CN100409049C

CN100409049C - Optical system including optical waveguide

Info

Publication number: CN100409049C
Application number: CNB2005800173067A
Authority: CN
Inventors: 宫寺信生; 山本礼
Original assignee: Hitachi Chemical Co Ltd
Current assignee: Showa Denko Materials Co ltd
Priority date: 2004-05-28
Filing date: 2005-05-25
Publication date: 2008-08-06
Anticipated expiration: 2025-05-25
Also published as: CN1961231A

Abstract

The invention provides an optical waveguide having an effect resulting from a size reduction such as an increase in the number of fetches, because it has no substantial rise in the manufacturing cost but can reduce the size, and an optical system including the optical waveguide. The optical system includes first, second and third optical input/output means (12, 14 and 16), fourth and fifth multimode optical waveguides (20 and 22) capable of transmitting a light in multiple modes, and optical filter mounting means (26) for mounting an optical filter (24) between the fourth and fifth multimode optical waveguides (20 and 22) in a direction to intersect the traveling direction of the light in the fourth and fifth multimode optical waveguides. The optical system is characterized in that the fourth and fifth multimode optical waveguides (20 and 22) have different widths in a direction perpendicular to the light traveling direction.

Description

The optical system that comprises optical waveguide

Technical field

The present invention relates to comprise the optical system of optical waveguide, more specifically to the optical system that comprises so-called multi-mode interference-type (MMI:Multi-Mode Interference) optical waveguide.

Background technology

Along with being the development of the multimedia communication at beginning with the Internet recently, get up towards wavelength-division multiplex (WDM:Wavelength Division Multiplexing) the Study on Technology prosperity of high speed, high capacity communication.Become having of one of important optics aspect the WDM communication system and will have the photosynthetic of a plurality of wavelength and or the optical multiplexer/demultiplexer that separates constructing.From the viewpoint of cost degradation and miniaturization and high performance, this optical multiplexer/demultiplexer is formed by quartzy (glass) and polymkeric substance etc. on substrate, and actual installation light transceiver device and realize integrated.

As optical multiplexer/demultiplexer, known have filter type, directional coupler type or Mach-Zehnder to interfere type.

For the filter type that helps the module miniaturization, in the past, the known filter type optical multiplexer/demultiplexer that record in the patent documentation 1 (spy opens flat 8-190026 number) etc. is arranged.That is, as shown in figure 19, the filter type optical multiplexer/demultiplexer of record intersects straight line

optical waveguide

401 and 402 in the patent documentation 1, and is provided with light filter 404 at its cross-shaped portion.In this optical multiplexer/demultiplexer, utilize light filter 404 to wavelength transmission and reflection characteristic, and the WDM signal merged or be separated into reflected light and transmitted light.In this filter type optical multiplexer/demultiplexer, need two optical waveguides 401 being designed to 2 θ angle of intersection consistent on the equivalent reflection kernel face 405 of light filter 404 sometimes with 402 optical axes crosspoint 403.Have, in Figure 19, optical waveguide 401,402 and 430 central shaft are expressed as mark 406,407 and 408 respectively again.

In this filter type optical multiplexer/demultiplexer, in the multi-mode interference-type optical waveguide reflecting member is set, for example, representational is light filter.In the catoptrical optical system of utilizing this reflecting member to produce, need reduce the tolerance that position deviation is set to described reflecting member.That is, the position deviation that is provided with reflecting member is that the propagation characteristic of light of this multi-mode interference-type optical waveguide of basis changes must be minimum.Using under the catoptrical situation that reflecting member produced, the position deviation of reflecting member is at least 2 times the light path of incident light to the distance of this reflecting member.Therefore, for guaranteeing enough propagation characteristics, must make the tolerance that position deviation is set of described reflecting member minimum.

Be the problem that the position deviation that solves the reflecting member of the filter type optical multiplexer/demultiplexer of record in the patent documentation 1 produces a very large impact the light propagation efficiency, patent documentation 3 (spy opens 2002-6155 number) has proposed following optical multiplexer/demultiplexer.Promptly, patent documentation 3 has proposed a kind of optical multiplexer/demultiplexer, it is characterized in that, it has the 1st at least, the the 2nd and the 3rd optical waveguide, can carry out the light filter that is provided with on the direct of travel of the 4th optical waveguide that light propagates and the light in described the 4th optical waveguide with multimode crossingly, described the 1st optical waveguide is connected on the 1st end face of described the 4th optical waveguide, the the described the 2nd and the 3rd each optical waveguide is connected to the predetermined position of 2nd end face relative with described the 1st end face of described the 4th optical waveguide, the 1st end face of described the 4th optical waveguide and the 2nd end face be with the 4th optical waveguide respectively in the end face that intersects of the direct of travel of light, described the 4th optical waveguide is the optical waveguide that can carry out the propagation of light with multimode, it is by importing the propagation of the light in described the 4th optical waveguide from the light of the 1st wavelength of arbitrary optical waveguide in the described the 2nd and the 3rd optical waveguide, and the light corresponding with the light input of described the 1st wavelength can be propagated, and from the input of the light of the 2nd wavelength of arbitrary optical waveguide in the described the 2nd and the 3rd optical waveguide through reflection at described light filter, and can make the light propagation corresponding in the optical waveguide that does not have the light input in the described the 2nd and the 3rd optical waveguide with the light input of described the 2nd wavelength.

That is, to shown in Figure 22, patent documentation 3 disclosed optical multiplexer/demultiplexers for example use two kinds of different fluorinated polyimide resins of refractive index to form optical waveguide on silicon (Si) substrate 520 at predetermined substrate 520 as Figure 20.This optical waveguide has the 1st overlayer 521, core zone the 522 and the 2nd overlayer 523 at least and constitutes.Here, the 524th, light filter inserts the groove of usefulness.At this moment, if represent the example of each layer thickness, then the thickness of undercloak 521 is 5 μ m, and the thickness of core 522 is 6.5 μ m, and the thickness of upper cover layer 523 is 15 μ m.Core and tectal refractive index ratio are 0.3%.

As shown in figure 21, close partial wave portion and have multi-mode interference-type optical waveguide 510 and the 1st optical waveguide the 511, the 2nd optical waveguide 512 and the 3rd optical waveguide 513.The width W of multi-mode interference-type optical waveguide is 25 μ m, and length L is 1200 μ m, and between optical waveguide is 5 μ m at interval.In addition, the width of 3 optical waveguides 511,512,513 is 6.5 μ m.

Light filter 515 is that the light to incident angle 0 degree reflects the light of 1.31 μ m and makes the light transmissive dielectric multi-layered film optical filter 515 of wavelength 1.55 μ m.Its thickness is 15 μ m.This dielectric multi-layered film optical filter 515 is common light filters, is inserted in the groove 524 of width 15 μ m at the central portion of multi-mode interference-type optical waveguide, and fixing with UV (ultraviolet ray) (not shown).This groove 524 can be formed by cast-cutting saw.The the 2nd and the 3rd optical waveguide 512,513 is parallel or parallel substantially between mutually with the connecting portion 532 of multi-mode interference-type optical waveguide and 533.

Shown in Figure 21 and 22, the principle of work of the optical multiplexer/demultiplexer of record is that on an end face of multi-mode interference-type optical waveguide, a plurality of optical waveguides are that

optical waveguide

512 and 513 is arranged on predetermined indivedual positions in the patent documentation 3.In the multi-mode interference-type optical waveguide 510, the peak of light along with the preceding of light so that with the direction of the direct of travel quadrature of light on move.

That is, filter configuration is vertical or vertical substantially for the direct of travel with respect to the multimode light that carries out guided wave in the multi-mode interference-type optical waveguide.Its result even arrive described light filter from the light of for example described optical waveguide 513 incidents of optical waveguide, can not become harmful light leak yet and can not produce noise.

Have again, in the optical waveguide that the thin-film optical filters such as light filter that is arranged side by side in the multi-mode interference-type optical waveguide of record in patent documentation 3 uses, because the incident angle of the light of guiding thin-film optical filters is near 0 degree, so can actual eliminate the reflected light in the thin-film optical filters or the Polarization Dependent Loss (PDL:polarization dependent loss) of transmitted light, and, have the effect that can reduce PDL.

On the other hand, in the optical waveguide of utilizing the common multi-mode interference-type optical waveguide (being designated hereinafter simply as MMI) thin-film optical filters etc. is not set and uses, the width of MMI part is certain, and make the incident light waveguide identical with the width of emergent light waveguide, the common central shaft symmetry (for example, opening 2000-22135 number) of position relation of incident light waveguide and emergent light waveguide with reference to patent documentation 2 spies with respect to MMI.This has utilized restrains effect certainly.

