• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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  • 优先权
    • 专利摘要:
    Waveguide, method of manufacturing said waveguide and polarization divider that makes use of said waveguide. Waveguide and polarization divider based on said waveguide, in which a rotation of an angle greater than zero is applied to a plurality of sections of a core material and a plurality of sections of a covering material, thus achieving an independent control of the refractive indices of a zero-order electrical transverse mode and a zero-order magnetic transverse mode. This document also describes a method of manufacturing said waveguide that allows modifying the birefringence of the light flowing through it. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2736899A1
    申请号:ES201830653
    申请日:2018-06-29
    公开日:2020-01-08
    发明作者:Robert Halir；González José Manuel Luque；Bermello Alaine Herrero；Moñux Alejandro Ortega；Fernández Iñigo Molina；Pérez Juan Gonzalo Wangüemert；Velasco Aitor Villafranca
    申请人:Consejo Superior de Investigaciones Cientificas CSIC；Universidad de Malaga；
    IPC主号:
    专利说明:

    [0001]
    [0002]
    [0003]
    [0004] Object of the invention
    [0005]
    [0006] The present invention relates to the field of integrated optics, and more specifically to devices based on waveguides with sub-wavelength structures.
    [0007]
    [0008] Background of the invention
    [0009]
    [0010] The birefringence of photonic platforms, that is, the difference in behavior of waveguide-based devices between electrical transverse polarization (TE) and magnetic transverse polarization (TM), is one of the great challenges for development and expansion of integrated optics. In particular, there are two main ways to deal with this problem: make independent polarization structures (that is, with the same effective index and / or dispersive characteristics for TE and TM) or develop polarization division devices (that is, which separate the TE and TM modes into two output guides, then processed independently, or discarding one of them).
    [0011]
    [0012] Regardless of the alternative followed (independence of polarization or polarization selectivity), the difficulty arises when handling the birefrigence of the waveguides used, either to match the response of the TE and TM modes or to make it so disparate that Allow for separation. In general, given the design limitations obtainable by geometric modification of a single material and engraving depth, most solutions in the state of the art are based on the incorporation of additional materials to the core material of the waveguide, or to the use of structures with multiple layers or depths of engraving. However, these alternatives significantly increase the manufacturing complexity of the devices.
    [0013]
    [0014] For example, US 5,090,790 presents a first waveguide independent of polarization in which multiple layers of quantum wells are introduced into the guide to control its birefringence. In a second example, US 2003/174982 A1 presents a waveguide independent of the alternative polarization in which an electro-optical coverage is deposited, controlled by a set of electrodes that generate a modified electric field around the core of the guide, whose active control allows indexes to be equalized TE and TM modes. As can be seen, in both cases it is necessary to resort to complex manufacturing and control processes, requiring non-realizable materials and geometries with single exposure manufacturing systems.
    [0015]
    [0016] As for polarization dividers, various phenomena, materials and optical structures have been proposed in order to implement said polarization dividers. Among the proposed alternatives, the sub wavelength diffraction networks, the photonic crystals, the negative refraction present in these crystals or the birefringence of form (intrinsic of the materials) are worth mentioning. However, all these configurations present serious problems when they are manufactured, either due to a high sensitivity to deviations from the nominal designs, inevitable during the manufacturing process, or by requiring geometries or auxiliary elements that cannot be implemented by the usual manufacturing procedures for commercial photonic chips.
    [0017]
    [0018] One possible solution to the mentioned man-made limitations is the use of multimodal interference couplers (MMI ). For example, US 5,838,842 presents an MMI for polarization division in integrated devices. The MMI has a region of multimode waveguide (better known by its English name, " slab ") in which auto-images of the electric transverse (TE) and magnetic transverse (TM) modes at different lengths are generated.These lengths are determined by the differences in the propagation constants of both modes in the multimode waveguide region, however, since the multimode waveguide region is a continuous waveguide, the differences between the propagation constants are small and poorly controllable, resulting in devices poorly efficient and requiring high propagation distances in the multimode waveguide region, assuming Both a high overall device size.
