Efficient Bragg-like operation of intracavity low-efficiency plane gratings

Abstract

The diffraction regime of a thin grating inserted in a Fabry-Perot cavity is investigated. Our calculations show that, at Bragg incidence, a single diffraction order can be selectively enhanced, giving rise to a very efficient Bragg-like diffraction regime. The optimization of the device is studied as a function of the resonator thickness and finesse and the grating position inside the Fabry-Perot cavity. The angular and wavelength selectivities are also investigated. The device could be easily integrated and would be very useful for optical signalprocessing applications.

Bragg diffraction in thin 2D refractive index modulated semiconductor samples

“…The thickness is also an issue as it must not be too large if an integrated device is wanted, although the diffraction regime associated with thin crystals is a Raman-Nath regime involving multiple diffracted beams. Besides the already wellknown simple [2][3][4] and double resonance [5][6][7][8][9] in a Fabry-Perot cavity, a new approach using slow light at the band edge of a one-dimensional photonic crystal (1D-PC) was recently demonstrated to overcome these difficulties, first in photopolymers [10] and then in semiconductor Bragg reflectors [11]. Results are especially attractive in the latter case due to the high index contrast of Bragg reflectors.…”

Efficient Bragg diffraction in thin semiconductor two-dimensional gratings

“…However, their small thicknesses imply a Raman-Nath diffraction regime with several diffraction orders, which limits the maximum power reached in the desired order. Such a drawback was circumvented by placing the holographic material in an asymmetric cavity [6][7][8], and the Bragg operation of the device was obtained, even with a thin recording material [9,10]. Recently, another solution using two-dimensional (2D) photonic crystals was proposed and demonstrated in photopolymers [11].…”

Band-edge-induced Bragg diffraction in two-dimensional photonic crystals

“…It was recently demonstrated that placing a nonlinear material in a cavity was a good way to enhance both the diffraction efficiency and the angular selectivity of the device, 6,7 and to reach the Bragg diffraction regime with only one diffraction order even with a thin nonlinear material. 8,9 However, by using such a device, many diffraction peaks are obtained when one varies the wavelength of the read beam. These peaks are due to the coupling of light with different Fabry-Perot modes.…”