The present invention is related to phased arrays, and more particularly to an integrated optical phase array.
Optical storage devices such as CD ROMs benefit from a compact high resolution optical beam steering array. Other examples of existing and emerging applications for optical phased arrays include Light Detection and Ranging (LIDAR), optical radar, free space optical communication (including deep space communication), optical imaging, laser based welding and cutting, optical sensing, focal length adjustment, games, scanning systems, spectroscopy, and fully or partially integrated laser based projection systems for portable and non-portable devices.
Unlike electrical phased arrays, the emitting elements of an optical phased-array are often placed multiple wavelength apart to compensate, for example, for small wavelength of light and routing challenges. A relatively large spacing between the emitting elements of an optical phased-array results in the presence of undesired side lobes in the far-field pattern, thereby limiting the steering range, and undesirable beam-width effect.
An optical phase array, in accordance with one embodiment of the present invention, includes, in part, N optical signal emitting elements, and N lenses each associated with a different one of the N optical signal emitting elements and positioned to form an image of its associated signal emitting element. N is an integer greater than 1. In one embodiment, each of at least a subset of the N optical signal emitting elements is a grating coupler. In one embodiment, of at least a subset of the N optical signal emitting elements is an edge coupler.
In one embodiment, each of at least a subset of the N lenses is formed from Silicon. In one embodiment, the optical phased array further includes, in part, a concave lens positioned between the N signal emitting elements and the N lenses. In one embodiment, the optical phased array further includes, in part, a convex lens positioned between the N signal emitting elements and the N lenses.
In one embodiment, the N optical signal emitting elements are formed in a silicon dioxide layer formed above a semiconductor substrate and the N lenses are formed from Silicon disposed above the silicon dioxide layer. In one embodiment, the N optical signal emitting elements are formed in a silicon dioxide layer formed above a semiconductor substrate, and the N lenses and the concave lens are formed from Silicon disposed above the silicon dioxide layer. In one embodiment, the N optical signal emitting elements are formed in a silicon dioxide layer formed above a semiconductor substrate, and the N lenses and the convex lens are formed from Silicon disposed above the silicon dioxide layer. In one embodiment, the N optical signal emitting elements receive an optical signal generated by the same source.
A method of generating a far-field radiation pattern, in accordance with one embodiment of the present invention, includes, in part, generating N optical signals each from a different one of N emitting elements, and directing the N optical signals toward N lenses each associated with a different one of the N optical signal emitting elements and positioned to form an image of the associated optical signal emitting element. N is an integer greater than 1.
In one embodiment, each of at least a subset of the N optical signal emitting elements is a grating coupler. In one embodiment, each of at least a subset of the N optical signal emitting elements is an edge coupler. In one embodiment, each of at least a subset of the N lenses is formed from Silicon.
In one embodiment, the method further includes, in part, positioning a concave lens between the N signal emitting elements and the N lenses. In one embodiment, the method further includes, in part, positioning a convex lens between the N signal emitting elements and the N lenses.
In one embodiment, the N optical signal emitting elements are formed in a silicon dioxide layer formed above a semiconductor substrate and the N lenses are formed from Silicon disposed above the silicon dioxide layer. In one embodiment, the N optical signal emitting elements are formed in a silicon dioxide layer formed above a semiconductor substrate, and the N lenses and the convex lens are formed from Silicon disposed above the silicon dioxide layer. In one embodiment. The N optical signal emitting elements are formed in a silicon dioxide layer formed above a semiconductor substrate, and the N lenses and the concave lens are formed from Silicon disposed above the silicon dioxide layer. In one embodiment, the method further includes, in part, supplying an optical signal to each of the N optical signal emitting from the same optical signal source.
The present application contains at least one drawing executed in color. Copies of this patent application with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
where E0, n, and Ø are respectively the electric field constant, element index, and the constant phase difference between adjacent elements.
Applying the Fraunhofer far field approximation, the far field intensity of the electric field at distance z=L may be determined using the following:
where and represents the 2D Fourier transform, respectively. Expression (2) may be further simplified to:
As is seen from expression (3), the electric field intensity of at any point L may be varied by varying Ø, which is the difference between phases of adjacent beams. The Fourier transform of the profile of the individual beams defines the envelope (proportional to
within which the beam may be steered.
Due to finite size of the optical phased array 50 and periodic nature of G(Ω), side lobes appear in the far field pattern. The position of the main lobe and the position of its adjacent side lobes may be calculated from Expression 3. The ratio between the main lobe and the adjacent side lobe, commonly referred to as the side lobe suppression ratio (SLSR), may be calculated using the following expression:
Using Expressions 3 and 4, the maximum steering angle for a given SLSR may be substantially defined as:
In accordance with one embodiment of the present invention, each beam emitting element of an optical phased array, such as grating coupler, an edge coupler, or the like, includes a beam enhancing element so as to increase the ratio
as shown in Equation (5), and thereby increase the steering angle of the optical phased array.