    [0019]
    [0020] Note that multimodal interference (MMI) couplers have also been conventionally used for power division, that is, instead of separating two polarizations into two output waveguides, they separate part of the power of a single polarization in two or more output waveguides. The performance of MMIs as power dividers, and in particular their losses and bandwidth, has been improved by the use of sub-wavelength structures (hereinafter SWG, for its acronym "Sub-Wavelength grating"), as presented in ES 2,379,058. Note that the SWG structures of said power divider, in addition to being perpendicular to the input and output waveguides, are designed to operate in a wide bandwidth at a single polarization. That is, the geometric parameters of said SWG structure are selected so that the bandwidth of the device is optimized to a polarization, the device being inoperative to orthogonal polarization. In particular, the birefringence of the multimode waveguide region implies different beat lengths for the TE and TM polarizations, whereby the positions of the MMI in which the power division is verified are different for each polarization, preventing their extraction joint. That is, in this type of devices, the birefringence and anisotropy of the SWG structure are not controllable during design, but are a consequence of their geometric parameters.
    [0021]
    [0022] Another possible alternative is the directional couplers, in which there is a lateral coupling between two adjacent single-mode guides. However, for this coupling to be selective in polarization, and not a mere power division (that is, to only affect the TE or TM mode, while the other mode continues to propagate without alterations in the waveguide by which has been introduced), it is still necessary to control the birefringence of at least one of the single-mode guides that comprise it. Said control can be carried out by the deposition of additional materials and / or active elements, with the aforementioned disadvantages that said option entails or, as exemplified by CN 106,959,485 A, by the use of SWG structures.
    [0023]
    [0024] In the case of CN 106,959,485 A, the SWG structure is engraved on one side of one of the single-mode guides, by means of slits perpendicular to the direction of light propagation that only partially occupy the core of said guide. However, this geometry provides very limited control of the birefringence of the guide, since the effects on the TE and TM modes of the structure remain linked to each other. This limitation when implementing the effective indices of the TE and TM modes independently translates into reduced performance in terms of insertion loss, extinction ratio and bandwidth. Additionally, the response of this structure can only be adjusted by modifying its period and duty cycle, which may affect the minimum feature size of the device (from the English "minimum feature size") and therefore does not affect its manufacturing difficulty.
    [0025]
    [0026] Ultimately, there is still a need in the prior art for waveguide structures capable of providing efficient, compact and high bandwidth polarization control, without increasing the manufacturing complexity of the devices.
    [0027]
    [0028] Description of the invention
    [0029]
    [0030] The present invention solves the problems described above by means of a single-mode guide with a SWG structure that is rotated with an angle of rotation with respect to the direction of propagation of the guided light, which allows modifying the birefringence properties of said guide. The single-mode guide described here can be integrated together with any other combination of devices on a photonic chip, and can be manufactured during the same exposure step as the rest of said devices (unlike other independent polarization guides or polarization dividers that require multiple recording depths, sloping walls, additional materials, etc).
    [0031]
    [0032] In a first aspect of the invention a modified birefringence guiding device is presented, meaning "modified birefrigence" not a real-time control of the birefringence of the waveguide, but a constant alteration of said birefringence with respect to that of a traditional continuous waveguide, said alteration being controllable during a previous phase of guide design by selecting the geometric properties thereof, and in particular, from an angle of a SWG structure. The modified birefringence guidance device makes use of a modified birefringence waveguide, therefore comprising a SWG structure, formed by an alternate arrangement of a plurality of sections of a core material and a plurality of sections of cover material , with a period less than the wavelength of the light guided by said modified birefringence waveguide. In particular, the SWG structure is rotated an angle greater than zero with respect to the direction of light propagation. That is, the interfaces between the sections of the covering material and the sections of the core material have said angle with a plane perpendicular to the axis of light propagation Said angle allows independent control of a first effective index for the zero-order electrical transverse mode and a second effective index for the zero-order magnetic transverse mode.
    [0033]
    [0034] Note that, although other SWG geometric parameters such as the period or the filling factor can affect the resulting anisotropy or birefringence, this effect is significantly less than that produced by the rotation of the interfaces, thus limiting the benefits obtainable by the divider Also, note that, unlike these parameters (period and filling factor), the angle of rotation does not affect the minimum feature size of the device (from the English "minimum feature size ") and therefore does not increase its manufacturing difficulty.
    [0035]
    [0036] Note also that the specific angle for which a certain characteristic related to birefringence is obtained (for example, a specific condition between the first effective index for the zero-order electric transverse mode and the second effective index for the magnetic order transverse mode zero), depends on the rest of the material and morphological characteristics of the guide, such as its height, width, core material, cover material, SWG period and SWG filling factor. Therefore, said specific angle is preferably determined in a previous design phase according to the method of the third aspect of the present invention.