Optical system with patent documentation 3 disclosed optical multiplexer/demultiplexers and optical waveguide has solved and must make the difficulty in the minimum manufacturing of the tolerance that position deviation is set of the reflecting member of patent documentation 1 disclosed optical multiplexer/demultiplexer and the problem of consequent manufacturing cost.But the size of optical multiplexer/demultiplexer is bigger, and for the requirement minification on satisfied the use time, the propagation efficiency of light significantly reduces, and optical waveguide each other light leak may take place.

On the other hand, partly be provided with the groove of optical axis vertical direction and be provided with under the situation of thin-film optical filters at MMI as the record in as patent documentation 3, the inventor observes the field of light wave of incident end in suitably convergence of exit end.That is, as patent documentation 3 record, constituting under the situation of channel join-splitting device, existing the wavelength light of answering outgoing to become radiation loss and insert loss and descend, do not answering the light of the wavelength of outgoing to bleed and make in the optical waveguide and isolate the problem that descends at exit end.

Summary of the invention

The present invention its objective is the optical multiplexer/demultiplexer of relative prior art in view of the described problem of the optical multiplexer/demultiplexer of prior art and develop, and provides a kind of and can not improve actual manufacturing cost but can reduce optical system volume, that comprise optical waveguide.

Another object of the present invention provides a kind of optical system that comprises optical waveguide, and this optical waveguide can be guaranteed high light propagation efficiency and reduce the leakage of the light between the optical waveguide and make high-precision optical communication become possibility.

Another purpose of the present invention provides a kind of optical system that comprises optical waveguide, the wavelength light that outgoing does not appear answering in this optical waveguide becomes radiation loss and makes at exit end to be inserted loss and descends, and does not answer the light of the wavelength of outgoing to bleed and make to isolate in the optical waveguide and descend.

The optical system of optical waveguide that comprises of the present invention specifically is constructed as follows.Have, " width of optical waveguide " of the present invention means the core width of optical waveguide again.

(the 1st invention)

A kind of optical system that comprises optical waveguide, it is characterized in that, have the 1st, the the 2nd and the 3rd smooth input and output member and can be with the 4th and the 5th multimode lightguide of multimode propagation light, between the described the 4th and the 5th multimode lightguide, have with the described the 4th and the 5th multimode lightguide in the direct of travel of light the light filter that light filter uses is set crossingly member is set, what the described the 1st smooth input and output member was connected to described the 4th multimode lightguide is provided with the end face of the opposite side of member with described light filter, and what the described the 2nd and the 3rd smooth input and output member was connected to described the 5th multimode lightguide is provided with the end face of the opposite side of member with described light filter;

The the described the 4th and the 5th multimode lightguide different with the width on the direction of the direct of travel quadrature of light.

In the 1st invention, by make the described the 4th and the 5th multimode lightguide different with the width on the direction of the direct of travel quadrature of light, can be with respect to by described light filter reflection and between the described the 2nd and the 3rd smooth input and output member, be coupled, length L 4 and the width W 4 to optimal described the 4th multimode lightguide of light of light that sees through the described the 4th and the 5th both wavelength of multimode lightguide and the main wavelength that only sees through described the 4th multimode lightguide selected in the length L 5 of optimal described the 5th multimode lightguide of light of the main wavelength that only sees through the 5th multimode lightguide and the decision of width W 5 independently, so can realize the compatibility to the characteristic of a plurality of wavelength.Therefore, for example, under the bigger situation of the such employed wavelength difference of light of the light of wavelength 1.31 μ m and wavelength 1.55 μ m, particular significant effect.Particularly, reduce loss through the flashlight of the wavelength of described light filter transmission, and the loss that can increase the light of crosstalking.

In the 1st invention, the 4th and the 5th multimode lightguide with the direction of the direct of travel quadrature of light on width, with other parameter relatively, to giving big influence with the direction of the peaked direct of travel quadrature of light mobile.Therefore, the 1st invention has big design freedom, has the effect that can guarantee high light propagation efficiency.

(the 2nd invention)

It is characterized in that the width on the direction of described the 4th multimode lightguide and direct of travel quadrature light is bigger than the width on the direction of described the 5th multimode lightguide and direct of travel quadrature light.

Mainly big by the width on the direction of described the 4th multimode lightguide and direct of travel quadrature light than the width on the direction of described the 5th multimode lightguide and direct of travel quadrature light, can be with respect to by described light filter reflection and between the described the 2nd and the 3rd smooth input and output member, be coupled, length L 4 and the width W 4 to optimal described the 4th multimode lightguide of light of light that sees through the described the 4th and the 5th both wavelength of multimode lightguide and the main wavelength that only sees through described the 4th multimode lightguide selected in the length L 5 of optimal described the 5th multimode lightguide of light of the main wavelength that only sees through the 5th multimode lightguide and the decision of width W 5 independently, so can realize the compatibility to the characteristic of a plurality of wavelength.

Especially, can suitably reduce by the light filter that described light filter uses is set to the light of the 1st smooth input and output member transmission from the 2nd smooth input and output member the surplus loss that member produces is set.Therefore, for example, at the light of wavelength 1.31 μ m from the 1st smooth input and output member to the 2nd smooth input and output member transmission, and the light of wavelength 1.49 μ m from the 2nd smooth input and output member under the situation of the 1st smooth input and output member transmission, big especially to the effect of the insertion loss of the light of wavelength 1.31 μ m.Particularly, reduce loss through the flashlight of the wavelength of described light filter transmission, and the loss that can increase the light of crosstalking.

(the 3rd invention)

It is characterized in that, with the width on the direction of the direct of travel quadrature of the light of the multimode lightguide that has been connected the light input and output member that the light of answering efficient to propagate best in the light that is input to described the the 1st, the 2nd and the 3rd smooth input and output member is imported, than with the direction of the direct of travel quadrature of the light of other multimode lightguide on width little.

The 3rd invention can constitute multimode lightguide by having described feature, with selectively and low loss ground make the light of answering the propagation of full blast ground in employed a plurality of wavelength according to the purposes transmission.

In addition, though light in optical waveguide not with the direction of the direct of travel quadrature of light on diffusion significantly, at light filter member being set is in the space, has the tendency of diffusion significantly on same direction.Therefore, in the 3rd invention, the light that incides light input and output member can be from inciding the big multimode lightguide of direction width with the direct of travel quadrature of light with the little multimode lightguide efficient of the direction width of the direct of travel quadrature of light well, and have the effect of the light propagation efficiency that can keep high.

(the 4th invention)

It is characterized in that, described the 4th multimode lightguide with the direction of the direct of travel quadrature of light on width and described the 5th multimode lightguide with the direction of the direct of travel quadrature of light on width be more than the 5 μ m below the 20 μ m.

In the 4th invention, width on the direction of the width on the direction of described the 4th multimode lightguide and direct of travel quadrature light and described the 5th multimode lightguide and direct of travel quadrature light surpasses under the situation of 20 μ m, exists along the elongated problem of length of the direct of travel of the light of the optical system that comprises optical waveguide.Under the situation of the discontented 5 μ m of width on the direction of the width on the direction of described the 4th multimode lightguide and direct of travel quadrature light and described the 5th multimode lightguide and direct of travel quadrature light, need to increase the refractive index ratio of overlayer and core for constituting multimode lightguide, and can not use common single-mode fiber to be used as light input and output member.Otherwise, even use common single-mode fiber to be used as light input and output member, also exist coupling loss excessive, and the problem that light is propagated.

In the 4th invention, be discontented with under the situation of 5 μ m at the width of multimode lightguide, big with the coupling loss change of the light input and output member that is connected to this multimode lightguide, the result causes inserting the increase of loss.Width at multimode lightguide surpasses under the situation of 20 μ m, and it is big that the length of this multimode lightguide becomes, and this part optical waveguide components size is elongated.When the optical waveguide components size was elongated, transmission loss (TL) increased this amount, and the result will cause inserting the increase of loss.

(the 5th invention)

The the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every 1/2 different to the interval of the input and output center of described the 4th multimode lightguide to the center line of the input and output position of described the 5th multimode lightguide with the 1st smooth input and output member with the 2nd and the 3rd smooth input and output member.