Associated with each emitting element 160i is a concave lens 170i. Only 4 of the lenses, namely 1701, 1702, 1703 and 1704 that are associated respectively with emitting elements 1601, 1602, 1603 and 1604 are shown in
Also disposed in optical phased array 250 is a concave optical lens 180 positioned at more than twice its focal length away from images 165i. Optical lens 180 thus causes images 185i to be formed at its focal line as shown in
Also disposed in optical phased array 300 is a convex optical lens 188 having a focal point longer than images 165i. Optical lens 188 thus causes images 185i to be formed at its focal line as shown in Figure A. Only four of the images 1851, 1852, 1853 and 1854 are shown in
Therefore, in accordance with embodiments of the present invention, using optical enhancement elements, either the effective width of an emitting element is increased, or the effective distance between each pair of adjacent emitting elements is decreased so as to increase the steering angle of the optical phased array. It is understood that an optical phased array, in accordance with the embodiment of the present invention may be formed in a substrate using conventional opto-electronics or photonics semiconductor processes.
An optical phased-array, in accordance with embodiments of the present invention, may be formed using a two-dimensional planar phased array in visible range or even invisible range when the phased array is adapted to perform frequency conversion. Multiple planar arrays emitting at different wavelengths may be stacked vertically to perform color combining per pixel thereby to form a projected colored image or video, in accordance with embodiments of the present invention. Moreover, in accordance with embodiments of the present invention, planar two-dimensional optical phased arrays may be tiled to form larger arrays or form a three dimensional image, video, or object in the space.
The above embodiments of the present invention are illustrative and not limitative. Embodiments of the present invention are not limited by the type of optical signal emitting element or lens disposed in a phased array. Embodiments of the present invention are not limited by the number of grooves in an optical grating coupler when optical gratings are used as optical signal emitting elements. Embodiments of the present invention are not limited by the wavelength of the optical signal, nor are they limited by the type of substrate, semiconductor or otherwise, in which the optical phased array may be formed. Embodiments of the present invention are not limited by the number of arrays used to form a two-dimensional array or the number of two-dimensional arrays used to a form a stack of three-dimensional array. Other additions, subtractions or modifications are obvious in view of the present disclosure and are intended to fall within the scope of the appended claims.
The present application claims benefit under 35 U.S.C. 119 (e) of U.S. provisional application No. 62/405,423, filed Oct. 7, 2016, entitled “Integrated Optical Phased Arrays with Optically Enhanced Elements”, the content of which is incorporated herein by reference in its entirety.
Number | Name | Date | Kind |
---|---|---|---|
4686533 | MacDonald et al. | Aug 1987 | A |
4833336 | Kraske | May 1989 | A |
6424442 | Gfeller et al. | Jul 2002 | B1 |
6894550 | Trosa et al. | May 2005 | B2 |
7313295 | Ghandi et al. | Dec 2007 | B2 |
7539418 | Krishnamoorthy et al. | May 2009 | B1 |
7623783 | Morris et al. | Nov 2009 | B2 |
8244134 | Santori et al. | Aug 2012 | B2 |
8311417 | Poggiolini et al. | Nov 2012 | B1 |
9325419 | Kato | Apr 2016 | B1 |
9557585 | Yap | Jan 2017 | B1 |
10382140 | Fatemi et al. | Aug 2019 | B2 |
10795188 | Aflatouni et al. | Oct 2020 | B2 |
20020174660 | Venkatasubramanian | Nov 2002 | A1 |
20020181058 | Ger et al. | Dec 2002 | A1 |
20030090775 | Webb et al. | May 2003 | A1 |
20040071386 | Nunen et al. | Apr 2004 | A1 |
20040101227 | Takabayashi et al. | May 2004 | A1 |
20040141753 | Andreu-von Euw et al. | Jul 2004 | A1 |
20050084213 | Hamann et al. | Apr 2005 | A1 |
20050138934 | Weigert et al. | Jun 2005 | A1 |
20060034609 | Morris et al. | Feb 2006 | A1 |
20060056845 | Parsons et al. | Mar 2006 | A1 |
20080111755 | Haziza et al. | May 2008 | A1 |
20080181550 | Earnshaw | Jul 2008 | A1 |
20090297092 | Takahashi | Dec 2009 | A1 |