    [0037]
    [0038] Preferably, said concrete conditions obtained by selecting the angle of rotation of the SWG structure can comprise both an independent polarization behavior (i.e. the same value for the first effective index of the zero-order electrical transverse mode and for the second effective index of the zero-order magnetic transverse mode) as a selective polarizing behavior (that is, a significantly different value for the first effective index of the zero-order electrical transverse mode and for the second effective index of the zero-order magnetic transverse mode.
    [0039]
    [0040] Also preferably, depending on the particular embodiment, the geometric parameters (width, period, filling factor, angle) of the SWG structure of the modified birefringence waveguide may either remain constant throughout the entire guideline, or be modified. gradually or abruptly along said guide, thus obtaining different birefringent properties in different positions of the guide.
    [0041]
    [0042] The geometry of the core material sections may also vary between implementations. In particular, three preferred options include:
    [0043] - One segment for each section, completely separated from each other by the cover material. Preferably, each segment has a mostly rectangular or trapezoidal shape (seen on a plane parallel to an interface between a layer of core material and a layer of support material).
    [0044] - Multiple segments for each section, each pair of segments of the same section being separated by a slit or channel of the covering material.
    [0045] - Sections connected to each other by a plurality of central joints of the core material, either of constant width, or of varying width.
    [0046]
    [0047] The modified birefringence waveguide is preferably implemented in silicon on insulator (SOI ), with a cover material preferably selected from the air (ie, a cover layer is not included during manufacturing, and the air itself of the guide application environment acts as a covering material), silicon dioxide, and a polymer.More preferably, in the case of using a polymer as a covering material, said polymer is selected so that it has a Effective index variation with the sign temperature opposite to the variation of the silicon, that is, when a temperature change is applied, the modification in the effective indices of the SWG structure caused by the cover and the core show opposite signs, thus mitigating the variability of the guide's response to environmental changes.
    [0048]
    [0049] In order to optimize the insertion losses in input and output transitions of the modified birefringence single-mode guide (for example, in an interface with a conventional continuous waveguide, or with a SWG guide without rotation), said waveguides Modified birefringence preferably comprises at least one modal adapter. Modal adapters comprise SWG structures with a variable width and / or a progressive rotation between a direction perpendicular to the waveguide and the angle of rotation of the SWG structure. Also preferably, the modal adapters comprise a central bridge of width inversely proportional to the width of the adapter. For example, if a continuous waveguide with a first width is connected through the modal adapter to a waveguide birefringence modified with a second width, said modal adapter progressively increases its width from said first width to said second width, while the central bridge decreases progressively from said first width to a third width (smaller than the first width), or until disappearing completely at the end of the modal adapter.
    [0050]
    [0051] In a second aspect of the invention, a polarization divider system based on selective directional polarization coupling is constituted, constituted from the modified birefringence single-mode waveguide of the first aspect of the invention. The device comprises two adjacent single-mode guides (which we will call first guide and second guide), so that when a zero-order magnetic transverse mode is introduced by the first guide, an attachment to the second guide is produced; while when a zero-order electrical transverse mode is introduced by the first guide, said coupling to the second guide does not occur.
    [0052]
    [0053] To achieve said polarization selective behavior, at least the second single-mode guide comprises a SWG structure whose interfaces between the plurality of sections of the core material and the plurality of sections of the covering material form an angle greater than zero with a plane perpendicular to a Direction of propagation of guided light. Depending on the particular implementation, the first single-mode guide can be a continuous waveguide, a SWG waveguide with interfaces perpendicular to the direction of propagation, or a rotated SWG waveguide with geometric properties (width, angle of rotation, period and / or filling factor) other than those of the second waveguide.
    [0054]
    [0055] Preferably, the polarization selective behavior can be enhanced by including an auxiliary central structure arranged between the first single-mode waveguide and the second single-mode waveguide. In particular, said auxiliary structure can be a homogeneous segment of core material, a homogeneous segment of a material other than the core material, or a heterogeneous structure that combines multiple materials (for example, a metamaterial or a SWG structure).
    [0056]
    [0057] The birefringence control provided by the waveguide of the first aspect of the invention, when applied in the described directional coupling polarization division system, allows reducing the dimensions of the system, while they optimize the rest of benefits (insertion losses, extinction ratio, bandwidth, etc.).
