Abstract: An optical interconnection apparatus including waveguide arrays such as waveguide lenses, waveguide gratings and star couplers, has improved efficiency realized by using a periodic array including in each period a combination of two radial waveguides. The array is formed with angular period ? between an input circle and an output circle and it includes an input section, connected to the input circle, and an output section connected to the output circle. The input section includes a single waveguide in each period and it is efficiently coupled with minimal loss to the output section, whose waveguides are approximately arranged with period ?/2 in the final region close to the output circle.

Abstract: An N×N crossconnect switch is implemented without the use of waveguide crossings. In one embodiment, the N×N crossconnect switch uses two non-parallel planar arrays of 1×2 and 2×1 switching elements combined with a cylindrical reflector. In another embodiment, the N×N crossconnect switch includes an input planar array and output planar array implemented on a single wafer both having a refractive index n>1 separated by a central region having a refractive index n0=1.

Abstract: A switching apparatus provides 1×2 and 2×2 switching functions having significantly reduced crosstalk levels using an imaging arrangement of three arms combined with two star couplers. In another 1×2 switching element embodiment, the input star coupler is replaced with an optical signal splitter. Application of the 1×2 and 2×2 switching elements include the realization of a variety of dilated N×N broadband switches with negligible crosstalk over very wide wavelength stopband characterized by two or more equally spaced zeros. The very wide crosstalk stopband enables the N×N broadband switch to switch a broadband wavelength division multiplexed input signal to the desired output port with very low crosstalk at the other output ports.

Abstract: A switching apparatus provides 1×2 and 2×2 switching functions having significantly reduced crosstalk levels using an imaging arrangement of three arms combined with two star couplers. In another 1×2 switching element embodiment, the input star coupler is replaced with an optical signal splitter. Application of the 1×2 and 2×2 switching elements include the realization of a variety of dilated N×N broadband switches with negligible crosstalk over very wide wavelength stopband characterized by two or more equally spaced zeros. The very wide crosstalk stopband enables the N×N broadband switch to switch a broadband wavelength division multiplexed input signal to the desired output port with very low crosstalk at the other output ports.

Abstract: An optical imaging arrangement includes a wavelength router having (1) N waveguides connected to different locations of the input curved boundary of the router, (2) a grating that forms multiple paths through the router and which transforms a particular wavelength applied to one of the N waveguides into N interleaved sets of equally spaced output images corresponding to the different orders of the grating (3) an output curve illuminated by the various images and (4) N interleaved sets of reflective elements placed along the output curve with properly chosen periodicity, such that all significant orders of each set of images are reflected back through the arrangement, so as to effectively produce a single input reflection in only one of the N waveguides of the arrangement, and the particular waveguide is determined by the phase shifts produced by the sets of reflective elements.

Abstract: An integrated 1×K wavelength-selective cross connect (WSC) comprises a demultiplexer arranged to couple each of the N individual wavelength in an input optical WDM signal to a different one of N demultiplexer outputs. Each of N planar beam steerers, arranged along the left edge of a free space region, receives and directs a different one of the N light beams from the demultiplexer to a location on the right edge of the free space region. Each of K gratings arranged along a different location on the right edge of the free space region multiplexes together any light beam received at that location. The 1×K WSC can be implemented with or without the use of crossovers.

Abstract: An optical interconnection apparatus including waveguide arrays such as waveguide lenses, waveguide gratings and star couplers, has improved efficiency realized by using a periodic array including in each period a combination of two radial waveguides. The array is formed with angular period &agr; between an input circle and an output circle and it includes an input section, connected to the input circle, and an output section connected to the output circle. The input section includes a single waveguide in each period and it is efficiently coupled with minimal loss to the output section, whose waveguides are approximately arranged with period &agr;/2 in the final region close to the output circle.

Abstract: An N×N crossconnect switch is implemented without the use of waveguide crossings. In one embodiment, the N×N crossconnect switch uses two non-parallel planar arrays of 1×2 and 2×1 switching elements combined with a cylindrical reflector. In another embodiment, the N×N crossconnect switch includes an input planar array and output planar array implemented on a single wafer both having a refractive index n>1 separated by a central region having a refractive index n0=1.

