CN103885136B - light modulator - Google Patents

Abstract

A kind of light modulator, including：Substrate, with relative first surface and second surface；Planar optical waveguide, is used to be docked with a light source to receive the light beam that the light source sends, the area of the area less than the second surface of the planar optical waveguide positioned at the second surface；Grating, is formed in the planar optical waveguide, and the grating sets along the incident direction of the parallel light beam and constitutes an optical waveguide lens with the planar optical waveguide；And a pair of electrodes, on the second surface and positioned at the both sides of the planar optical waveguide, the electrode is used for the focal length for forming a modulation electric field to change the refractive index of the planar optical waveguide by electrooptic effect so as to change the optical waveguide lens.

Description

Light modulator

Technical field

The present invention relates to a kind of light modulator.

Background technology

In integrated optics, the problem that light source considers with the coupling needs of light path has：Although integrated optics is generally using side Tropism preferably laser is used as light source, but the light beam that laser sends still has certain angle of divergence, if directly allow light source and Light path is docked, and the divergent rays in light beam will be unable to enter light path, and light utilization efficiency is low.Therefore, how by light source couples to light path So that it is an important topic that the light beam of diverging is assembled into light path to improve light utilization efficiency.

The content of the invention

In view of this, it is necessary to which providing one kind can improve the light modulator of light utilization efficiency.

A kind of light modulator, including：Substrate, with relative first surface and second surface；Planar optical waveguide, positioned at institute Second surface is stated for being docked with a light source to receive the light beam that the light source sends, the area of the planar optical waveguide is less than institute State the area of second surface；Grating, is formed in the planar optical waveguide, the grating along the parallel light beam incident direction Set and constitute an optical waveguide lens with the planar optical waveguide；And a pair of electrodes, on the second surface and it is located at The both sides of the planar optical waveguide, the electrode changes the plane light wave for forming a modulation electric field with by electrooptic effect The refractive index led is so as to change the focal length of the optical waveguide lens.

Compared to prior art, the light modulator of the present embodiment has the fiber waveguide of planar optical waveguide and optical grating constitution saturating Mirror, forms a modulation electric field between electrode, the modulation electric field can change the refractive index of planar optical waveguide, so as to change on one's own initiative Become the focal length of optical waveguide lens, light collection is entered into other optical modules, so as to lift the coupling efficiency of light and improve light utilization Rate.

Brief description of the drawings

Fig. 1 is the schematic perspective view of embodiment of the present invention light modulator.

Fig. 2 is the Electric Field Distribution schematic diagram of embodiment of the present invention light modulator.

Main element symbol description

Light modulator	10
		Substrate	11
First surface	111
		Second surface	112
Side	113
		Electrode	12
Planar optical waveguide	13
		Grating	14
Raised part	141
		Space	142
Light source	20
		Light receiving unit	30

Following specific embodiment will further illustrate the present invention with reference to above-mentioned accompanying drawing.

Specific embodiment

Refer to Fig. 1 and Fig. 2, the light modulator 10 of embodiment of the present invention offer is used for light beam that modulation light source 20 sends simultaneously Light beam convergence after modulation is exported to light receiving unit 30.

Light receiving unit 30 can be optical splitter（Splitter）, fiber waveguide（Waveguide）Or optical fiber etc.（Fiber）.

Light modulator 10 includes substrate 11, a pair of electrodes 12, planar optical waveguide 13 and grating 14.

Substrate 11 is substantially rectangular, and with relative first surface 111, second surface 112 and with first surface 111 The side 113 being connected with second surface 112.Substrate 11 is made up of the crystalline material with electrooptic effect, for example lithium niobate（）Crystal.

Planar optical waveguide 13 can plate Titanium by the second surface 112 of substrate 11（Ti）High temperature is by Titanium afterwards Diffuse into substrate 11 and formed.The shape of corresponding substrate 11, planar optical waveguide 13 is that rectangle and planar optical waveguide 13 are located at the The zone line on two surfaces 112, second surface 112 is the top surface of planar optical waveguide 13, and side 113 is planar optical waveguide 13 Side.

After the diffusion Titanium of substrate 11, part of the two ends of substrate 11 containing Titanium is removed, so that planar optical waveguide 13 Occupy the area of the area less than second surface 112 of second surface 112.