    [0058]
    [0059] In a third aspect of the invention, a method of manufacturing the modified birefringence waveguide of the first aspect of the invention and, consequently, of the polarization divider system of the second aspect of the invention is presented. The method comprises, given geometric parameters and / or materials of the SWG structure (for example, width, height, duty cycle, period, roofing material, core material), determining an angle of rotation of the SWG structure to obtain the objective relationship between the first effective index for the zero-order electrical transverse mode and a second effective index for the zero-order magnetic transverse mode. Such objective relationship may be, for example, to obtain the same value for the first effective index and the second effective index (independent guides to polarization), or obtain a difference greater than a certain threshold between the value of the first effective index and the value of the second effective index (selective guides to polarization). Note that the geometric and / or material parameters of the SWG structure can be fixed parameters or can be modified iteratively within an optimization process. Note also that both the polarization independent behavior and the polarization selective behavior can be obtained for the same geometric and / or material parameters of the SWG structure, simply by modifying the angle of rotation of the SWG structure. However, the particular values of the angle for said purposes will depend on the particular values of said geometric and / or material parameters of the SWG structure.
    [0060]
    [0061] The calculation of the angle to be introduced in the manufactured SWG structure is carried out by means of numerical computations of the effective indices generated by the SWG structure rotated for said angle. In particular, said numerical computations can be performed by means of an algorithm selected from among the photonic simulation algorithms known in the state of the art, although an approximation of the SWG structure by rotation of a diagonal tensor of a homogeneous anisotropic medium is preferably recommended. , thus reducing the computational load of the method.
    [0062]
    [0063] In particular, the method preferably comprises characterizing the SWG structure rotated by a rotated tensioner (ñ) according to the following expression:
    [0064] 0 Hxz
    [0065] ñyy 0
    [0066]
    [0067]
    [0068] where:
    [0069]
    [0070] ñxx = ^ nxxcos2 (a) n2zsin2 (a),
    [0071]
    [0072] ^ y y ~ n yy>
    [0073]
    [0074]
    [0075] ñxz = V (n2z - n2z) without (a) cos (a),
    [0076]
    [0077] [nxx, nyy, nzz] being components of the diagonal tensioner (n) of a homogeneous anisotropic medium (that is, of the SWG structure without turning).
    [0078]
    [0079] The waveguide, polarization divider and design method described thus provide a compact birefringence control, low losses and high bandwidth, manufactured in a single lithography step. That is, the improvement in performance does not involve any increase in manufacturing complexity. These and other advantages of the invention will be apparent in light of the detailed description thereof.
    [0080]
    [0081] Description of the figures
    [0082]
    [0083] In order to help a better understanding of the characteristics of the invention according to a preferred example of practical realization thereof, and to complement this description, the following figures are attached as an integral part thereof, the character of which is illustrative and non-limiting:
    [0084]
    [0085] Figure 1 schematically shows, in a perspective view, a birefringence waveguides modified by rotation of sub-wavelength structures, in accordance with a preferred embodiment of the invention, illustrating the main geometric parameters of said structure.
    [0086]
    [0087] Figure 2 illustrates, in a top view, a preferred embodiment of the modified birefringence waveguide of the invention, in which the angle of rotation is selected. so that an independent polarization behavior is obtained.
    [0088]
    [0089] Figure 3 shows an integrated polarization splitter based on directional coupling with a modified birefringence waveguide, in accordance with a preferred embodiment of the invention.
    [0090]
    [0091] Figure 4 illustrates the effect of the angle of rotation on the anisotropic properties of a SWG structure.
    [0092]
    [0093] Figure 5 illustrates a graph showing the variation of the first effective index (nTE) for the zero-order electrical transverse mode (TE0) and a second effective index (nTM) for the zero-order magnetic transverse mode (TM0) as a function of angle (a) of rotation of the SWG structure.
    [0094]
    [0095] Preferred Embodiment of the Invention
    [0096]
    [0097] Note that the preferred embodiments of the device (single-mode modified birefringence waveguide) and its associated system (polarization splitter based on said guide) object of the invention is preferably implemented in silicon over insulator (SOI) in order to benefit from the high contrast SOI index. However, particular embodiments could be implemented in other different photonic platforms. That is, all waveguides of the device are preferably made by a silicon core, deposited on an insulating layer such as, for example, silicon dioxide. The cover material may vary for different embodiments of the invention, some of the possibilities being silicon dioxide, polymers or air, without this list limiting the use of other possible options.