In the 5th invention, by make the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every 1/2 different to the interval of the input and output center of described the 4th multimode lightguide to the center line of the input and output position of described the 5th multimode lightguide with the 1st smooth input and output member with the 2nd and the 3rd smooth input and output member, can be with respect to by described light filter reflection and between the described the 2nd and the 3rd smooth input and output member, be coupled, the centreline space of the input and output position of optimal the described the 2nd and the 3rd smooth input and output member of light of the main wavelength that only sees through the 5th multimode lightguide every the decision of 1/2D select independently light the optimal the 2nd and the 3rd smooth input and output member of the light that sees through the described the 4th and the 5th both wavelength of multimode lightguide and the main wavelength that only sees through described the 4th multimode lightguide to the center line of the input and output position of described the 5th multimode lightguide and the 1st smooth input and output member to the interval of the input and output center of described the 4th multimode lightguide, so can realize compatibility to the characteristic of a plurality of wavelength.So can realize compatibility to the characteristic of a plurality of wavelength.Therefore, for example, under the bigger situation of the such employed wavelength difference of light of the light of wavelength 1.31 μ m and wavelength 1.55 μ m, particular significant effect.Specifically, reduce loss through the flashlight of the wavelength of described light filter transmission, and the loss that can increase the light of crosstalking.

In the 5th invention, with the 2nd, the 3rd smooth input and output member as the curve optical waveguide, when enlarging the interval between two input and output members, with the 1st smooth input and output member during as optical fiber and straight line optical waveguide, owing to can obtain optimal coupling loss, so with whole input and output members are compared as the situation of curve optical waveguide, can reduce size.Can reduce transmission loss (TL) by reducing size, the result can reduce the insertion loss.

In the 5th invention, be under the situation of linearity optical waveguide or optics making the 1st smooth input and output member, have bigger design freedom, and have the effect that can guarantee high light propagation efficiency.Have, in the 5th invention, light input and output member is not straight again, has that light leak from a light input and output member incides another light input and output member and the effect that may reduce that contains unwanted signals.

(the 6th invention)

In the width of the direction of the width of the direction of the described the 1st smooth input and output member and direct of travel quadrature light and the described the 2nd and the 3rd smooth input and output member and direct of travel quadrature light at least one is different.

According to the 6th invention, can be with respect to between the described the 2nd and the 3rd smooth input and output member, being coupled, the decision of the width of the direction of the direct of travel quadrature of the light of optimal the described the 2nd and the 3rd smooth input and output member of light of the main wavelength that only sees through the 5th multimode lightguide is selected independently to light the optimal the 1st smooth input and output member of light that sees through the described the 4th and the 5th both wavelength of multimode lightguide and the main wavelength that only sees through described the 4th multimode lightguide width to the direction of the direct of travel quadrature of the light of described the 4th multimode lightguide, so can realize the compatibility to the characteristic of a plurality of wavelength.Therefore, for example, under the bigger situation of the such employed wavelength difference of light of the light of wavelength 1.31 μ m and wavelength 1.55 μ m, particular significant effect.Specifically, reduce the loss of flashlight to the wavelength of the described light filter transmission of process, and the loss that can increase the light of crosstalking.

In the 6th invention, with the 2nd, the 3rd smooth input and output member as the curve optical waveguide, when enlarging the interval between two input and output members, with the 1st smooth input and output member during as optical fiber and straight line optical waveguide, owing to can obtain optimal coupling loss, so with whole input and output members are compared as the situation of curve optical waveguide, can reduce size.Can reduce transmission loss (TL) by reducing size, the result can reduce the insertion loss.

In the 6th invention, be under the situation of linearity optical waveguide or optics making the 1st smooth input and output member, have bigger design freedom, and have the effect that can guarantee high light propagation efficiency.

(the 7th invention)

It is characterized in that, the described the 1st smooth input and output member with the direction of the direct of travel quadrature of light on width than the described the 2nd and the 3rd smooth input and output member with the direction of the direct of travel quadrature of light on width at least one is little.

(8a invention)

It is characterized in that, the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every 1/2 different to the interval of the input and output center of described the 4th multimode lightguide to the center line of the input and output position of described the 5th multimode lightguide with the 1st smooth input and output member with the 2nd and the 3rd smooth input and output member.

(8b invention)

The described the 3rd smooth input and output member with the direction of the direct of travel quadrature of light on width and the described the 2nd smooth input and output member with the direction of the direct of travel quadrature of light on width different.

(the 9th invention)

It is characterized in that, the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every the 1/2 to the 2 and the 3rd smooth input and output member big to the center line and the 1st smooth input and output member of the input and output position of described the 5th multimode lightguide to the interval of the input and output center of described the 4th multimode lightguide.

By having described feature, the 9th invention can enlarge the gap between the 2nd and the 3rd smooth input and output member.Because the 2nd and the 3rd smooth input and output member is very approaching usually, so forming with optical waveguide under the situation of these input and output members, the gap of the 2nd and the 3rd smooth input and output member is narrow, and manufacture deviation also becomes big to the influence of characteristic.But,, can avoid this problem, and can realize making the optical waveguide of stability of characteristics according to the 9th invention.

The 9th invention also has bigger design freedom, and has the effect that can guarantee high light propagation efficiency.Have, in the 9th invention, light input and output member is not straight again, has that light leak from a light input and output member incides another light input and output member and the effect that may reduce that contains unwanted signals.

(9a invention)

The center line that on the center line that extends on the direct of travel of the light of the 4th multimode lightguide departs from direct of travel at the light of the 5th multimode lightguide, extends.

(9b invention)

The center line that extends on the direct of travel of the light of the 4th multimode lightguide departs from the center line of the 2nd and the 3rd smooth input and output member to the input and output position of the 5th multimode lightguide.

(the 10th invention)

Described light filter makes the 1st transmitted light and the 2nd transmitted light transmission and the 3rd reflected light is reflected, incide the 2nd smooth input and output member and be suppressed from the 1st transmitted light of the 1st smooth input and output member incident, incide the 3rd smooth input and output member and be suppressed to the 1st and the 2nd smooth input and output member incident from the 3rd reflected light of the 2nd smooth input and output member incident to the 1st and the 3rd smooth input and output member incident; From the 2nd transmitted light of the 2nd smooth input and output member incident to the 1st smooth input and output member incident and be suppressed to the 2nd and the 3rd smooth input and output member incident.

In described explanation, " inhibition incident " means to compare with the light input and output member of incident and suppresses incident fully.Specifically, according to the kind of signal, propagation distance etc., what the ratio of incident light quantity was desirable is more than the 10dB.Better is more than the 25dB.

In the 10th invention, optical system is by being disposed at family's side of FTTH (Fiber To The Home), the 1st smooth input and output member is connected to ONU (Optical Network Unit), the 2nd smooth input and output member is connected to optical fiber from office's side, the 3rd smooth input and output member is connected to V-ONU (Video ONU), and the system that receives data communication and Image Communication with 1 core fibre simultaneously can be provided.

Under this situation, by having the feature of described formation, can reduce the loss of data-signal, and can reduce the degree of sneaking into data-signal in the picture signal.

According to the 10th invention, can make light incide predetermined light input and output member effectively, and have and to realize that light utilization ratio height and light propagates the effect of the high optical communication of precision from light input and output member.

(the 11st invention)

Described light filter makes the 1st transmitted light and the 2nd transmitted light transmission and with the reflection of the 3rd reflected light, incides the 2nd smooth input and output member and is suppressed to the 1st and the 3rd smooth input and output member incident from the 2nd transmitted light of the 1st smooth input and output member incident;

Incide the 1st smooth input and output member and be suppressed from the 1st transmitted light of the 2nd smooth input and output member incident to the 2nd and the 3rd smooth input and output member incident, from the 3rd reflected light of the 3rd smooth input and output member incident to the 2nd smooth input and output member incident and be suppressed to the 1st and the 3rd smooth input and output member incident.

In the 11st invention, be disposed at family's side of FTTH, the 1st smooth input and output member is connected to OLT (Optical Line Terminal), the 2nd smooth input and output member is connected to optical fiber from office's side, the 3rd smooth input and output member is connected to V-OLT (Video OLT), sends the two-way communication of data and the system that image sends simultaneously thereby can provide with 1 core fibre.Under this situation, the loss of data-signal can be reduced, and the harmful effect of data-signal can be reduced the transmission of picture signal.

According to the 11st invention, can incide predetermined light input and output member effectively from the light of light input and output member, and have and realize that light utilization ratio height and light propagates the effect of the high optical communication of precision.

(the 12nd invention)

A kind of optical system, it is a pair of that it becomes the optical system of the optical system of the 10th invention and the 11st invention, and between the 2nd smooth input and output member by coupling optically such as optical fiber.

