CN202502263U

CN202502263U - Planar optical waveguide structure

Info

Publication number: CN202502263U
Application number: CN201120550242XU
Authority: CN
Inventors: 宋齐望; 孙麦可
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-12-23
Filing date: 2011-12-23
Publication date: 2012-10-24
Anticipated expiration: 2021-12-23

Abstract

The utility model discloses a planar optical waveguide structure, comprising a tapered section waveguide and a constant diameter section waveguide. The tapered section waveguide is connected with a waveguide device, waveguide cores of the tapered section waveguide have a tapered cross section, the width gradually decreases along the direction from an optical fiber to the waveguide device, the tapered section waveguide is composed of N waveguide cores, of which the length gradually increases along the direction from the optical fiber to an optical waveguide, the length of the gap between the waveguide cores gradually decreases, and the waveguide cores are surrounded by cladding materials. The constant diameter section waveguide is connected with the optical fiber and is composed of M waveguide cores of the same length, the length of the gap between the waveguide cores are the same, and the waveguide cores are surrounded by cladding materials. The mode field distribution of light beams in the optical waveguide can be changed by changing the shape and the size of sections in the width and length directions of the waveguide cores, coupling loss between the optical waveguide and the optical fiber is effectively reduced, and product performance is improved. Besides, the waveguide structure has the advantages of relatively simple manufacture and easy mass production.

Description

Planar Optical Waveguide Structures

Technical field

The utility model relates to the optical waveguide field, particularly, relates to a kind of Planar Optical Waveguide Structures.

Background technology

Since AT&T Labs in 1969 proposes the integrated notion of light so far first; Through years of development, the light integrated technology has been obtained significant progress, particularly over past ten years; Optical communication develops to two-forty, jumbo direction, and is also more and more urgent for the demand of optical integrated device.

The plane light wave waveguide technology is as the integrated core technology of light, and its device volume of producing is little, integrated level is high, good reliability.Most of integrated optical device like photomodulator, photoswitch, luminous-power distributor, photo-coupler, wavelength division multiplexer, optical filter, polarization beam apparatus, lenticule or the like, all is the waveguide devices that is the basis with the plane light wave waveguide technology.For these planar optical waveguide devices are applied to optical communication system, then must consider how planar optical waveguide device and optical fiber are coupled effectively, and the height of coupling efficiency directly has influence on the performance of various optical integrated devices.

A desirable coupling should be that efficient is high, can obtain big as far as possible fiber power, is beneficial to the transmission range and the signal to noise ratio (S/N ratio) that improves system of expanding system; Also to accomplish to reflect little, can reduce of the influence of coupled reflection light as far as possible the integrated optical device operating characteristic.If between optical fiber and the waveguide is desirable aiming at, the total insertion loss of coupling just comprises the mould field mismatch loss between Fresnel reflection (both ends of the surface repeatedly reflect) loss, loss and optical fiber and waveguide.Fresnel reflection loss generally can be subdued through using index-matching fluid or plating one deck anti-reflecting layer at Waveguide end face.In total insertion loss, the mismatch loss of mould field is a principal element, because the transfer of luminous energy is to accomplish through the coupling of mould field in wave guide mode field and the optical fiber in waveguide and the optical fiber.

As everyone knows; The mould field is Gaussian distribution in the single-mode fiber; And optical fiber is the circle symmetry, and in general integrated optical device, optical waveguide generally is a rectangle; And under exhausted most situation the distribution of refractive index also the index distribution with optical fiber is different, so its mould field distribution size with all can not be complementary in shape with the mould field in the optical fiber.Particularly when the fiber waveguide device size is reduced, (δ n=(n1-n2)/n1) will increase the refringence δ n of its optical waveguide sandwich layer refractive index n 1 and cladding index n2, to such an extent as to penetrate rate variance much larger than the core/packing of universal optical fibre, cause mould field mismatch.Therefore, must manage to change optical waveguide or the cross sectional shape of optical fiber and size, change the mould field distribution in optical waveguide and the optical fiber, thereby improve the coupling efficiency between optical waveguide and optical fiber.