Abstract: An optical imaging arrangement includes a wavelength router having (1) N waveguides connected to different locations of the input curved boundary of the router, (2) a grating that forms multiple paths through the router and which transforms a particular wavelength applied to one of the N waveguides into N interleaved sets of equally spaced output images corresponding to the different orders of the grating (3) an output curve illuminated by the various images and (4) N interleaved sets of reflective elements placed along the output curve with properly chosen periodicity, such that all significant orders of each set of images are reflected back through the arrangement, so as to effectively produce a single input reflection in only one of the N waveguides of the arrangement, and the particular waveguide is determined by the phase shifts produced by the sets of reflective elements.

Abstract: A wavelength slicer uses a waveguide grating router having a periodic arrangement of reflectors in the output circular boundary of the router, which causes each input signal to pass twice through the router. The slicer includes two interleaved sets of equally spaced reflectors. Each set is slightly displaced from the output curve, and their displacements are properly chosen so as to effectively produce a phase shift of &pgr;/2 between the reflected signals. The reflected signals again pass through the router to produce two separate signals, containing respectively the even and odd channels of the input signal. A second slicer embodiment is realized using two gratings that are coupled to elliptical and circular reflectors. A wavelength filter is realized by forming on the output curve a set of equally spaced reflectors with spacing equal to an integer fraction of the spacing of the images.

Abstract: A 4×4 nonblocking switch arrangement includes eight 2×2 switches. The switch is nonblocking in that it is characterized by an algorithm that allows the destination of any two input signals to be interchanged by only changing the setting of one particular 2×2 switch. By removing one signal path a nonblocking 3×3 switch is obtained. Both switches have the minimum number of elements. These arrangements can be used as building blocks to construct larger switches and can be dilated to minimize crosstalk.

Abstract: An N×N crossconnect switch, for large N, is implemented using an arrangement of smaller wavelength routers combined with space switches. An N×N crossconnect switch is constructed in three stages, using a plurality of input space switches, a plurality of (N/m)×(N/m) router (whose reduced size N/m allows efficient realization in integrated form), and a plurality of output space switches. In the router, the number of wavelengths is reduced by a factor m. The input and output space switches can be implemented using crossbar or Clos type construction. In one arrangement each modulator is combined with a small space switch consisting of 2×2 elements. Each space switch can be realized with negligible crosstalk by using a dilated arrangement.

Abstract: An imaging arrangement technique is used to align a first waveguide on a first wafer to a second waveguide on a second wafer. The adaptive imaging arrangement is used on both the first and second waveguides when the first and second wafers are orthogonal to each other. In one embodiment, my imaging arrangement is used in an N×N optical cross-connect constructed using orthogonal abutting input and output planar arrays of N switches. If N is not too large, the optimum construction involves only two stages of trees, each incorporating an adaptive imaging arrangement allowing the input and output trees to be directly joined together without need for precise alignment.

Abstract: A dilated N×N optical cross-connect switch suitable for large N exhibits good efficiency (element count) without a significant increase in and reduced small depth (low loss) and crosstalk. The present arrangement consists of six levels of binary trees of 1×2 and 2×1 elements. The first two levels form the input stage, the third and fourth levels form the center stage, and the fifth and sixth levels form the output stage. In each of the input, center, and output stages, the odd number level is formed as a binary tree of 1×2 elements and the even numbered level is formed as a binary tree of 2×1 elements. Each stage is formed by directly joining together the 1×2 element binary tree with the 2×1 element binary tree. In one embodiment, depth is substantially reduced by using a symmetric arrangement of one or more 2×2 elements located in the vicinity of each junction between adjacent stages.

Abstract: A strict-sense nonblocking N×N spatial optical cross connect that employs planar lightwave beam steerers. The beam steerers allow for a modular design without requiring two-dimensional chip-to-chip waveguide interconnections. The modular design and the fact that the number of electrical control leads scales as NlogN in turn allows the possibility of constructing large, robust, solid-state cross connects. A cascaded beam-steerer design that substantially relaxes phase shifter strength requirements is also described.