    [0098]
    [0099] Also, note that the preferred embodiments of the polarization splitter of the invention are described with the system operating as a polarization splitter. However, the same system can operate reciprocally as a polarization multiplexer, that is, by combining two orthogonal polarization signals from two input guides into the same output guide, simply by reversing the direction of operation of the device.
    [0100]
    [0101] Regarding the manufacturing of the proposed devices, note that the sub-wavelength (SWG) structures, regardless of their angle of rotation with respect to the axis optical, they do not increase the difficulty or the number of steps with respect to the manufacture of conventional waveguides. That is, all the structures used by the polarization splitter of the invention can be manufactured by a single step of full depth exposure of any conventional microelectronic recording technique, such as, for example, by exposure to electron beams ( "e-beam " in English) or deep ultraviolet ( " deep-UV ' in English).
    [0102]
    [0103] Figure 1 schematically shows a preferred embodiment of a waveguide (100), preferably single mode, which allows the adjustment of the birefringence of the light passing through at least part of said waveguide (100) object of a first aspect of the invention, also used in a preferred embodiment of the polarization divider (200) object of a second aspect of the invention, as well as its main geometric parameters.
    [0104]
    [0105] The waveguide (100) is formed by a periodic alternating arrangement of sections of a core material (110) and sections of a covering material (120) with a period (A) less than the wavelength of a propagated light by said periodic arrangement of the waveguide (100); having also arranged between the sections of core material (110) and sections of a covering material (120) interfaces that are rotated an angle (a) with respect to a plane perpendicular to the direction of light propagation (i.e. perpendicular to the main axis of the waveguide). The core material sections (110) of the waveguide (100) have a height (H) and a width (W) and are arranged on a support material (130) that acts as an insulating layer. On this structure, a filling factor or duty cycle (f) is defined as the ratio between the proportion of cover material (a) and the proportion of core material (b) within a period (A). The particular values of all these geometric parameters are defined prior to the manufacture of the device by numerical simulations in accordance with that described by the method of the invention.
    [0106]
    [0107] In particular, the waveguide (100) is preferably modeled as a rotated tensioner (ñ) according to the following expression:
    [0108]
    [0109]
    [0110] where:
    [0111]
    [0112] ñxx = ^ nxxcos2 (a) nlzsin2 (a),
    [0113] ñyy - nyy,
    [0114]
    [0115]
    [0116]
    [0117] ñxz = V (n | z - n2z) without (a) cos (a),
    [0118]
    [0119] [nxx, nyy, nzz] being components of a digital tensor (n) of the equilateral homogeneous isotropic lens to the SW G structure without rotating (ie, interfaces perpendicular to the main axis of the waveguide). This modeling can provide a final value of the angle (a), or serve as an approximation, refined in a second stage of calculation by a complete simulation (ie , without approximations of SW G structures with homogeneous homologues) of the structure.
    [0120]
    [0121] Figure 2 shows a schematic top view of a preferred embodiment of the waveguide (100) of the invention (ie, a view in a plane for the interface between the support (130) and the core (110), and in which therefore the light propagates following the horizontal direction of the figure). Waveguide (100) has a first effective index (nTE) for the zero-order electrical transverse mode (TE0) and a second effective index (nTM) for the zero-order agnhetic lm transverse method (TM 0 ) at each wavelength (A). Depending on the angle (a), for some specific geometric and physical conditions, the first index of the fective index (nTE) can be equal to the second effective index (nTM), it ignites it tivam ent d istin to ad icho second index e fective
    [0122] In order to reduce reflection losses at the waveguide interfaces (100), said waveguide (100) may comprise a modal adapter (140) at each end. Each modal adapter (140) has at least one SWG structure with the same period (A) and duty cycle (f) as the waveguide (100), while its width varies progressively from the width of a waveguide single-mode to a final width of the modal adapter (140), preferably greater than the width of the single-mode waveguide so that, preferably, the SWG structures of the modal adapter (140) have an incremental width. Each modal adapter (140) also comprises a central bridge (141), that is, a small core material connector in the center of the cover material sections (120). The width of the central bridge decreases as the total width of the respective modal adapter (140) increases, completely disappearing at the interface with the SWG structure rotated. Note that the specific geometry of the modal adapter (140) may vary between implementations provided a progressive and smooth modal transition is guaranteed.