Along with optical communication develops to two-forty, high capacity, long range direction, people require also increasingly high to the coupling of various integrated optical devices and optical fiber.For this reason, people begin to attempt changing optical waveguide structure, develop various " mode converters ".

In sum, in the process that realizes the utility model, utility model people finds to exist at least in the prior art following defective: existing Planar Optical Waveguide Structures coupling loss is high.

The utility model content

The purpose of the utility model is, to the problems referred to above, proposes a kind of Planar Optical Waveguide Structures, to realize that coupling loss is low and it is simple to make, advantage that be easy to large-scale production.

For realizing above-mentioned purpose, the technical scheme that the utility model adopts is:

A kind of Planar Optical Waveguide Structures comprises conical section waveguide and the section waveguide of permanent footpath, and said conical section waveguide links to each other with waveguide device; Its waveguide core xsect is taper, and width reduces to the wave guide direction along optical fiber gradually, is made up of N waveguide core; And along optical fiber to the optical waveguide direction; Waveguide core length increases gradually, and the gap length between each waveguide core reduces gradually, is full of clad material around the waveguide core;

Said permanent footpath section waveguide links to each other with optical fiber, is made up of M the waveguide core with equal length, and the gap length between each waveguide core is identical, all is full of clad material around the waveguide core.

According to the preferred embodiment of the utility model, said N is at least 3, and said M is 4-15.

The technical scheme of the utility model is through changing cross sectional shape and the size of waveguide core at width and length direction; Change the mould field distribution of light beam in the waveguide whereby; Reduced the coupling loss between waveguide and optical fiber effectively, improved properties of product, in addition; This waveguiding structure is manufactured simple relatively, is easy to large-scale production.

Through accompanying drawing and embodiment, the technical scheme of the utility model is done further detailed description below.

Description of drawings

Accompanying drawing is used to provide the further understanding to the utility model, and constitutes the part of instructions, is used to explain the utility model with the embodiment of the utility model, does not constitute the restriction to the utility model.In the accompanying drawings:

Fig. 1 is the structural representation of the described Planar Optical Waveguide Structures of the utility model embodiment;

Fig. 2 a is the structural representation after growth under-clad layer and the waveguide core layer in the described Planar Optical Waveguide Structures method for making of the utility model embodiment;

Fig. 2 b is the structural representation behind the formation photoresist in the described Planar Optical Waveguide Structures method for making of the utility model embodiment;

Fig. 2 c is the structural representation that erodes in the described Planar Optical Waveguide Structures method for making of the utility model embodiment after the unnecessary waveguide core layer;

Fig. 2 d is the structural representation of removing in the described Planar Optical Waveguide Structures method for making of the utility model embodiment behind the unnecessary photoresist;

Fig. 2 e is the structural representation behind the formation top covering in the described Planar Optical Waveguide Structures method for making of the utility model embodiment;

Fig. 3 is the change curve of the coupling loss of optical fiber and optical waveguide with waveguide core gap length difference;

Fig. 4 is the change curve of the coupling loss of optical fiber and optical waveguide with waveguide core width difference.

In conjunction with accompanying drawing, Reference numeral is following among the utility model embodiment:

The waveguide of 1-conical section; The section waveguide of the permanent footpath of 2-; The 3-waveguide core; The 4-substrate; The 5-under-clad layer; The 6-waveguide core layer; The 7-photoresist; The 8-top covering;

The direction of arrow is the optical waveguide direction among the figure.

Embodiment

Describe below in conjunction with the preferred embodiment of accompanying drawing, should be appreciated that preferred embodiment described herein only is used for explanation and explains the utility model, and be not used in qualification the utility model the utility model.

