Abstract: An illumination module may provide light in a plurality of colors including Red-Green-Blue (RGB) light and/or white light. The light from the illumination module may be directed to a 3LCD system, a Digital Light Processing (DLP®) system, a Liquid Crystal on Silicon (LCoS) system, or other micro-display or micro-projection systems. In one embodiment the illumination module includes a laser configured to produce an optical beam at a first wavelength, a planar lightwave circuit coupled to the laser and configured to guide the optical beam, and a waveguide optical frequency converter coupled to the planar lightwave circuit and configured to receive the optical beam at the first wavelength, convert the optical beam at the first wavelength into an output optical beam at a second wavelength, and may provide optically coupled feedback which is nonlinearly dependent on a power of the optical beam at the first wavelength to the laser.

Abstract: Optical waveguide devices characterized by low loss for a fundamental mode and high loss for higher order modes are disclosed. The high loss is sufficiently high that the waveguide is effectively single-moded.

Abstract: Quasi-phasematching design to provide an approximation to a desired spectral amplitude response A(f) is provided. An initial phase response ?(f) corresponding to A(f) is generated. Preferably, d2?(f)/df2 is proportional to A2(f). Alternatively, ?(f) can be a polynomial in f. A function h(x) is computed such that h(x) and H(f)=A(f)exp(i?(f)) are a Fourier transform pair. A domain pattern function d(x) is computed by binarizing h(x) (i.e., approximating h(x) with a constant-amplitude approximation). In some cases, the response provided by this d(x) is sufficiently close to A(f) that no further design work is necessary. In other cases, the design can be iteratively improved by modifying ?(f) responsive to a difference between the desired response A(f) and the response provided by domain pattern d(x). Various approaches for binarization are provided. The availability of multiple binarization approaches is helpful for making design trades (e.g.

Abstract: Quasi-phasematching design to provide an approximation to a desired spectral amplitude response A(f) is provided. An initial phase response ?(f) corresponding to A(f) is generated. Preferably, d2?(f)/df2 is proportional to A2(f). Alternatively, ?(f) can be a polynomial in f. A function h(x) is computed such that h(x) and H(f)=A(f)exp(i?(f)) are a Fourier transform pair. A domain pattern function d(x) can be computed by binarizing h(x) (i.e., approximating h(x) with a constant-amplitude approximation). In some cases, the response provided by this d(x) is sufficiently close to A(f) that no further design work is necessary. In some embodiments of the invention, the need for binarization can be reduced or eliminated by providing amplitude modulation of the effective nonlinearity.

Abstract: Wavelength combining for nonlinear frequency conversion is provided having nonlinear feedback to the sources being combined. Power that is fed back to the sources is obtained from within a wavelength conversion device. Therefore, the feedback power to a source has a nonlinear dependence on input power provided by that source to the wavelength conversion device. Such nonlinear feedback can advantageously reduce the sensitivity of the output power from the wavelength conversion device to variations in the nonlinear coefficients of the conversion device. The reason for this reduced sensitivity is that in preferred embodiments, the feedback power increases if a nonlinear coefficient decreases. This increased feedback tends to increase the power supplied to the conversion device, thus mitigating the effect of the reduced nonlinear coefficient.

Abstract: Quasi-phasematching design to provide an approximation to a desired spectral amplitude response A(f) is provided. An initial phase response ?(f) corresponding to A(f) is generated. Preferably, d2?(f)/df2 is proportional to A2(f). A function h(x) is computed such that h(x) and H(f)=A(f)exp(i?(f)) are a Fourier transform pair. A domain pattern function d(x) is computed by binarizing h(x) (i.e., approximating h(x) with a constant-amplitude approximation). In some cases, the response provided by this d(x) is sufficiently close to A(f) that no further design work is necessary. In other cases, the design can be iteratively improved by modifying ?(f) responsive to a difference between the desired response A(f) and the response provided by domain pattern d(x). Various approaches for binarization are provided. The availability of multiple binarization approaches is helpful for making design trades (e.g., in one example, fidelity to A(f) can be decreased to increase efficiency and to increase domain size).