Optical waveguides – With optical coupler – Input/output coupler
Reexamination Certificate
1999-10-25
2001-04-10
Lee, John D. (Department: 2874)
Optical waveguides
With optical coupler
Input/output coupler
C372S020000, C372S102000, C385S027000, C385S040000, C385S129000
Reexamination Certificate
active
06215928
ABSTRACT:
The present invention relates to electro-optically controlled optical elements generally and also to electro-optical assemblies including such elements.
Various types of electro-optically controlled optical elements are known in the art. U.S. Pat. Nos. 5,157,537 and 5,337,183 describe examples of such elements. The elements described in U.S. Pat. Nos. 5,157,537 and 5,337,183 have limited dynamic range and are thus proposed to be employed as optical modulators.
The present invention seeks to provide electro-optically controlled optical elements having a significantly greater dynamic range than is known from the prior art.
There is thus provided in accordance with a preferred embodiment of the present invention an electro-optically controlled optical element including a diffraction grating and a planar waveguide associated with the diffraction grating, the diffraction grating and planar waveguide being configured to undergo resonance of at least one of transmitted or reflected light at a wavelength which is selectable by means of an electrical input.
The planar waveguide may include multiple layers having differing indices of refraction.
The element may have at least one light transmissive surface generally parallel to the planar waveguide and including an anti-reflection coating formed on at least one light transmissive surface.
There is also provided in accordance with a preferred embodiment of the present invention a laser including a laser cavity, an active tunable mirror and an output coupler defining the laser cavity, and wherein
the active tunable mirror includes an electro-optically controlled optical element including:
a diffraction grating; and
a planar waveguide associated with the diffraction grating, the diffraction grating and planar waveguide being configured to undergo resonance of at least one of transmitted or reflected light at a wavelength which is selectable by means of an electrical input.
There is additionally provided in accordance with a preferred embodiment of the present invention an electro-optically tunable laser which is tunable over a dynamic range of more than 0.1 nanometer, preferably more than 1 nanometer and even more preferably several tens of nanometers.
The optical element may function as an electro-optical tunable filter.
In accordance with a preferred embodiment of the present invention, the electro-optically controlled optical element also includes a planar waveguide whose index of refraction is controlled by the electrical input.
Additionally or alternatively, the electro-optically controlled optical element also includes a light transmissive medium whose index of refraction is controlled by the electrical input. The light transmissive material may be a liquid crystal material.
In accordance with a preferred embodiment of the present invention, the electro-optically controlled optical element also includes transparent conductors arranged adjacent the planar waveguide and electro-optically connected via electrodes to the electrical input, the transparent conductors being operative to apply electrical energy across the planar waveguide.
Additionally or alternatively, the electro-optically controlled optical element also includes transparent conductors arranged adjacent the light transmissive medium and electro-optically connected via electrodes to the electrical input, the transparent conductors being operative to apply electrical energy across the light transmissive medium.
In accordance with one embodiment of the present invention, the diffraction grating and the planar waveguide are formed of semiconductor materials. Preferably, also includes a planar waveguide whose index of refraction is controlled by the electrical input and also including transparent conductors arranged adjacent the planar waveguide and electro-optically connected via electrodes to the electrical input, the transparent conductors being operative to apply electrical energy via suitably doped semiconductor material across the planar waveguide.
Additionally or alternatively, the element also includes a light transmissive medium whose index of refraction is controlled by the electrical input and transparent conductors arranged adjacent the light transmissive medium and electro-optically connected via electrodes to the electrical input, the transparent conductors being operative to apply electrical energy via suitably doped semiconductor material across the light transmissive medium.
In accordance with a preferred embodiment of the present invention, at least one of the diffraction grating and the planar waveguide are formed of an electro-optical material. Preferably, the planar waveguide has an index of refraction which is controlled by the electrical input and also including transparent conductors arranged adjacent the planar waveguide and electro-optically connected via electrodes to the electrical input, the transparent conductors being operative to apply electrical energy across the planar waveguide.
Alternatively or additionally, the element also includes a light transmissive medium whose index of refraction is controlled by the electrical input and transparent conductors arranged adjacent the light transmissive medium and electro-optically connected via electrodes to the electrical input, the transparent conductors being operative to apply electrical energy across the light transmissive medium.
In accordance with a preferred embodiment of the invention at least one of the diffraction grating and the planar waveguide are formed of a polymeric material having a range of selectable indices of refraction which is relatively wide.
Preferably, the planar waveguide has an index of refraction which is controlled by the electrical input and also including transparent conductors arranged adjacent the planar waveguide and electro-optically connected via electrodes to the electrical input, the transparent conductors being operative to apply electrical energy across the planar waveguide.
Alternatively or additionally, the element also includes a light transmissive medium whose index of refraction is controlled by the electrical input and transparent conductors arranged adjacent the light transmissive medium and electro-optically connected via electrodes to the electrical input, the transparent conductors being operative to apply electrical energy across the light transmissive medium.
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Delorme, F. et al, “Butt-Joined DBR Laser with 15 NM Tunability Grown in Three MOVPE Steps”,Electronic Letters,GB, IEE Stevenage, vol. 31, No. 15, Jul. 20, 1995, pp. 1244-1245, XP000525768.
Bryan-Brown. G.P. et al., “Grating Coupled Liquid Crystal Waveguides Using Nematics and Smetics”,J. of Applied Physics, vol. 73, No. 8, Apr. 15, 1993, pp. 3603-3607.
Friesem Asher A.
Sharon Avner Zvi
Darby & Darby
Lee John D.
Yeda Research and Development Co. Ltd.
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