(the 13rd invention)

Described light filter makes the reflection of the 1st reflected light and the 2nd reflected light and with the 3rd transmitted light transmission,

Incide the 3rd smooth input and output member and be suppressed from the 2nd reflected light of the 2nd smooth input and output member incident, incide the 1st smooth input and output member and be suppressed to the 2nd and the 3rd smooth input and output member incident from the 3rd transmitted light of the 2nd smooth input and output member incident to the 1st and the 2nd smooth input and output member incident;

From the 1st reflected light of the 3rd smooth input and output member incident to the 2nd smooth input and output member incident and be suppressed to the 1st and the 3rd smooth input and output member incident.

According to the 13rd invention, by the family side of optical system configurations in FTTH, the 3rd smooth input and output member is connected to ONU, the 2nd smooth input and output member is connected to optical fiber from office's side, the 3rd smooth input and output member is connected to V-ONU (Video ONU), thereby the system that receives data communication and Image Communication with 1 core fibre simultaneously can be provided.Under this situation, by having the feature of described formation, can reduce the loss of data-signal, and can reduce the degree of sneaking into data-signal in the picture signal.

According to the 13rd invention, can incide predetermined light input and output member effectively from the light of light input and output member, and have and realize that light utilization ratio height and light propagates the effect of the high optical communication of precision.

(the 14th invention)

Incide the 2nd light output member and be suppressed from the 3rd transmitted light of the 1st smooth input and output member incident to the 1st and the 3rd smooth input and output member incident;

Incide the 3rd smooth input and output member and be suppressed from the 1st reflected light of the 2nd input and output member incident to the 1st and the 2nd smooth input and output member incident;

From the 2nd reflected light of the 3rd smooth input and output member incident to the 2nd smooth input and output member incident and be suppressed to the 1st and the 3rd smooth input and output member incident.

According to the 14th invention, by the office side of optical system configurations in FTTH, the 3rd smooth input and output member is connected to OLT (Optical Line Terminal), the 2nd smooth input and output member is connected to optical fiber from family's side, the 1st smooth input and output member is connected to V-OLT (Video OLT), sends the two-way communication of data and the system that image sends simultaneously thereby can provide with 1 core fibre.Under this situation, the loss of data-signal can be reduced, and the harmful effect of data-signal can be reduced the transmission of picture signal.

According to the 14th invention, can incide predetermined light input and output member effectively from the light of light input and output member, and have and realize that light utilization ratio height and light propagates the effect of the high optical communication of precision.

(the 15th invention)

A kind of optical system, it is a pair of that it becomes the optical system of the optical system of the 13rd invention and the 14th invention, and between the 2nd smooth input and output member by coupling optically such as optical fiber.

(the 16th invention)

A kind of optical system, it is a pair of that it becomes the optical system of the optical system of the 10th invention and the 14th invention, and between the 2nd smooth input and output member by coupling optically such as optical fiber.

(the 17th invention)

A kind of optical system, it is a pair of that it becomes the optical system of the optical system of the 11st invention and the 13rd invention, and between the 2nd smooth input and output member by coupling optically such as optical fiber.

(the 18th invention)

Length on the direct of travel of the described the 4th and the 5th multimode lightguide at light is being set at L respectively ₄And L ₅The time,

100μm≤L ₄+L ₅≤800μm

50μm≤L ₄+L ₅≤400μm

In the 18th invention, at L ₅Under the situation of discontented 50 μ m, not only multimode lightguide close the partial wave scarce capacity, and can not carry out through the 5th multimode lightguide transmission and by the suitable propagation of the light of light filter reflection.Insertion loss between the 2nd and the 3rd smooth input and output member increases, and simultaneously, the back light change is big and system is unstable.

At L ₅Surpass under the situation of 400 μ m, the optical waveguide components size is elongated.Therefore cause the increase of transmission loss (TL).

At L ₄+ L ₅Under the situation of discontented 100 μ m, not only multimode lightguide close the partial wave scarce capacity, and can not carry out through the 4th and the 5th multimode lightguide transmission and by the suitable propagation of the light of light filter reflection.

At L ₄+ L ₅Surpass under the situation of 800 μ m, the optical waveguide components size is elongated.Therefore cause the increase of transmission loss (TL).

According to the 18th invention, can dwindle multimode lightguide light direct of travel length and can realize less optical system, and have volume production efficiently and can reduce the effect of the manufacturing cost of optical system.

(the 19th invention)

A kind of optical system that comprises the optical waveguide of the 1st～the 18th invention is characterized in that the the 1st, the 2nd and the 3rd smooth input and output member is monomode optical waveguide.

(the 20th invention)

A kind of optical system that comprises the optical waveguide of the 1st～the 18th invention is characterized in that the 1st smooth input and output member is an optical fiber, and the 2nd and the 3rd smooth input and output member is monomode optical waveguide.

(the 21st invention)

The optical system that comprises described optical waveguide is at described light filter the optical multiplexer/demultiplexer that light filter is set on the member to be set.

Light filter can be only to make the light transmissive wavelength of expectation wavelength select light filter, also can be catoptron, can also be half-reflecting mirror, can be again can be by applying the light absorption light filter that electric field waits the absorption of regulating light.

According to the optical system that comprises optical waveguide of the present invention, the relative optical multiplexer/demultiplexer of prior art is not because the actual cost of making rises but can dwindle size, so have the effects that miniaturization produced such as output increase that make from a substrate.

According to the optical system that comprises optical waveguide of the present invention, have to provide and comprise and to guarantee high light propagation efficiency and reduce the mutual light of optical waveguide to leak and make the high precision optical communication become the optical system of possible optical waveguide.

According to the optical system that comprises optical waveguide of the present invention, have and eliminated the wavelength light of answering outgoing and become radiation loss and insert loss at exit end and descend, do not answer the light of the wavelength of outgoing to bleed in the optical waveguide and make and isolate the effect that descends.

Embodiment

Come with reference to the accompanying drawings below to describe to being used to implement optimal way of the present invention.

(the 1st embodiment)

Its MMI of optical system that comprises disclosed existing optical waveguides such as patent documentation 3 partly is certain width.In the 1st embodiment, the width of MMI part is constituted in thin-film optical filters both sides difference.

In the structure that makes up with thin-film optical filters on the simple structure ground that only will have MMI now, the reason of the phenomenon that performance descends is, different at the slot part that inserts thin-film optical filters with adjacent MMI part, do not have overlayer with respect to core on above-below direction and left and right directions, the sealing effect of light wave disappears.The perturbation of consequent light wave fields can think that the field shape to the convergence light of exit end exerts an influence.So, the 1st embodiment by make structure the most suitableization bear the field of the propagates light among the MMI of perturbation with compensation, perhaps meet field shape that restrain light, dispose the incident light waveguide to the convergence position and the emergent light waveguide solves problem.That is, the thin-film optical filters of MMI part makes the field shape of bearing transmission or the perturbation of reflection back approach not insert the state of thin-film optical filters by the width of adjusting the MMI part.

The optical system that comprises optical waveguide 10 of the 1st embodiment, the width of the direction of its described the 4th and the 5th multimode lightguide and direct of travel quadrature light is different, and the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every 1/2 different to the interval of the input and output center of described the 4th multimode lightguide to the center line of the input and output position of described the 5th multimode lightguide with the 1st smooth input and output member with the 2nd and the 3rd smooth input and output member.

As shown in Figure 1, the formation of the optical system that comprises optical waveguide 10 of the 1st embodiment has the 1st smooth input and output member 12, the 2nd smooth input and output member 14 and the 3rd smooth input and output member 16, can be with the 4th multimode lightguide 20 and the 5th multimode lightguide 22 of multimode propagation light, between described the 4th multimode lightguide 20 and the 5th multimode lightguide 22, have with described the 4th multimode lightguide 20 and the 5th multimode lightguide 22 in the direct of travel of light light filter that light filter 24 usefulness are set crossingly member 26 is set, what the described the 1st smooth input and output member 12 was connected to described the 4th multimode lightguide 20 is provided with the end face of member 26 opposite sides with described light filter, and what the described the 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 were connected in described the 5th multimode lightguide 22 is provided with the end face of member 26 opposite sides with described light filter.

The 1st smooth input and output member the 12, the 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 are monomode optical waveguides.The 1st smooth input and output member 12 also can be an optical fiber.

