CN103869412A - Optical coupling device - Google Patents

Abstract

The invention provides an optical coupling device. The optical coupling device comprises a substrate, a planar optical waveguide formed on the substrate, a dielectric grating formed on the planar optical waveguide, and a pair of electrodes which are arranged on the planar optical waveguide and are positioned on the two sides of the dielectric grating. The planar optical waveguide is used for butting a laser source so as to receive the laser beams emitted from the laser source. The dielectric grating is arranged along the incidence direction parallel to the laser beams and forms a diffractive optical waveguide lens with the planar optical waveguide lens to converge the laser beams. The pair of electrodes is used for loading a modulation electric field, so that the focal distance of the diffractive optical waveguide lens is changed by changing the refraction index of the planar optical waveguide changed through an electro-optical effect. Therefore, the laser beams can be converged into an optical element effectively.

Description

Optically coupled device

Technical field

The present invention relates to integrated optical device, particularly a kind of optically coupled device.

Background technology

In integrated optics, the problem that the coupling of light source and optical element need to be considered has: although integrated optics generally adopt directivity preferably laser as light source, but the light beam that laser sends still has certain angle of divergence, if directly allow light source dock with optical element, divergent rays in light beam cannot enter optical element, and light utilization efficiency is low.Therefore, how light source is coupled to optical element so that the light beam of dispersing assemble into optical element with improve light utilization efficiency be an important topic.

Summary of the invention

In view of this, be necessary to provide a kind of optically coupled device that improves light utilization efficiency.

A kind of optically coupled device, it comprises that a substrate, one are formed at this suprabasil planar light waveguide, dielectric grating and an a pair of electrode that is arranged on this planar light waveguide and is positioned at these dielectric grating both sides being formed on this planar light waveguide.This planar light waveguide is for docking to receive with a LASER Light Source laser beam that this LASER Light Source is sent.This dielectric grating edge is parallel to the incident direction setting of this laser beam, and forms diffraction type optical waveguide lens (diffractive waveguide lens) to assemble this laser beam with this planar light waveguide.Thereby this changes the focal length of this diffraction type optical waveguide lens to change the refractive index of this planar light waveguide by electrooptical effect for load-modulate electric field to electrode.

According to integrated optics theory, this dielectric grating and this planar light waveguide form loaded type optical waveguide (strip/grating loaded waveguide), and the equivalent refractive index that this planar light waveguide loads the part of this dielectric grating becomes large.So, by the structure of this dielectric grating is rationally set, for example, be arranged to chirp grating (chirped grating) and just can form the diffraction type optical waveguide lens of a chirp grating type.Thereby and this can change the refractive index of this planar light waveguide by load-modulate electric field to electrode by electrooptical effect, thereby change the focal length of this diffraction type optical waveguide lens, effectively this laser beam is assembled into optical element.

Brief description of the drawings

Fig. 1 is the schematic perspective view of the optically coupled device of preferred embodiments of the present invention.

Fig. 2 is the diagrammatic cross-section of the optically coupled device II-II along the line of Fig. 1.

Fig. 3 is the floor map of the dielectric grating of the optical coupling device of Fig. 1.

Main element symbol description

Optically coupleddevice	10
		Substrate	110
End face	111
		Side	112
Planar light waveguide	120
		Dielectric grating	130
Medium part	131
		Electrode	140
Axis of symmetry	O
		LASER Light Source	20
Laser beam	21
		Optical element	30

Following embodiment further illustrates the present invention in connection with above-mentioned accompanying drawing.

Embodiment

Refer to Fig. 1 and Fig. 2, the optically coupleddevice 10 of preferred embodiments of the present invention comprises that asubstrate 110, one are formed at planar light waveguide in thissubstrate 110 120, one and are formed atdielectric grating 130 and a pair ofelectrode 140 that is arranged on thisplanar light waveguide 120 and is set in parallel in thesedielectric grating 130 both sides on this planar light waveguide 120.Thisplanar light waveguide 120 is for docking to receive thelaser beam 21 that this LASER Light Source 20 is sent with a LASER Light Source 20.Thesedielectric grating 130 edges are parallel to the incident direction setting of thislaser beam 21, and form a diffraction type optical waveguide lens to assemble thislaser beam 21 with this planar light waveguide 120.Thereby this changes the focal length of this diffraction type optical waveguide lens to change the refractive index of thisplanar light waveguide 120 by electrooptical effect for load-modulate electric field toelectrode 140.