A pair of electrodes 12 is arranged on the second surface 112 of substrate 11 and positioned at the both sides of planar optical waveguide 13, electrode 12 Height be not higher than the height of planar optical waveguide 13.The material of electrode 12 can be aluminium, and can be by plated film mode（Example Such as, PVD modes）It is formed on second surface 112.

Grating 14 is by the top surface from planar optical waveguide 13（That is second surface 112）Etching planar optical waveguide 13 is formed（Example Such as, using hydrofluoric acid etch planar optical waveguide 13 so as in formation grating 14 in planar optical waveguide 13）, therefore, the material of grating 14 Also it is the lithium columbate crystal for being diffused with Titanium, in other words, the material of grating 14 is identical with the material of planar optical waveguide 13.

Grating 14 includes odd number and the raised part 141 be arrangeding in parallel and the space between raised part 141 142,141 vertical second surfaces 112 of raised part are set, and highly essentially identical.Raised part 141 is on a symmetry axis O It is symmetrical, and along symmetry axis O to the direction away from symmetry axis O, the width of raised part 141 is less and less and two neighboring convex The space 142 risen between part 141 is also less and less.

The incident direction of the light beam that grating 14 sends along source of parallel light 20 sets and constitutes a ridge with planar optical waveguide 13 Raster pattern optical waveguide lens.From the manufacturing process of grating 14, the material of grating 14 is identical with the material of planar optical waveguide 13, The section of grating 14 can be rectangle, square or trapezoidal etc..

In other embodiment, the material of grating 14 can be different from the material of planar optical waveguide 13, the material of grating 14 Material can be the material with high index of refraction, refractive index of the refractive index more than or equal to planar optical waveguide 13.

Light source 20 uses distributed feedback laser（Distributed Feedback Laser, DFB）, it belongs to side Luminous laser, can weld by chip（Die Bond）Be welded direct on side 113 for luminous side by mode, with Make the light beam for sending incident along symmetry axis O.

Certainly, light source 20 can also use other types of light source, and be set by other manner, as long as ensureing that it can edge Symmetry axis O outgoing beams.

When a demodulating voltage is applied on electrode 12, an electric field for modulation can be produced between electrode 12, modulation Electric field, such that it is able to further change the equivalent refractive index of planar optical waveguide 13, will equally change through planar optical waveguide 13 Become the refractive power of the optical waveguide lens that planar optical waveguide 13 is constituted with grating 14（That is focal length）, such that it is able to coupling light source 20 and Light receiving unit 30, lifts the coupling efficiency of light and improves light utilization efficiency.

Both sides and planar optical waveguide 13 and 12, the electrode of planar optical waveguide 13 are located at due to the electrode 12 of light modulator 10 In in approximately the same plane so that electric field level distribution in planar optical waveguide 13 with and the substantially parallel substrate of direction of an electric field 11。

It is understood that those skilled in the art can also do other changes etc. used in of the invention in spirit of the invention Design, without departing from technique effect of the invention.These changes done according to present invention spirit, should all be included in Within scope of the present invention.

Claims (7)

1. a kind of light modulator, including：

Substrate, with relative first surface and second surface；

Planar optical waveguide, is used to be docked with a light source to receive the light beam that the light source sends positioned at the second surface, described Area of the area of planar optical waveguide less than the second surface；

Grating, is formed in the planar optical waveguide, the grating along the parallel light beam incident direction set and with it is described Planar optical waveguide constitutes an optical waveguide lens；And,

A pair of electrodes, on the second surface and positioned at the both sides of the planar optical waveguide, the electrode is used for forming one Focal length of the modulation electric field to change the refractive index of the planar optical waveguide by electrooptic effect so as to change the optical waveguide lens.

2. light modulator as claimed in claim 1, it is characterised in that the height of the electrode is not higher than the planar optical waveguide Height.

3. light modulator as claimed in claim 1, it is characterised in that the material lithium columbate crystal of the substrate.

4. light modulator as claimed in claim 1, it is characterised in that the section of the grating is rectangle or square.

5. light modulator as claimed in claim 1, it is characterised in that the planar optical waveguide on the substrate by spreading Titanium and formed.

6. light modulator as claimed in claim 5, it is characterised in that the grating is by etching the planar optical waveguide Into.

7. light modulator as claimed in claim 1, it is characterised in that the material of the electrode is aluminium.