The length of the direct of travel of the light of described the 4th multimode lightguide 20 is made as L ₄, and will be made as W with the width of the direction of the direct of travel quadrature of light ₄The length of the direct of travel of the light of described the 5th multimode lightguide 22 is made as L ₅, and will be made as W with the width of the direction of the direct of travel quadrature of light ₅

With the 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 to the centreline space of the input and output position of described the 5th multimode lightguide 22 every 1/2 be made as D ₅Center line O and the 1st smooth input and output member 12 to the input and output position of described the 5th multimode lightguide 22 is made as D to the interval of the input and output center of described the 4th multimode lightguide 4 with the 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 ₄In the present embodiment, center line O is consistent with the center line of the 4th and the

5th multimode lightguide

20,22.

Light filter 24 uses the light for incident angle 0 degree to make the transmittance of the 1st wavelength 1.31 μ m and the 2nd wavelength 1.49 μ m and with the dielectric multi-layered film optical filter 24 of the light reflection of wavelength 1.55 μ m.It can be used for the optical system of described the 1st invention, the 2nd invention, the 3rd invention.

Light filter thickness is 25 μ m.Substrate is 0.1 to 1.0mm glass substrate or the polyimide substrate of 5 to 10 μ m.Also can make the light filter that does not have substrate, and can use in the present invention.

As light filter 24, can use light for incident angle 0 degree to make the light reflection of the 1st wavelength 1.31 μ m and the 2nd wavelength 1.49 μ m and with the light transmissive dielectric multi-layered film optical filter 24 of wavelength 1.55 μ m.It can be used for the optical system of described the 4th invention, the 5th invention, the 6th invention.

Each size of the optical system that comprises optical waveguide 10 of the 1st embodiment is as follows:

The length of the direct of travel of the light of the 4th multimode lightguide 20: L ₄=412.5 μ m

The length of the direct of travel of the light of the 5th multimode lightguide 22: L ₅=242.5 μ m

The 4th multimode lightguide 20 and the width direct of travel orthogonal directions: W ₄=17.2 μ m

The 5th multimode lightguide 22 and the width direct of travel orthogonal directions: W ₅=16.8 μ m

The 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 are to the center line O of the input and output position of described the 5th multimode lightguide 22 and the 1st smooth input and output member 12 interval to the input and output center of described the 4th multimode lightguide 4: D ₄=4.7 μ m

The 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 to the centreline space of the input and output position of described the 5th multimode lightguide 22 every 1/2:D ₅=5.15 μ m

The the 1st～the 3rd smooth input and output member width with direct of travel orthogonal directions light 12,14,16: 6.2 μ m

The superfluous loss of the optical waveguide of the optical system that comprises optical waveguide 10 of the 1st embodiment is as follows:

From the 1st smooth input and output member to the 2 smooth input and output members (wavelength 1.31 μ m) :-0.6dB

From the 1st smooth input and output member to the 3 smooth input and output members (wavelength 1.31 μ m) :-49dB

From the 2nd smooth input and output member to the 1 smooth input and output member (wavelength 1.49 μ m) :-0.6dB

(the 2nd embodiment)

The 2nd embodiment makes the width W of MMI part constitute in thin-film optical filters both sides difference.

In addition, make is that the incident light waveguide of symmetry and the position relation of emergent light waveguide are asymmetric with respect to the MMI central shaft in the past.

The formation of the optical system that comprises optical waveguide 110 of the 2nd embodiment is marked with same tag and omits its explanation for the formation identical with the optical system that comprises optical waveguide 10 of the 1st embodiment as shown in Figure 2.

The optical system that comprises optical waveguide 110 of the 2nd embodiment, its width W with the direction of the direct of travel quadrature of the light of the 4th and the 5th multimode lightguide equates, and the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every 1/2D ₅With the 2nd and the 3rd smooth input and output member to the center line of the input and output position of described the 5th multimode lightguide and the 1st smooth input and output member interval D to the input and output center of described the 4th multimode lightguide ₄Different.

Each size of the optical system that comprises optical waveguide 110 of the 2nd embodiment is as follows:

The 4th multimode lightguide 20 and the width direct of travel orthogonal directions: W ₄=16.8 μ m

Other formation and size are identical with the 1st embodiment.

The superfluous loss of the optical waveguide of the optical system that comprises optical waveguide 10 of the 2nd embodiment is as follows:

From the 1st smooth input and output member to the 2 smooth input and output members (wavelength 1.31 μ m) :-0.7dB

From the 1st smooth input and output member to the 3 smooth input and output members (wavelength 1.31 μ m) :-29dB

From the 2nd smooth input and output member to the 1 smooth input and output member (wavelength 1.49 μ m) :-0.7dB

(the 3rd embodiment)

The formation of the optical system that comprises optical waveguide 210 of the 3rd embodiment is marked with same tag and omits its explanation for the formation identical with the optical system that comprises optical waveguide 10 of the 1st embodiment as shown in Figure 3.

The optical system that comprises optical waveguide 210 of the 3rd embodiment, its width W with the direction of the direct of travel quadrature of the light of the 4th and the 5th multimode lightguide is different, and the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every 1/2D ₅With the 2nd and the 3rd smooth input and output member to the center line of the input and output position of described the 5th multimode lightguide and the 1st smooth input and output member interval D to the input and output center of described the 4th multimode lightguide ₄Equate.

Each size of the optical system that comprises optical waveguide 210 of the 3rd embodiment is as follows:

Other formation and size are identical with the 1st embodiment.

The 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 are to the center line O of the input and output position of described the 5th multimode lightguide 22 and the 1st smooth input and output member 12 interval to the input and output center of described the 4th multimode lightguide 4: D ₄=5.15 μ m

The superfluous loss of the optical waveguide of the optical system that comprises optical waveguide 210 of the 3rd embodiment is as follows:

From the 1st smooth input and output member to the 2 smooth input and output members (wavelength 1.31 μ m) :-0.9dB

From the 1st smooth input and output member to the 3 smooth input and output members (wavelength 1.31 μ m) :-26dB

(the 4th embodiment)

The width W to the width W of the incident light waveguide of MMI and emergent light waveguide for same widths is different to be constituted by making in the past.The 4th embodiment constitute will be connected to the width adjustment of emergent light waveguide part of MMI be to bear through field shape of the thin-film optical filters of MMI part or the perturbation after the reflection and different with the optical waveguide that is connected to incident end width partly.So constitute the coupling loss that has reduced MMI part and emergent light waveguide part.For example, be conceived to from the 1st smooth input and output member under the situation of the light that the 2nd smooth input and output member is propagated, be conceived to from the 2nd smooth input and output member under the situation of the light that the 3rd smooth input and output member is propagated, and be conceived to from the 3rd smooth input and output member under the situation of the light that the 2nd smooth input and output member is propagated, make the width difference of these light input and output members, it is desirable to make the width of exiting side bigger than the width of light incident side.

The formation of the optical system that comprises optical waveguide 310 of the 4th embodiment is marked with same tag and omits its explanation for the formation identical with the optical system that comprises optical waveguide 10 of the 1st embodiment as shown in Figure 4.

The optical system that comprises optical waveguide 310 of the 4th embodiment, at least one is different in the width W of the direction of the width W of its described the 1st smooth input and output member and direct of travel orthogonal directions light and the 2nd and the 3rd smooth input and output member and direct of travel quadrature light, and it is desirable to, the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every 1/2D ₅Different with the 1st smooth input and output member with the 2nd and the 3rd smooth input and output member to the interval of the input and output center of described the 4th multimode lightguide to the center line of the input and output position of described the 5th multimode lightguide.

As shown in Figure 4, the data of the optical system that comprises optical waveguide 310 of the 4th embodiment are as follows.The described the 1st width with direct of travel orthogonal directions light smooth input and output member 12 is made as W ₁, the 2nd width with direct of travel orthogonal directions light smooth input and output member 14 is made as W ₂, the 3rd width with direct of travel orthogonal directions light smooth input and output member 16 is made as W ₃

The width of the 1st smooth input and output member and direct of travel orthogonal directions light: W ₁=6.2 μ m

The width of the 2nd smooth input and output member and direct of travel orthogonal directions light: W ₂=6.4 μ m

The width of the 3rd smooth input and output member and direct of travel orthogonal directions light: W ₃=6.4 μ m

The length of the direct of travel of the light of the 4th multimode lightguide 20: L ₄=445 μ m

The length of the direct of travel of the light of the 5th multimode lightguide 22: L ₅=274 μ m

The 4th multimode lightguide 20 and the width direct of travel orthogonal directions: W ₄=18.2 μ m

The 5th multimode lightguide 22 and the width direct of travel orthogonal directions: W ₅=18.2 μ m

The 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 are to the center line O of the input and output position of described the 5th multimode lightguide 22 and the 1st smooth input and output member 12 interval to the input and output center of described the 4th multimode lightguide 20: D ₄=4.44 μ m

The 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 to the centreline space of the input and output position of described the 5th multimode lightguide 22 every 1/2:D ₅=5.2 μ m

The superfluous loss of the optical waveguide of the optical system that comprises optical waveguide 410 of the 4th embodiment is as follows:

From the 1st smooth input and output member to the 3 smooth input and output members (wavelength 1.31 μ m) :-55dB

From the 2nd smooth input and output member to the 1 smooth input and output member (wavelength 1.49 μ m) :-0.8dB

(the 5th embodiment)

The optical system that comprises optical waveguide 320 of the 5th embodiment shown in Figure 5, it makes from the distance D of the input and output center of center line O1 to the 2 smooth input and output members 14 of the 4th multimode lightguide 20 ₆With distance D to the input and output center of the 3rd smooth input and output member 16 ₇Different.The center line of the 5th multimode lightguide 22 is consistent with the center line O1 of the 4th multimode lightguide 20.