According to integrated optics theory, thisdielectric grating 130 forms loaded type optical waveguide with thisplanar light waveguide 120, and the equivalent refractive index that this planar light waveguide 120 loads the part of thisdielectric grating 130 becomes large.So, by the structure of thisdielectric grating 130 is rationally set, for example, be arranged to chirp grating and just can form the diffraction type optical waveguide lens of a chirp grating type.Thereby and this can change the refractive index of thisplanar light waveguide 120 by load-modulate electric field toelectrode 140 by electrooptical effect, thereby change the focal length of this diffraction type optical waveguide lens, effectively thislaser beam 21 is assembled into anoptical element 30.

Thissubstrate 110 is substantially rectangular, and comprises anend face 111 and aside 112 being connected with this end face 111.Due to lithium niobate (LiNbO₃) crystal (LN) has higher reaction velocity, and consider that lithium niobate diffuse metal titanium (simple substance) can form the loaded lightguide of gradually changed refractive index type, therefore, the material of thissubstrate 110 adopts lithium columbate crystal.

Thisplanar light waveguide 120 diffuses into thissubstrate 110 by Titanium and forms by plate after Titanium high temperature to this end face 111.So, loading after thisdielectric grating 130, the refractive index generation gradual change of thisplanar light waveguide 120, is the advantage that produces the diffraction type optical waveguide lens of chirp grating type.In the present embodiment, to shape that should substrate 110, thisplanar light waveguide 120 is rectangle, and thisend face 111 is the end face of thisplanar light waveguide 120, and thisside 112 is the side of thisplanar light waveguide 120.

Thisdielectric grating 130 forms by the end face from this planar light waveguide 120 (i.e. this end face 111) thisplanar light waveguide 120 of etching, and therefore material also has the lithium columbate crystal of Titanium for diffusion.Thisdielectric grating 130 can be a chirp grating.Concrete, thisdielectric grating 130 comprisesmedium part 131 multiple rectangles, that be arranged in parallel, the plurality ofmedium part 131 arranges perpendicular to thisside 112, and highly basic identical.The number of the plurality ofmedium part 131 is odd number, and symmetrical about an axis of symmetry O, and along this axis of symmetry O to the direction away from this axis of symmetry O, the width of thismedium part 131 is more and more less, and the gap of adjacent two thesemedium parts 131 is also more and more less.

Refer to Fig. 3, in present embodiment, taking the Width of thisdielectric grating 130 asaxle, this axis of symmetry O with

the joining of axle is initial point, along this axis of symmetry O to away from the direction of this axis of symmetry O being

axle forward, exists with thislaser beam 21

place with the phase differential at initial point place is

axle, can obtain according to planar light waveguide wave theory:

, wherein

.Of thismedium part 131

individual border

meet following condition:, wherein,

for positive integer,

(for forming this diffraction type optical waveguide lens),

and

for constant relevant to the focal length of this diffraction type optical waveguide lens.So, can be derived from:

.And

situation, the border of thismedium part 131 on this axis of symmetry O left side can obtain by symmetry.

The interpolar electric field that this produces after load-modulateelectric field electrode 140

to cross thisplanar light waveguide 120, thereby can further change the equivalent refractive index of thisplanar light waveguide 120, change equivalently the refractive power (being focal length) of the diffraction type optical waveguide lens of chirp grating type, thereby can be coupled this LASERLight Source 10 and thisoptical element 30 that arrange with various distances.This length toelectrode 140 and be greater than or equal to highly respectively length and the height of thisdielectric grating 130, this length toelectrode 140 and highly equal this by the length of thisdielectric grating 130 and height in present embodiment.

This LASER Light Source 20 adopts distributed feedback laser (distributed feedback laser, DFB), it belongs to the semiconductor laser of side-emitted, can luminous side be welded direct on thisside 112 by chips welding (die bond) mode, so that thislaser beam 21 is along this axis of symmetry O incident.Certainly, this LASER Light Source 20 also can adopt other types LASER Light Source, and arranges by other means, as long as ensure that it can be along thislaser beam 21 of this axis of symmetry O outgoing.

Thisoptical element 30 can be strip optical waveguide, optical fiber or optical splitter (splitter).In present embodiment, thisoptical element 30 is strip optical waveguide.

In a word; those skilled in the art will be appreciated that; above embodiment is only for the present invention is described; and be not used as limitation of the invention; as long as within connotation scope of the present invention, within the appropriate change that above embodiment is done and variation all drop on the scope of protection of present invention.

