first wavelength demultiplexer has a free spectral range approximately equal to channel spacing of the second wavelength demultiplexer thereby providing the substantially flat output response within the passband. The first wavelength demultiplexer is an MMI-phasar having a tapered MMI coupler.

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: 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: A multiplexing/demultiplexing optical circuit provides a demultiplexed output spectrum of channels having a flat amplitude response without sacrificing optical power. A phased array implementation and a diffraction grating implementation both rely on a first dispersion of the beam to be demultiplexed and subsequent division of the wavelengths into channels. Local inversion is induced within each channel of the dispersed wavelengths about a channel central wavelength. After the wavelengths are spatially inverted, they are once again provided to a dispersion element or array effectively nullifying the dispersion effects across the channel band to provide output channels having a substantially “flat-tops”, while providing good channel separation through global dispersion of all the wavelengths.

Abstract: A tuned multiple fiber optical connector and a method for tuning same is disclosed. A first connector housing retains each of a first plurality of optical fiber ends in a predetermined location. The first connector housing has a first key element. A core of each of the first plurality of optical fiber ends is oriented in a predetermined fashion with respect to the first key element. A second connector housing retains each of a second plurality of optical fiber ends in a predetermined location. The second connector housing comprises a second key element. A core of each of the second plurality of optical fiber ends is oriented in a predetermined fashion with respect to the second key element. The first and the second connector housings are coupled such that the key elements are disposed in a predetermined relation one to the other.

Abstract: This invention relates generally to custom optical filters such as filters relating to, flat-top WDM multiplexer/demultiplexers, flat-top and peaky comb filters or reconfigurable add & drop filters. The embodiment disclosed below is based on mid-dispersion wavelength bands processing, wherein the optical spectrum is dispersed in two steps; in-between these two steps, the wavelength bands are manipulated in the focal plane, for example by being moved, reflected, absorbed, inverted, magnified or reduced to achieve a particular result. A masked mirror or masked transmissive element selects wavelength by position. The mask shape for relatively complex filtering functions is much simpler than currently used for collimated beams because of the correlation between position and wavelength. Inversion of channel bands or movement of channel bands in two dimensions in the focal plane, in particular, enables the construction of numerous useful devices.

Abstract: A method and system is provided wherein an n channel system is equipped with n uncooled inexpensive lasers not requiring optical isolators provide optical signals to the n broad channels. Advantageously, the system can be installed at a reasonable cost to the first n users and be upgraded in number of channels and cost as the need for the system to evolve and grow arises. Each of the n uncooled lasers are tuned such that at ambient temperature, their central wavelength is below their respective channel mid wavelength.

Abstract: An optical coupling arrangement for use in an optical filter is disclosed wherein optical fibre are disposed only along one line in one orientation across an end face of an optical fibre tube having a slanted end face. By disposing slanted/polished optical fibre end faces along a line that is orthogonal to a longitudinal axis of the optical fibre tube, optimum coupling of light is achieved.

Abstract: Combinations of optically coupled Generalized Mach-Zehnder Interferometers (GMZIs) result in switches of greater switching capacity than an isolated GMZI. In a preferred form, the present invention provides a balanced non-blocking switch by using symmetrical configurations of optically coupled GMZIs, and also provides a cascaded non-blocking switch by cascading an N×N GMZI with a (N−1)×(N−1) non-blocking switch.

Abstract: A method and circuit is disclosed wherein two waveguides coupled to an optical resonant ring resonator are further coupled such that beams propagating therein interfere with one another to provide a desired output response. In one embodiment, multiplexed channels of light can be demultiplexed by the device described heretofore, or alternatively, the phase relationship between these two beams can be altered prior to their being combined to provide, for example, a linearized output response useful in applications such as wavelength locking. By varying the reflectivity of the FSR and the coupling ratios and/or by varying the phase relationship between the two beams, a variety of desired output responses can be realized.