Embodiment one:

As shown in Figure 1, a kind of Planar Optical Waveguide Structures comprises conical section waveguide 1 and the section waveguide 2 of permanent footpath; Conical section waveguide 1 links to each other with waveguide device, and its waveguide core xsect is taper, and width reduces to the wave guide direction along optical fiber gradually; Form by 3 waveguide core 3, and along optical fiber to the optical waveguide direction, waveguide core 3 length increase gradually; Gap length between each waveguide core reduces gradually, is full of clad material around the waveguide core;

The section waveguide 2 of permanent footpath links to each other with optical fiber, is made up of 4 waveguide core 3 with equal length, and the gap length between each waveguide core is identical, all is full of clad material around the waveguide core.

Wherein the waveguide core in the conical section waveguide is selected 3 at least for use, and the waveguide core in the section waveguide of permanent footpath can be selected 7,9,13 or 15 for use, and it selects for use number to be generally 4 to 15.

Embodiment two:

Shown in Fig. 2 a to Fig. 2 e, a kind of method for making of Planar Optical Waveguide Structures,

Select for use silicon dioxide or silicon as substrate 4, growth under-clad layer and waveguide core layer 6 are doped with silicon dioxide in this waveguide core layer on substrate 4, make the waveguide core layer refractive index a little more than substrate;

On above-mentioned waveguide core layer, use the method for photoetching to form photoresist 7 with certain waveguiding structure;

Unnecessary doping waveguide core layer 6 is eroded;

Unnecessary photoresist 7 is removed;

On under-clad layer 5, form the refractive index top covering 8 identical that one deck can cover waveguide core fully with under-clad layer.

Concrete manufacture craft process flow diagram is shown in Fig. 2 a to Fig. 2 e: select for use silicon dioxide or silicon as substrate, and growth under-clad layer and waveguide core layer on substrate, doped silica in the waveguide core layer makes its refractive index a little more than substrate; Photoetching forms the photoresist with certain waveguiding structure on waveguide core layer; Unnecessary doping waveguide core layer is eroded, stay have definite shape part as waveguide core layer; Unnecessary photoresist is removed; On under-clad layer, form the top covering that one deck can cover waveguide core fully, its refractive index is identical with under-clad layer.

This waveguiding structure is complementary its mould field distribution with optical fiber through changing the mould field distribution of planar optical waveguide, improves the coupling loss between optical waveguide and optical fiber thus, realizes that the low-loss of planar optical waveguide and optical fiber is coupled.

Can know δ n for each given optical waveguide=(n1-n2)/n1 through Fig. 3 and Fig. 4, adjustment waveguide core gap length difference and waveguide core width difference can reduce coupling loss.

What should explain at last is: the above is merely the preferred embodiment of the utility model; Be not limited to the utility model; Although the utility model has been carried out detailed explanation with reference to previous embodiment; For a person skilled in the art, it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, and perhaps part technical characterictic wherein is equal to replacement.All within the spirit and principle of the utility model, any modification of being done, be equal to replacement, improvement etc., all should be included within the protection domain of the utility model.

Claims

1. a Planar Optical Waveguide Structures is characterized in that, comprises conical section waveguide (1) and the section waveguide (2) of permanent footpath; Said conical section waveguide (1) links to each other with waveguide device, and its waveguide core xsect is taper, and width reduces to the optical waveguide direction along optical fiber gradually; Form by N waveguide core (3), and along optical fiber to the optical waveguide direction, waveguide core (3) length increases gradually; Gap length between each waveguide core (3) reduces gradually, and this waveguide core (3) is full of clad material all around;

Said permanent footpath section waveguide (2) links to each other with optical fiber, is made up of M the waveguide core (3) with equal length, and the gap length between each waveguide core (3) is identical, and this waveguide core (3) all is full of clad material all around.

2. Planar Optical Waveguide Structures according to claim 1 is characterized in that, said N is at least 3.

3. Planar Optical Waveguide Structures according to claim 1 is characterized in that, said M is 4-15.