20100054653 | Carothers | Mar 2010 | A1 |
20100158521 | Doerr et al. | Jun 2010 | A1 |
20100187402 | Hochberg | Jul 2010 | A1 |
20100226658 | Fujimoto et al. | Sep 2010 | A1 |
20110052114 | Bernasconi | Mar 2011 | A1 |
20110064415 | Williams et al. | Mar 2011 | A1 |
20120087613 | Rasras | Apr 2012 | A1 |
20120207428 | Roelkens | Aug 2012 | A1 |
20120213531 | Nazarathy et al. | Aug 2012 | A1 |
20130107667 | Boufounos | May 2013 | A1 |
20150009068 | Gregoire et al. | Jan 2015 | A1 |
20150198713 | Boufounos et al. | Jul 2015 | A1 |
20150336097 | Wang et al. | Nov 2015 | A1 |
20150357710 | Li et al. | Dec 2015 | A1 |
20160170141 | Luo et al. | Jun 2016 | A1 |
20160172767 | Ray | Jun 2016 | A1 |
20160266414 | Gill et al. | Sep 2016 | A1 |
20160276803 | Uesaka | Sep 2016 | A1 |
20160285172 | Kishigami et al. | Sep 2016 | A1 |
20170041068 | Murakowski et al. | Feb 2017 | A1 |
20170131576 | Gill et al. | May 2017 | A1 |
20170279537 | Kim | Sep 2017 | A1 |
20170315387 | Watts et al. | Nov 2017 | A1 |
20170324162 | Khachaturian et al. | Nov 2017 | A1 |
20180123699 | Fatemi et al. | May 2018 | A1 |
20180101032 | Aflatouni et al. | Jun 2018 | A1 |
20180173025 | McGreer et al. | Jun 2018 | A1 |
20190056499 | Fatemi et al. | Feb 2019 | A1 |
20190089460 | Khachaturian et al. | Mar 2019 | A1 |
Number | Date | Country |
---|---|---|
3094987 | Dec 2018 | EP |
WO 2018148758 | Aug 2018 | WO |
WO 2018165633 | Sep 2018 | WO |
Entry |
---|
U.S. Appl. No. 15/616,844, Non-Finai Office Action dated Jun. 1, 2018. |
WIPO Application No. PCT/US2018/018070, PCT International Search Report and Written Opinion of the International Searching Authority dated Apr. 27, 2018. |
WIPO Application No. PCT US2018/021882, PCT International Search Report and Written Opinion of the International Searching Authority dated Jun. 7, 2018. |
U.S. Appl. No. 15/728,329, Non-Final Office Action dated Jan. 19, 2018. |
U.S. Appl. No. 15/728,329, Response to Final Office Action filed Jan. 16, 2019. |
U.S. Appl. No. 15/616,844, Response to Non-Final Office Action filed Dec. 3, 2018. |
U.S. Appl. No. 15/728,329, Final Office Action dated Aug. 3, 2018. |
U.S. Appl. No. 15/728,329, Response to Non-Final Office Action filed Jul. 18, 2018. |
U.S. Appl. No. 15/587,391, Non-Final Office Action dated Dec. 13, 2018. |
Bliss, et al., “Muitipie-Input Multiple-Output (MIMO) Radar and Imaging: Degrees of Freedom and Resolution,” Signals, Systems, and Computers (Asilomar) Conference, pp. 54-59, (2003). |
Bogaerts, et al., “Low-loss, low-cross-talk crossings for silicon-on-insulator nanophotonic waveguides,” Optics Letters, 32(19): 2801-2803, (2007). |
Katz, et al., “Diffraction coupled phase-locked semiconductor laser array,” Appl. Phys. Lett., 42(7): 554-556, (1983). |
Liang, et al., “Tiled-aperture coherent beam combining using optical phase-lock loops,” Electronics Letters, 44(14), (2008). |
Resler, et al., “High-efficiency liquid-crystal optical phased-array beam steering,” Opt. Lett., 21(9): 689-691, (1996). |
Vaidyanathan, et al., “Sparse sensing with coprime arrays,” Signals, Systems, and Computers (Asilomar) Conference, pp. 1405-1409, (2010). |
U.S. Appl. No. 15/728,329, Non-Final Office Action dated Jan. 30, 2019. |
U.S. Appl. No. 15/587,391, Final Office Action dated Aug. 15, 2019. |
U.S. Appl. No. 15/616,844, Notice of Allowance dated Mar. 27, 2019. |
U.S. Appl. No. 15/728,329, Non-Final Office Action dated Sep. 9, 2019. |
U.S. Appl. No. 15/917,536, Non-Final Office Action dated Aug. 7, 2019. |
U.S. Appl. No. 15/917,536, Requirement for Restriction/Election dated Feb. 11, 2019. |
WIPO Application No. PCT/US2018/018070, PCT International Preliminary Report on Patentability dated Aug. 13, 2019. |
WIPO Application No. PCT/US2018/021882, PCT International Preliminary Report on Patentability dated Sep. 10, 2019. |
U.S. Appl. No. 15/587,391, Non-Final Office Action dated Mar. 19, 2020. |
U.S. Appl. No. 15/896,005, Ex Parte Quayle Action mailed Apr. 29, 2020. |
U.S. Appl. No. 15/917,536, Final Office Action dated May 14, 2020. |
U.S. Appl. No. 15/728,329, Notice of Allowance dated Jun. 12, 2020. |
EP 18764449.7 Extended Suroepean Search Report dated Nov. 24, 2020. |
U.S. Appl. No. 15/971,536, Non-Final Office Action dated Nov. 25, 2020. |
Number | Date | Country | |
---|---|---|---|
20180101083 A1 | Apr 2018 | US |
Number | Date | Country | |
---|---|---|---|
62405423 | Oct 2016 | US |