Abstract: A filtering device such as an optical interleaver/deinterleaver includes first and second optical couplers each having two inputs and two outputs. The inputs of the first coupler are adapted to receive input optical signals to be filtered and the outputs of the second coupler are adapted to provide filtered output optical signals. A first optical waveguide optically couples a first output of the first coupler to a first input of the second coupler. A second optical waveguide optically couples a second output of the first coupler to a second input of the second coupler. The filtering device also includes an optical resonator and a third optical coupler optically coupling the optical resonator to the second optical waveguide.

Abstract: A cascaded interleaver includes at least three two-stage Fourier filters. A first of the Fourier filters includes first and second waveguides such that the first waveguide has a longer optical path length than the second waveguide. A second of the Fourier filters includes third and fourth waveguides such that the third waveguide has a longer optical path length than the fourth waveguide. A third of the Fourier filters has fifth and sixth waveguides such that the fifth waveguide has a longer optical path length than the sixth waveguide. The third waveguide has an input coupled to an output of the first waveguide and the fifth waveguide has an input coupled to an output of the second waveguide. At least one of the Fourier filters include at least three couplers alternating with a delay path between adjacent ones of the couplers. A second of the couplers is of an order different from a first and third of the couplers.

Abstract: Achromatic phase-matching (APM) is used for efficiently multiplying the frequency of broad bandwidth light by using a nonlinear optical medium comprising a second-harmonic generation (SHG) crystal. Stationary optical elements whose configuration, properties, and arrangement have been optimized to match the dispersion characteristics of the SHG crystal to at least the second order. These elements include a plurality of prismatic elements for directing an input light beam onto the SHG crystal such that each ray wavelength is aligned to match the phase-matching angle for the crystal at each wavelength of light to at least the second order and such that every ray wavelength overlap within the crystal.