    [0123]
    [0124] Figure 3 shows a particular embodiment of a polarization splitter (200) corresponding to a second aspect of the invention and comprises a directional coupler which in turn preferably comprises adjacent first guides (210) and a second single-mode guide (220), said second single-mode guide (220) being a particular embodiment of the waveguide (100) of the first aspect of the invention. In this case, the first single-mode guide (210) is a SWG waveguide with interfaces perpendicular to the axis of the guided light, and with two modal adapters (140) located at its ends, although in other embodiments of the invention, the First single-mode guide (210) can be a continuous wave guide or comprise SWG structures with other alternative geometries.
    [0125]
    [0126] Additionally, the polarization splitter (200) can comprise a central structure (230), arranged between the first single-mode guide (210) and the second single-mode guide (220), which allows to enhance the polarization selective properties of the system and improve its benefits. In this example, the central structure (230) is simply a preferably homogeneous rectangular segment of the same material as the core material sections (110). However, in other particular embodiments, the central structure (230) can be implemented by other geometries and / or alternative materials.
    [0127] During operation as a polarization splitter (200), the modes TE0 and TM0 are introduced in the same input of the first single-mode waveguide (210). While the TM0 mode is coupled to the second single-mode waveguide (220), following the general behavior of any directional coupler, the TE0 mode is confined to the first single-mode waveguide (210) thus obtaining a high polarization division. efficiency in an extremely small size.
    [0128]
    [0129] The manufacturing process of the polarization divider system (200) is preferably carried out by means of a photonic simulation process consisting of two stages. In a first stage, a first approximation of the design is obtained by simulating the SWG structure as a homogeneous and anisotropic material. The anisotropic material used is defined through a dielectric tensioner, obtained by Rytov approximations. By setting these starting parameters, photonic simulations are performed for a sweep of rotation angles (a), modeling the effect of said rotation using the expressions described for the waveguide (100). This first approach allows three-dimensional simulations to be made reducing the time and computational cost of simulation.
    [0130]
    [0131] Once the anisotropic properties are modeled at different angles for the particular geometry and platform under analysis, said modeling is applied to a first optimization by scanning various parameters such as the width of the multimodal zone, the work cycle of the corresponding real SWG structure or the length of the polarization splitter. Said first optimization process is carried out by running sweeps of the mentioned parameters and imposing as objectives the minimization of total insertion losses. As a result of this optimization, an approximation of the initial design parameters (angle, separation between guides, period, work cycle and device length) is obtained.
    [0132]
    [0133] From the design parameters obtained in the first stage, we proceed to the physical modeling of the complete SWG structure (without approximations to a homogeneous medium) that gives us the final design of the polarization divider (200). Although this process can be carried out maintaining the degrees of freedom of all the design parameters, it is recommended to simplify this second optimization process to reduce the computational load of the same, fixing the width of the multimodal zone, the work cycle, and the period (always imposing that said period be outside the Bragg regime, determined by the relationship of proportionality between the period of the SWG structure and the effective wavelength of the light propagated by said structure). This second optimization process is preferably carried out using three - dimensional finite difference methods in the time domain (FDTD, of the English 'Finite difference time domain method) although other techniques may be equally photonic computing applied to the same.
    [0134]
    [0135] Figure 4 shows a variant of the polarization splitter (200) of the invention, in which the waveguide (100) with which the second waveguide (220) is implemented comprises a plurality of central junctions (140) which connect the core material sections (110) of the SWG structure. The plurality of central joints (140), and in particular the selection of their width provides an additional degree of freedom in the design of the polarization splitter (200), increasing the tuning capacity of the first effective index (n TE ) for the mode electrical transverse order zero (TE 0 ) and the second effective index (n TM ) for the magnetic transverse order zero order (TM 0 ).
    [0136]
    [0137] Finally, Figure 5 shows schematically a variation of the first effective index (n TE ) for the zero-order electrical transverse mode (TE 0 ) and a second effective index (n TM ) for the zero-order magnetic transverse mode (TM 0 ) depending on the angle (a) of rotation of the SWG structure. Although the particular dependencies of these indices with the angle (a) vary depending on the materials used and the rest of the geometric properties, it should be noted that the effect of such rotation is greater for the TE 0 mode than for the TM mode 0 , and also its variation has opposite signs. This allows, on the one hand, to alter the properties of the first effective index (n TE ) without hardly modifying the response of the second effective index (n TM ), thus developing selective polarization devices; and on the other hand, to determine an angle for polarization independence (a ind ) in which it is verified that both the first effective index (n TE ) and the second effective index (n TM ) are equal to each other, taking an index value effective independent of polarization (n ind ).