The embodiment of the optical system that comprises optical waveguide 320 of the 5th embodiment is as follows:

The center line O1 of the 4th and the

5th multimode lightguide

20,22 and the 1st smooth input and output member 12 are to the interval of the input and output center of the 4th multimode lightguide 20: D ₄=4.44 μ m

The center line O1 of the 4th and the

5th multimode lightguide

20,22 and the 2nd smooth input and output member 14 are to the interval of the input and output center of the 5th multimode lightguide 22: D ₆=5.15 μ m

The center line O1 of the 4th and the

5th multimode lightguide

20,22 and the 3rd smooth input and output member 16 are to the interval of the input and output center of the 5th multimode lightguide 22: D ₇=5.25 μ m

This embodiment makes the 2nd and the 3rd smooth input and output member depart from respect to the center line O1 of the 4th multimode lightguide 20 to the center line O of the input and output position of the 5th multimode lightguide 22.

The superfluous loss of the optical waveguide of the optical system 320 of described embodiment is as follows:

From the 2nd smooth input and output member to the 3 smooth input and output members (wavelength 1.55 μ m) :-0.4dB

From the 2nd smooth input and output member to the 2 smooth input and output members (wavelength 1.55 μ m) :-43dB

From this embodiment as can be known, by making D ₆And D ₇Differently constitute, can reduce from the superfluous loss of the optical waveguide of the 2nd smooth input and output member 14 to the 3rd smooth input and output members 16.

Therefore, can near (ア Network セス) be the optical system that comprises optical waveguide of using the 5th embodiment in the optical communication, especially, can suitably be used in upstream data. signals and to use 1.31 mum wavelength bands, in downlink data signal, use 1.49 mum wavelength bands, in downstream video signal, use the optical communication system of 1.55 mum wavelength bands.

In addition, in described embodiment, can only make the width W of the 3rd smooth input and output member and direct of travel orthogonal directions light ₃Become 7.4 μ m or 8.4 μ m from 6.4 μ m.W is arranged again ₃During=8.4 μ m, the core of the 3rd smooth input and output member 16 is crossed over the core of the 5th multimode lightguide 22 and is extended (with reference to Figure 11) on Width.In the width W that increases the 3rd smooth input and output member 16 ₃Situation under, the surplus loss of the light of the wavelength 1.55 μ m that propagate to the 3rd smooth input and output member from the 2nd smooth input and output member 14 of optical system 320, with described embodiment relatively, respectively at W ₃Under the situation of=7.4 μ m and W ₃Further reduce 0.01dB under the situation of=8.4 μ m.By adjusting the width W of the 3rd smooth input and output member 16 and direct of travel orthogonal directions light as so ₃And can further reduce from the surplus loss of the 2nd smooth input and output member 14 to the light of the 3rd smooth input and output member propagation.

(the 6th embodiment)

The optical system 330 that comprises the 6th embodiment shown in Figure 6, the center line O2 of the 5th multimode lightguide 22 with respect to the center line O1 of the 4th multimode lightguide 20 with the direction of the direct of travel quadrature of light on depart from, from the distance D of the input and output center of center line O2 to the 2 smooth input and output members 14 of the 5th multimode lightguide 22 ₈Distance D with the input and output center of the 3rd smooth input and output member 16 ₉Different.

(the 7th embodiment)

Comprise the optical system 340 of the 7th embodiment shown in Figure 7 and comprise that the optical system 330 of the 6th embodiment is same, the center line O2 of the 5th multimode lightguide 22 with respect to the center line O1 of the 4th multimode lightguide 20 with the direction of the direct of travel quadrature of light on depart from, from the distance D of the input and output center of center line O2 to the 2 smooth input and output members 14 of the 5th multimode lightguide 22 ₈With distance D to the input and output center of the 3rd smooth input and output member 16 ₉Different.The 5th multimode lightguide 22 surmounts the 4th multimode lightguide 20 and exists on the direction that its center line O2 is departed from.

Shown in the 6th embodiment and the 7th embodiment, center line O2 by the 5th multimode lightguide 22 departs from respect to the center line O1 of the 4th multimode lightguide 20, can reduce the superfluous loss of optical waveguide between the 1st smooth input and output member 12 and the 2nd smooth input and output member 14, and can increase from the 1st smooth input and output member to the superfluous loss of the optical waveguide of the 3rd smooth input and output member 16 and suppress to crosstalk.

(design sequence)

In the 1st embodiment, the Design for optical system order that comprises optical waveguide of the present invention initial shown in Fig. 5 multimode lightguide mirror image figure of Fig. 8 as, light filter 24 is assumed to catoptron, form the mirror image of the 5th multimode lightguide the 22, the 2nd smooth input and output member 14 and the 3rd smooth input and output member 16, i.e. the 5th multimode lightguide mirror image 22M, the 2nd smooth input and output member mirror image 14M and the 3rd smooth input and output member mirror image 16M.In the formation shown in the 5th multimode lightguide mirror image figure of Fig. 8, incide the 3rd smooth input and output member mirror image 1 6M for making from the 3rd reflected light of the 2nd smooth input and output member 14 incidents the biglyyest, and incide the 2nd smooth input and output member mirror image 14M from the 3rd reflected light of the 2nd smooth input and output member 14 minimumly, determine the length L of direct of travel of the light of the 5th multimode lightguide 22 ₅, with the width W of the direct of travel orthogonal directions of light ₅And the 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 to the centreline space of the input and output position of the 5th multimode lightguide 22 every 1/2D ₅

Further improving from the 2nd smooth input and output member 14 incidents and inciding under the situation of the 3rd catoptrical light quantity of the 3rd smooth input and output member 16, further adjusting the width W of the 3rd smooth input and output member mirror image 16M direction with direct of travel quadrature light (the 3rd smooth input and output member 16) ₃, for example, as shown in Figure 9, increase its width W ₃Like this, can further reduce to propagate into the loss of the light quantity of the 3rd smooth input and output member from the 2nd smooth input and output member.

In contrast, further improving from the 3rd smooth input and output member 16 incidents and inciding under the situation of light quantity of light of the 2nd smooth input and output member 14, further adjusting the width W of the direction of the 2nd smooth input and output member 14 and direct of travel quadrature light ₂, for example, increase its width W ₂Like this, can further reduce to propagate into the loss of the light quantity of the 2nd smooth input and output member 14 from the 3rd smooth input and output member 16.

When adjusting the width of the 2nd or the 3rd smooth input and output member directions with direct of

travel quadrature light

14,16, for preventing that the coupling loss that is connected the place, place between the 2nd or the 3rd smooth input and

output member

14,16 and the optical fiber from increasing, it is desirable to adjust gradually the 2nd or the 3rd smooth input and

output member

14,16 with direct of travel quadrature light width and with the mode diameter that the place, place is integrated into optical fiber that is connected of optical fiber.For example, as shown in figure 10,, when enlarging the width of the 3rd smooth input and output member 16, the width of the 3rd smooth input and output member 16 is dwindled gradually to optical fiber F locating with the place that is connected of the 5th multimode lightguide 22.

