Jean Pierre Huignard

Dual-Frequency Laser at 1.5

We describe the stabilization of the beatnote of an Er,Yb:glass dual-frequency laser at 1.5 mum with and without an external microwave reference. In the first case, a classical optical phase-locked loop (OPLL) is used, and absolute phase noise levels as low as -117 dBrad2/Hz at 10 kHz from the carrier are reported. In the second case one or two fiber-optic delay lines are used to lock the frequency of the beatnote. Absolute phase noise levels as low as -107 dBrad2/Hz at 10 kHz from the carrier are measured, fairly independant of the beatnote frequency varying from 2 to 6 GHz. An analysis of the phase noise level limitation is presented in the linear servo-loop theory framework. The expected phase noise level calculated from the measurement of the different noise sources fits well with the predictions.

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Projection systems based on liquid-crystal displays (LCDs) offer new opportunities to display high-definition and large-size TV images. There are two types of LCD projector architectures: the 3-LCD architecture uses one LCD for each primary color, red, green, and blue, whereas a single-LCD configuration employs only one LCD paved with color filters. The single-LCD projector is simple and compact but suffers from a poor luminous efficiency because of losses in the color filters: each filter transmits only ~1/3 of the flux emitted by the lamp. To increase this optical efficiency, we propose to introduce volume holographic elements in the architecture of a single-LCD projector. Innovative systems are presented in which volume holographic elements realize the spatiochromatic illumination of the LCD. This illumination consists of selectively directing all the light that corresponds to a primary color, red, green, or blue, in the pixel addressed with the corresponding video composite signal and exploits the spectral selectivity and dispersion properties of volume holographic gratings and lenses. The two main advantages of such illumination are the suppression of the color filters and the recovery of the light lost in a classical architecture by absorption of the color filters. A complete luminous efficiency analysis of spatiochromatic illumination with volume holographic elements is presented. The achieved performances are compared with classical single-LCD projectors.

m for Optical Distribution and Generation of High-Purity Microwave Signals

We propose, analyze and experimentally demonstrate the amplification and detection of microwave signals transmitted on dual frequency optical carriers, using two wave mixing with differential gain in BaTiO3.

Phase volume holographic optical components for high-brightness single-LCD projectors.

We have demonstrated self-diffraction of femto-second Laguerre Gaussian modes for the first time. Experimental diffraction efficiency of ~9% was obtained. Addition of angular momentum was also seen in diffraction beam.

Coherent detection of optically carried microwave signals through two-wave mixing in a BaTiO 3 crystal

Coherent optics offers very unique advantages for information processing and transmission with a high parallelism and a strong data rate. The implementation of these idea requires non linear materials permitting efficient interactions between optical beams.