    [0138]
    [0139] In view of this description and figures, the person skilled in the art may understand that the invention has been described according to some preferred embodiments thereof, but that multiple variations can be introduced in said preferred embodiments, without departing from the object of the invention such and as claimed.
    权利要求:
    Claims (24)
    [1]
    1. Waveguide (100) comprising a plurality of sections of a core material (110) and a plurality of sections of a covering material (120) alternately arranged periodically with a period (A) less than the length wave (A) of a light guided through the waveguide (100); the waveguide (100) being characterized in that it is single mode and comprises interfaces defined respectively between each of the sections of the plurality of sections of core material (110) and each of the sections of the plurality of sections of material of coverage (120) forming an angle (a) greater than zero with respect to a plane perpendicular to a direction of propagation of the light intended to be guided by the waveguide (100).
    [2]
    2. Waveguide (100) according to claim 1 characterized in that the angle (a) is selected such that a first effective index (nTE) of a zero-order electrical transverse mode (TE0) is different from a second effective index (nTM) of a zero-order magnetic transverse mode (TM0),).
    [3]
    3. Waveguide (100) according to claim 1 characterized in that the angle (a) is selected such that a first effective index (nTE) of a zero-order electrical transverse mode (TE0) is equal to a second effective index (nTM) of a zero order magnetic transverse mode (TM0).
    [4]
    4. Waveguide (100) according to any of the preceding claims characterized in that it comprises at least one modal adapter (140) connected to an input of the waveguide (100), said at least one modal adapter (140) comprising ) a plurality of sections of core material (110) and sections of cover material (120) arranged alternately and periodically with a period (A) less than the wavelength (A) of a light guided by the at least a modal adapter (140), and the plurality of sections of core material (110) being arranged with progressive angles between a plane perpendicular to the direction of propagation of the guided light and the angle (a).
    [5]
    5. Waveguide (100) according to claim 4 characterized in that the at least one modal adapter (140) comprises a plurality of central bridges (141) of core material that joins the plurality of sections of the core material (110) of said modal adapter (140), the width of each central bridge ( 141) inversely proportional to the width of the modal adapter (140).
    [6]
    6. Waveguide (100) according to any one of claims 4 and 5 characterized in that the sections of the core material (210) of the at least one modal adapter (140) have a variable width.
    [7]
    7. Waveguide (100) according to any one of the preceding claims characterized in that the plurality of sections of core material (110) and the plurality of sections of cover material (120) have constant geometric properties along of the waveguide length (100).
    [8]
    8. Waveguide (100) according to any one of claims 1 to 6 characterized in that the plurality of sections of core material (110) and the plurality of sections of cover material (120) have variable geometric properties to along the length of the waveguide (100).
    [9]
    9. Waveguide (100) according to any one of the preceding claims characterized in that the plurality of sections of core material (110) have at least one internal groove of the covering material.
    [10]
    10. Waveguide (100) according to any one of claims 1 to 8 characterized in that the plurality of sections of core material (110) have a plurality of central junctions (150) of the core material.
    [11]
    11. Waveguide (100) according to any one of the preceding claims characterized in that the material of the core material sections (110) is silicon.
    [12]
    12. Waveguide (100) according to claim 11 characterized in that the material of the cover material sections (120) is silicon dioxide.
    [13]
    13. Waveguide (100) according to claim 11 characterized in that the material of the cover material sections (120) is a polymer with an effective index variation with the signed temperature value opposite to the variation of the Silicon core material sections (110).
    [14]
    14. Waveguide (100) according to claim 13 characterized in that the proportion of cover material with respect to the material of the core material sections (110) within a period (A) is selected so that it is minimized a variation with the temperature of the first effective index (nTE) and the second effective index (nTM).
    [15]
    15. Polarization splitter (200), comprising a first waveguide (210) and a second adjacent waveguide (220) arranged at a distance (d), characterized in that at least the second waveguide (220) it is a waveguide (100) according to any one of claims 1 to 14.
    [16]
    16. Polarization splitter (200) according to claim 15 characterized in that the first waveguide (210) is a continuous waveguide.
    [17]
    17. Polarization splitter (200) according to claim 15 characterized in that the first waveguide (210) is a waveguide with a plurality of sections of a core material (110) and a plurality of sections of a cover material (120) alternately arranged periodically with a period (A) less than the wavelength (A) of the guided light.