Claims (7)

Translated fromChinese

1.一种光耦合装置，其包括一个基底、一个形成于该基底上的平板光波导、一个形成于该平板光波导上的介质光栅及一对设置于该平板光波导上且位于该介质光栅两侧的电极；该平板光波导用于与一个激光光源对接以接收该激光光源发出的激光束；该介质光栅沿平行于该激光束的入射方向设置，并与该平板光波导构成一个衍射型光波导透镜以会聚该激光束；该对电极用于加载调制电场以通过电光效应改变该平板光波导的折射率从而改变该衍射型光波导透镜的焦距。1. An optical coupling device comprising a substrate, a slab optical waveguide formed on the substrate, a dielectric grating formed on the slab optical waveguide and a pair of dielectric gratings arranged on the slab optical waveguide and positioned at the dielectric grating Electrodes on both sides; the flat optical waveguide is used for docking with a laser light source to receive the laser beam emitted by the laser light source; the dielectric grating is arranged parallel to the incident direction of the laser beam, and forms a diffraction pattern with the flat optical waveguide The optical waveguide lens is used to converge the laser beam; the pair of electrodes is used to load a modulation electric field to change the refractive index of the flat optical waveguide through the electro-optical effect, thereby changing the focal length of the diffractive optical waveguide lens.2.如权利要求1所述的光耦合装置，其特征在于，该基底的材料采用铌酸锂晶体。2. The optical coupling device according to claim 1, wherein the material of the substrate is lithium niobate crystal.3.如权利要求1所述的光耦合装置，其特征在于，该基底基本呈矩形，并包括一个顶面及一个与该顶面连接的侧面，该平板光波导通过向该顶面镀上金属钛后高温将金属钛扩散入该基底而形成；该平板光波导为矩形，该顶面即为该平板光波导的顶面，该侧面为该平板光波导的侧面。3. The optical coupling device according to claim 1, wherein the base is substantially rectangular, and includes a top surface and a side connected to the top surface, and the planar optical waveguide is coated with metal on the top surface. Titanium is formed by diffusing metal titanium into the substrate at high temperature; the flat optical waveguide is rectangular, the top surface is the top surface of the flat optical waveguide, and the side is the side surface of the flat optical waveguide.4.如权利要求3所述的光耦合装置，其特征在于，该介质光栅通过从该平板光波导的顶面蚀刻该平板光波导而形成。4. The optical coupling device of claim 3, wherein the dielectric grating is formed by etching the slab optical waveguide from the top surface of the slab optical waveguide.5.如权利要求3所述的光耦合装置，其特征在于，该介质光栅是一个啁啾光栅，其包括多个矩形的、平行设置的介质部分，该多个介质部分垂直于该侧面设置，且高度基本相同；该多个介质部分的数目为奇数，并关于一个对称轴对称分布，且沿该对称轴到远离该对称轴的方向，该介质部分的宽度越来越小，而相邻两个该介质部分的间隙也越来越小。5. The optical coupling device as claimed in claim 3, wherein the dielectric grating is a chirped grating comprising a plurality of rectangular, parallel dielectric sections, the plurality of dielectric sections are arranged perpendicular to the side surface, And the height is basically the same; the number of the plurality of media parts is an odd number, and they are distributed symmetrically about a symmetry axis, and along the symmetry axis to the direction away from the symmetry axis, the width of the media part is getting smaller and smaller, while two adjacent The gap between each part of the medium is getting smaller and smaller.6.如权利要求5所述的光耦合装置，其特征在于，以该介质光栅的宽度方向为                                               

轴，该对称轴与

轴的相交点为原点，沿该对称轴到远离该对称轴的方向为

轴正向，该介质部分的第

个边界

满足如下条件：

，其中，

，为正整数，

及

为常数且与该衍射型光波导透镜的焦距相关。6. The optical coupling device according to claim 5, characterized in that, the width direction of the dielectric grating is

axis, the axis of symmetry and

The intersection point of the axes is the origin, and the direction along the axis of symmetry to away from the axis of symmetry is

positive axis, the first part of the medium

boundaries

Meet the following conditions:

,in,

, is a positive integer,

and

is a constant and is related to the focal length of the diffractive optical waveguide lens.7.如权利要求1所述的光耦合装置，其特征在于，该对电极的长度及高度分别大于或者等于该介质光栅的长度及高度。7. The optical coupling device according to claim 1, wherein the length and height of the pair of electrodes are respectively greater than or equal to the length and height of the dielectric grating.

Images