Then, except the length L of the direct of travel of the light of fixed the 5th multimode lightguide 22 ₅, with the width W of the direct of travel orthogonal directions of light ₅And the 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 to the centreline space of the input and output position of the 5th multimode lightguide 22 every 1/2D ₅Outside, as Fig. 1～shown in Figure 7, form the 1st smooth input and output member 12 and the 4th multimode lightguide 20.In this constitutes, incide the 2nd smooth input and output member 14 for making from the 1st transmitted light or the 2nd transmitted light of the 1st smooth input and output member 12 incidents the biglyyest, and incide the 3rd smooth input and output member 16 minimumly, determine the length L of direct of travel of the light of the 4th multimode lightguide 20 ₄, with the width W of the direct of travel orthogonal directions of light ₄And the 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 to the center line O of the input and output position of the 5th multimode lightguide 22 and the 1st smooth input and output member 12 interval D to the input and output center of the 4th multimode lightguide 4 ₄Deng.

In the width W that increases the 3rd smooth input and output member 16 ₃Situation under, for example shown in Figure 11, the 3rd smooth input and output member 16 can surmount the core of the 5th multimode lightguide 22 and extend on Width.Similarly, in the width W that increases the 2nd smooth input and output member 14 ₂Situation under, for example shown in Figure 12, the 2nd smooth input and output member 14 can surmount the core of the 5th multimode lightguide 22 and extend on Width.

(comparative example)

The optical system that comprises optical waveguide 360 of comparative example, the width of the direction of the direct of travel quadrature of its described the 4th and the 5th multimode lightguide and light optical waveguide equates, and, the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every the center line of the 1/2 and the 2 3rd smooth input and output member to the input and output position of described the 5th multimode lightguide equate to the interval of the input and output center of described the 4th multimode lightguide with the 1st smooth input and output member.

As shown in figure 13, the optical system that comprises optical waveguide 360 of comparative example is as follows.Formation for identical with the optical system that comprises optical waveguide 10 of the 1st embodiment is marked with same tag and omits its explanation.

Other formation and size are identical with the 1st embodiment.

The 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 are to the center line O of the input and output position of the 5th multimode lightguide 22 and the 1st smooth input and output member 12 interval to the input and output center of the 4th multimode lightguide 4: D ₄=5.15 μ m

The 2nd smooth input and output member 14 and the 3rd smooth input and output member 16 to the centreline space of the input and output position of the 5th multimode lightguide 22 every 1/2:D ₅=5.15 μ m

The superfluous loss of the optical waveguide of the optical system that comprises optical waveguide 10 of comparative example is as follows:

From the 2nd smooth input and output member to the 1 smooth input and output member (wavelength 1.49 μ m) :-0.9dB

(light filter is provided with the influence of the position deviation of member)

It is littler than the influence of the embodiment of record in the patent documentation 2 that light filter in the optical system that comprises optical waveguide of the present invention is provided with the influence of position deviation of member, therefore, the optical multiplexer/demultiplexer of the comparable prior art of optical system that comprises optical waveguide of the present invention is simply with low manufacturing cost manufacturing.Light filter is provided with the influence of the position deviation of member, as shown in figure 14, represents side-play amount (μ m) from the design attitude of light filter at transverse axis, represents light loss recruitment (dB) at vertical pivot.Curve A is represented the present invention's the 1st embodiment, and curve B is represented the value of the embodiment of patent documentation 3.

Four suitable examples of optical system of the present invention then, are described.In the following description, as illustration, the suitable example that comprises the 1st embodiment optical system is described.

At first, with reference to Figure 15, the image intensifer that is suitable for example as the 1st of optical system of the present invention is described.Figure 15 is the summary vertical view that comprises the image intensifer of optical system of the present invention.

Image intensifer 600 has two substrates 606,608 that comprise optical system 602,604 of the present invention respectively.The 2nd smooth input and output member 14 of the 1st optical system 602 and the 2nd smooth input and output member 14 of the 2nd optical system 604 connect by fiber amplifier 610 between it.Fiber amplifier 610 is Er-doped fibers of length 1m for example.In addition, the 3rd of the 1st optical system 602 the smooth input and output member 16 is connected with starting of oscillation laser diode 612.The light filter that light filter 24 selections of the 1st optical system 602 make the 1st wavelength transmission and the 2nd wavelength is reflected.

In the image intensifer 600 that so constitutes, in the 1st optical system 602, from the 1st smooth input and output member 12 incidents the 1st wavelength light, and from laser diode 612 when the 3rd smooth input and output member 16 incidents the 2nd wavelength light, these are also photosynthetic, and from the 2nd smooth input and output member 14 outgoing.Emergent light is amplified by fiber amplifier 610.The light that has amplified incides the 2nd smooth input and output member 14 in the 2nd optical system 604 after, separated, for example, make the 1st wavelength light of having amplified from the 1st smooth input and output member 12 outgoing.

Then, with reference to Figure 16, CWDM (rarefaction wave divides multiplexing (Coarse Wavelength Division the Multiplexing)) receiver that is suitable for example as second of optical system of the present invention is described.Figure 16 is the summary vertical view that comprises the CWDM of optical system with receiver of the present invention.

CWDM comprises six optical system 622a～622f with receiver 620.Have, the light filter 24 of the 4th～the 6th optical system 622d～622f is catoptrons again, so omitted the 1st smooth input and output member.The 3rd smooth input and output member 16 of the 1st～the 3rd optical system 622a～622c is connected respectively to the 2nd smooth input and output member of the 4th～the 6th optical system 622d～622f, and the 3rd smooth input and output member 16 of the 4th and the 5th

optical system

622d, 622e is connected respectively to the 2nd smooth input and output member 14 of the 2nd and the 3rd optical system 622b, 622c.The light filter 24 of the 1st optical system 622a makes the 1st wavelength light transmission, and the 2nd～the 4th wavelength light reflected, the light filter 24 of the 2nd optical system 622b makes the 2nd wavelength light transmission, and the 3rd and the 4th wavelength light reflected, the light filter 24 of the 3rd optical system 622c makes the 3rd wavelength light transmission, and the 4th wavelength light is reflected.

Use in the receiver 620 at the CWDM that so constitutes, when the 2nd smooth input and output member 14 from the 1st optical system 622a makes the 1st～the 4th wavelength light incident, from the 1st smooth input and output member 12 difference outgoing the 1st～the 3rd wavelength light of the 1st～the 3rd optical system 622a～622c, from the 3rd smooth input and output member 16 outgoing the 4th wavelength light of the 6th optical system 622f.

Use the suitable example of receiver same with optical system of the present invention being used for CWDM, optical system of the present invention can be applicable to that DWDM ((condensation wave divides multiplexing) Dense Wavelength DivisionMultiplexing) uses receiver.

Then, with reference to Figure 17, the summary vertical view that is suitable for the chiasma type optical multiplexer/demultiplexer of example as the 3rd of optical system of the present invention is described.Figure 17 is the summary vertical view that comprises the chiasma type optical multiplexer/demultiplexer of optical system of the present invention.

Chiasma type optical multiplexer/demultiplexer 640 has the structure of adding the 4th smooth input and output member 642 in the 4th multimode lightguide 20 of optical system 10 of the present invention.

In the chiasma type optical multiplexer/demultiplexer 640 that so constitutes, for example, light was propagated between the 4th smooth input and output member 642 and the 3rd smooth input and output member 16, light is propagated between the 4th smooth input and output member 642 and the 1st smooth input and output member 12.

Then, with reference to Figure 18, the summary vertical view that is suitable for the cross bar switch of example as the 4th of optical system of the present invention is described.Figure 18 is the summary vertical view that comprises the cross bar switch of optical system of the present invention.

Constituting of cross bar switch 660: make the light filter 24 of described chiasma type optical multiplexer/demultiplexer 640 become catoptron 662, and make catoptron 662 can the reflection position 662a between the 4th multimode lightguide and the 5th optical waveguide and with its away from transmission position 662b between move.

In the cross bar switch 660 that so constitutes, for example, when catoptron 662 is positioned at reflection position 662a, light is being propagated between the 1st smooth input and output member 12 and the 4th smooth input and output member 642 and between the 2nd smooth input and output member 14 and the 3rd smooth input and output member 16, when catoptron 662 was positioned at transmission position 662b, light was being propagated between the 1st smooth input and output member 12 and the 2nd smooth input and output member 14 and between the 3rd smooth input and output member 16 and the 4th smooth input and output member 642.

Description of drawings

Fig. 1 is the optics key diagram of the 1st embodiment of the optical system that comprises optical waveguide of the present invention.

Fig. 2 is the optics key diagram of the 2nd embodiment of the optical system that comprises optical waveguide of the present invention.

Fig. 3 is the optics key diagram of the 3rd embodiment of the optical system that comprises optical waveguide of the present invention.

Fig. 4 is the optics key diagram of the 4th embodiment of the optical system that comprises optical waveguide of the present invention.