    [18]
    18. Polarization splitter (200) according to any one of claims 15 to 17 characterized in that it further comprises a central structure (230) disposed between the first waveguide (210) and the second waveguide (220).
    [19]
    19. Polarization splitter (200) according to claim 18 characterized in that the central structure (230) is a homogeneous segment of core material.
    [20]
    20. Polarization splitter (200) according to claim 18 characterized because the central structure (230) is a homogeneous segment of a material other than the core material.
    [21]
    21. Polarization divider (200) according to claim 18 characterized in that the central structure (230) is a heterogeneous structure that combines multiple materials.
    [22]
    22. Method of manufacturing the waveguide (100) described in any one of claims 1 to 14 characterized in that it comprises, given a core material and a waveguide covering material (100), providing a plurality of sections of core material (110) and a plurality of sections of cover material (120) defining between each of the sections of core material (110) and each of the sections of cover material (120) interfaces which respectively form an angle (a) greater than zero with respect to a plane perpendicular to a direction of propagation of the light intended to be guided by the waveguide (100).
    [23]
    23. Method according to claim 22, characterized in that the angle (a) is determined by approximation of the waveguide (100) using a rotated tensioner (ñ), resulting from rotating a diagonal tensioner (n) of a Homogeneous half anisotropic.
    [24]
    24. Method according to claim 23, characterized in that it comprises calculating the rotated tensioner (ñ) according to:

    with:
    ñ x x = lnxxcos2 O) n ^ sin2 (a),
    n y y n yy>
    ñzz = J: n2xxsin2 (a ) n2zcos2 (a),
    ñxz = J (n 2z - n% z) without (a) cos (a),
    [nxx, nyy, nzz] being components of the diagonal tensor (n) of the homogeneous anisotropic medium.
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    同族专利:
    公开号 | 公开日
    WO2020002739A4|2020-03-26|
    WO2020002739A1|2020-01-02|
    ES2736899B2|2020-05-11|
    EP3816687A1|2021-05-05|
    SG11202013094UA|2021-01-28|
    US20210263210A1|2021-08-26|
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    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US5090790A|1990-06-29|1992-02-25|At&T Bell Laboratories|Polarization-independent semiconductor waveguide|
    JP3142081B2|1992-04-13|2001-03-07|日本電信電話株式会社|Waveguide type optical branching device|
    US5838842A|1997-01-10|1998-11-17|The United States Of America As Represented By The Secretary Of The Army|Self-imaging waveguide optical polarization or wavelength splitters|
    US6795597B2|2002-03-15|2004-09-21|Optimer Photonics, Inc.|Electrode and core arrangements for polarization-independent waveguides|
    ES2379058B2|2012-02-23|2012-10-01|Universidad De Málaga|Waveguide coupler device, and design method of said device|
    CN106959485A|2017-04-28|2017-07-18|中国人民解放军国防科学技术大学|The directional coupled TM polarizers and beam splitter based on sub-wave length grating|
    ES2722753A1|2018-02-13|2019-08-16|Consejo Superior Investigacion|INTEGRATED POLARIZATION DIVIDER |
    法律状态:
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    ES201830653A|ES2736899B2|2018-06-29|2018-06-29|WAVE GUIDE, METHOD OF MANUFACTURE OF SUCH WAVE GUIDE AND POLARIZATION DIVIDER THAT MAKES USE OF SUCH WAVE GUIDE|ES201830653A| ES2736899B2|2018-06-29|2018-06-29|WAVE GUIDE, METHOD OF MANUFACTURE OF SUCH WAVE GUIDE AND POLARIZATION DIVIDER THAT MAKES USE OF SUCH WAVE GUIDE|
    SG11202013094UA| SG11202013094UA|2018-06-29|2019-06-27|Waveguide, waveguide production method, and polarisation splitter using said waveguide|
    US17/255,937| US20210263210A1|2018-06-29|2019-06-27|Waveguide, manufacturing method of said waveguide and polarisation splitter which makes use of said waveguide|
    PCT/ES2019/070452| WO2020002739A1|2018-06-29|2019-06-27|Waveguide, waveguide production method, and polarisation splitter using said waveguide|
    EP19759632.3A| EP3816687A1|2018-06-29|2019-06-27|Waveguide, waveguide production method, and polarisation splitter using said waveguide|
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