Fig. 5 is the optics key diagram of the 5th embodiment of the optical system that comprises optical waveguide of the present invention.

Fig. 6 is the optics key diagram of the 6th embodiment of the optical system that comprises optical waveguide of the present invention.

Fig. 7 is the optics key diagram of the 7th embodiment of the optical system that comprises optical waveguide of the present invention.

Fig. 8 is used to represent the optics key diagram that comprises the Design for optical system order of optical waveguide of the present invention.

Fig. 9 is used to represent the optics key diagram that comprises the Design for optical system order of optical waveguide of the present invention.

Figure 10 is used to represent the optics key diagram that comprises the Design for optical system order of optical waveguide of the present invention.

Figure 11 is used to represent the optics key diagram that comprises the Design for optical system order of optical waveguide of the present invention.

Figure 12 is used to represent the optics key diagram that comprises the Design for optical system order of optical waveguide of the present invention.

Figure 13 is the optics key diagram of optical system that comprises the optical waveguide of comparative example.

Figure 14 is the curve map of influence that the expression light filter is provided with the position deviation of member.

Figure 15 is expression is suitable for the image intensifer of example as the 1st of an optical system of the present invention summary vertical view.

Figure 16 is that expression is suitable for the summary vertical view of the CWDM of example with receiver as the 2nd of optical system of the present invention.

Figure 17 is expression is suitable for the chiasma type optical multiplexer/demultiplexer of example as the 3rd of an optical system of the present invention summary vertical view.

Figure 18 is expression is suitable for the photoswitch of example as the 4th of an optical system of the present invention summary vertical view.

Figure 19 is the optical principle key diagram of the optical multiplexer/demultiplexer of record in the patent documentation 1.

Figure 20 is the stereoptics key diagram of the optical multiplexer/demultiplexer of record in the patent documentation 3.

Figure 21 is the optical principle key diagram of the optical multiplexer/demultiplexer of record in the patent documentation 3.

Figure 22 is the job description figure of the optical multiplexer/demultiplexer of record in the patent documentation 3.

Among the figure:

Optical system 12-the 1st smooth input and output member of 10-the 1st embodiment

14-the 2nd smooth input and output member 16-the 3rd smooth input and output member

20-the 4th multimode lightguide 22-the 5th multimode lightguide

24-light filter 26-light filter is provided with member

The optical system of optical system 210-the 3rd embodiment of 110-the 2nd embodiment

The optical system of optical system 320-the 5th embodiment of 310-the 4th embodiment

The optical system of optical system 340-the 7th embodiment of 330-the 6th embodiment

The optical system of 360-comparative example

Claims

1. optical system that comprises optical waveguide is characterized in that:

Has the the 1st, the 2nd and the 3rd smooth input and output member and can be with the 4th and the 5th multimode lightguide of multimode propagation light, between the described the 4th and the 5th multimode lightguide, have with the described the 4th and the 5th multimode lightguide in the direct of travel of light the light filter that light filter uses is set crossingly member is set, what the described the 1st smooth input and output member was connected to described the 4th multimode lightguide is provided with the end face of the opposite side of member with described light filter, and what the described the 2nd and the 3rd smooth input and output member was connected to described the 5th multimode lightguide is provided with the end face of the opposite side of member with described light filter;

The the described the 4th and the 5th multimode lightguide different with the width on the direction of the direct of travel quadrature of light, perhaps, the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every 1/2 different to the interval of the input and output center of described the 4th multimode lightguide to the center line of the input and output position of described the 5th multimode lightguide with the 1st smooth input and output member with the 2nd and the 3rd smooth input and output member.

2. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

Described the 4th multimode lightguide with the direction of the direct of travel quadrature of light on width than described the 5th multimode lightguide with the direction of the direct of travel quadrature of light on width big.

3. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

The multimode lightguide of the light input and output member of the light that one of has connected in the light that will be input in the described the the 1st, the 2nd and the 3rd smooth input and output member with the direction of the direct of travel quadrature of light on width than other multimode lightguide with the direction of the direct of travel quadrature of light on width little.

4. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

Described the 4th multimode lightguide with the direction of the direct of travel quadrature of light on width and described the 5th multimode lightguide with the direction of the direct of travel quadrature of light on width be more than the 5 μ m below the 20 μ m.

5. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

The described the 1st smooth input and output member with the direction of the direct of travel quadrature of light on width and the described the 2nd and the 3rd smooth input and output member with the direction of the direct of travel quadrature of light on width at least one is different.

6. the optical system that comprises optical waveguide according to claim 5 is characterized in that:

The described the 1st smooth input and output member with the direction of the direct of travel quadrature of light on width than the described the 2nd and the 3rd smooth input and output member with the direction of the direct of travel quadrature of light on width at least one is little.

7. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

8. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

The the 2nd and the 3rd smooth input and output member to the centreline space of the input and output position of described the 5th multimode lightguide every the 1/2 to the 2 and the 3rd smooth input and output member big to the center line and the 1st smooth input and output member of the input and output position of described the 5th multimode lightguide to the interval of the input and output center of described the 4th multimode lightguide.

9. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

The center line that extends on center line that extends on the direct of travel of the light of described the 4th multimode lightguide and the direct of travel at the light of described the 5th multimode lightguide departs from.

10. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

The center line and the center line of the 2nd and the 3rd smooth input and output member to the input and output position of described the 5th multimode lightguide that extend on the direct of travel of the light of described the 4th multimode lightguide depart from.

11. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

Described light filter makes the 1st transmitted light and the 2nd transmitted light transmission and the 3rd reflected light is reflected, incide the 2nd smooth input and output member and be suppressed from the 1st transmitted light of the 1st smooth input and output member incident, incide the 3rd smooth input and output member and be suppressed to the 1st and the 2nd smooth input and output member incident from the 3rd reflected light of the 2nd smooth input and output member incident to the 1st and the 3rd smooth input and output member incident;

From the 2nd transmitted light of the 2nd smooth input and output member incident to the 1st smooth input and output member incident and be suppressed to the 2nd and the 3rd smooth input and output member incident.

12. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

Described light filter makes the 1st transmitted light and the 2nd transmitted light transmission and with the reflection of the 3rd reflected light, incides the 2nd light output member and is suppressed to the 1st and the 3rd smooth input and output member incident from the 2nd transmitted light of the 1st smooth input and output member incident;

Incide the 1st smooth input and output member and be suppressed from the 1st transmitted light of the 2nd input and output member incident to the 2nd and the 3rd smooth input and output member incident, from the 3rd reflected light of the 3rd smooth input and output member incident to the 2nd smooth input and output member incident and be suppressed to the 1st and the 3rd smooth input and output member incident.

13. an optical system is characterized in that:

It is a pair of that the optical system of record in the optical system of record and the claim 12 is become, and be coupled by fiber optics ground between the 2nd smooth input and output member.

14. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

Described light filter makes the reflection of the 1st reflected light and the 2nd reflected light and with the 3rd transmitted light transmission, incide the 3rd smooth input and output member and be suppressed from the 2nd reflected light of the 2nd smooth input and output member incident, incide the 1st smooth input and output member and be suppressed to the 2nd and the 3rd smooth input and output member incident from the 3rd transmitted light of the 2nd smooth input and output member incident to the 1st and the 2nd smooth input and output member incident;

15. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

Described light filter makes the reflection of the 1st reflected light and the 2nd reflected light and with the 3rd transmitted light transmission, incides the 2nd light output member and is suppressed to the 1st and the 3rd smooth input and output member incident from the 3rd transmitted light of the 1st smooth input and output member incident;

16. an optical system is characterized in that:

It is a pair of that the optical system of record in the optical system of record and the claim 15 is become, and be coupled by fiber optics ground between the 2nd smooth input and output member.

17. an optical system is characterized in that:

18. an optical system is characterized in that:

It is a pair of that the optical system of record in the optical system of record and the claim 14 is become, and be coupled by fiber optics ground between the 2nd smooth input and output member.

19. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

100μm≤L ₄+L ₅≤800μm

50μm≤L ₄+L ₅≤400μm。

20. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

1st, the 2nd and the 3rd smooth input and output member is monomode optical waveguide.

21. the optical system that comprises optical waveguide according to claim 1 is characterized in that:

The 1st smooth input and output member is an optical fiber, and the 2nd and the 3rd smooth input and output member is monomode optical waveguide.

22. an optical multiplexer/demultiplexer is characterized in that,

In the optical system that comprises optical waveguide according to claim 1, be provided with at described light filter and be provided with light filter on the member.