CN1288464C

CN1288464C - Bulk optical interferometer

Info

Publication number: CN1288464C
Application number: CN 02123139
Authority: CN
Inventors: 曾和平; 梁丰; 吴立; 凌纪武
Original assignee: JDS Uniphase Corp
Current assignee: Flex Products Inc; Lumentum Operations LLC
Priority date: 2002-06-19
Filing date: 2002-06-19
Publication date: 2006-12-06
Anticipated expiration: 2022-06-19
Also published as: CN1464317A

Abstract

The present invention relates to an optical crossed multiplexer based on a Mach-Zehnder interferometer, which can be used as a crossed multiplexer for optical channels of wavelength division multiplexing (WDM) and dense wavelength division multiplexing (DWDM). The optical channel crossed multiplexer/demultiplexer is mixed with WDM and DWDM channel banks for network transmission, and/or WDM and DWDM signals are divided into channel banks of channel spacing, which are more suitable for demultiplexing in the future. The crossed multiplexer of the present invention respectively uses an annular resonator as a phase shifter to provide broad pass bands and cut-off bands for flatheaded wavelength response.

Description

Body formula (BULK) optical interferometer

The mutual reference of related application

This is a first application of the present invention.

Technical field

This invention relates to a kind of optical interdferometer, especially a kind of based on Mach-Zehnder (Mach-Zehnder) interferometer (MZI), intersect multiplexer (interleaver)/separate as wavelength channel and intersect the body formula optical interferometer of multiplexer (de-interleaver).

Background technology

As being applicable to device with first wavelength channel signal at interval and the interface that is applicable between the device with second wavelength channel signal at interval, light intersection multiplexer has become a kind of popular instrument in dense wave division multipurpose (DWDM) communication network.In the past, the 200GHz channel spacing is at interval commonly used, but along with the growth of requirement that increases bandwidth, the 100GHz channel spacing becomes a kind of standard.In follow-on communication network, the channel spacing of 50GHz even 25GHz also will become very usual.But, traditional demultiplexing wave filter, as dichroic filters, if without complexity and improvement high cost, just do not possess with at interval so closely channel separately do not produce the ability of great channel interference.Therefore, light intersect multiplexer be used to interval closely channel separate, make it become two groups of channels, these interchannels be original twice at interval.This process can continue to be separated into up to channel and have sufficient distance to guarantee the multiplexing validity of tradition.

The multiplexer that intersects has a variety of different forms, as: birefringece crystal intersection multiplexer, this intersection multiplexer is illustrated that in the 6th, 301, No. 046 patent of the U.S. of delivering October 9 calendar year 2001 this patent is shown by examining Chou Tai people such as (Kuochou Tai); And for example enjoy disclosed integrated lattice intersection multiplexer in the 5th, 596, No. 661 that profit (CharlesHenry) is shown, that the U.S. delivered on January 21st, 1997 patents by the charles; Shown by Benjamin Ding Geer people such as (Benjamin Dingel) for another example, be published in the U.S. the 6th in October 16 calendar year 2001,304, No. 689 patents and shown, be published in U.S. the 6th, 252 in June 26 calendar year 2001 by thunder letter Pa Yamu (Reza Paiam), No. 716 patents, and Michelson G-T (Michelson Gires-Tournois) interferometer (MGTI) of being shown, be published in the 6th, 169, No. 828 patents of the U.S. in January 2 calendar year 2001 by fourth illiteracy Cao (Simon Cao).Based on polarization and use an a kind of intersection multiplexer of cutting apart the mirror toroidal resonator to be invented by people such as (Gan Zhou) of sweet week, this patent of invention is published in June 5 calendar year 2001 as the 6th, 243, No. 200 patents of the U.S..

An object of the present invention is to overcome the deficiencies in the prior art, and provide a kind of simple body formula light to intersect multiplexer, this intersection multiplexer has negligible amounts, low cost of manufacture and the parts of reliable and stable performance can also be provided.

Summary of the invention

Therefore, the present invention relates to a kind of light intersection multiplexer, comprising:

Be used for launching the first input end mouth of input beam;

Be used for input beam is divided into respectively first beam splitter through first and second beamlet of first and second light paths;

Be positioned at first toroidal resonator of first light path, this resonator comprises at least two surface and the first's reflectings surface that belong to total reflection substantially, first's reflecting surface is injected first toroidal resonator with the part of first beamlet, and remaining first beamlet is reflected away, like this, light from first toroidal resonator mixes with remaining first beamlet, and formation first is the blend sub light beam again;

Be positioned at second toroidal resonator of second light path, this resonator comprises at least two surface and the second portion reflectings surface that belong to total reflection substantially, the second portion reflecting surface is injected second toroidal resonator with second a beamlet part, and remaining second beamlet is reflected away, like this, light from second toroidal resonator mixes with remaining second beamlet, and formation second is the blend sub light beam again;

Second beam splitter is used for receiving the first and second blend sub light beams again, thereby causes first and second interference of blend sub light beam again, and produces first and second output beams;

Be used for exporting first output port of first output beam; And

Be used for exporting second output port of second output beam.

Another aspect of the present invention relates to the Mach-Zehnder interferometer, comprising:

Beam splitter is used for input beam is separated into first and second beamlets, and interferes arm and second to interfere directed first and second beamlets of arm along first of interferometer respectively;

Be positioned at first toroidal resonator that interferometer first is interfered arm, had the first resonance delay of the phase response that influences first beamlet;

Be positioned at second toroidal resonator that interferometer second is interfered arm, had the second resonance delay of the phase response that influences second beamlet;

Be used for interfering first and second beamlets to form the light beam mixer of first and second output beams.

Description of drawings

In conjunction with the accompanying drawing that preferred embodiment is shown, will be described in detail this invention, wherein:

Fig. 1 is the synoptic diagram according to an embodiment of the interferometer of this invention;

Fig. 2 is the synoptic diagram according to another embodiment of the interferometer of this invention;

Fig. 3 a and 3b illustrate the optional example of the toroidal resonator of the embodiment that can be used for Fig. 1 and Fig. 2;

Fig. 4 is the transmission spectrum synoptic diagram of two groups of channels in the light intersection multiplexer according to an embodiment of the invention;

Fig. 5 is that according to another embodiment of the invention light intersects the transmission spectrum synoptic diagram of two groups of channels in the multiplexer;

Fig. 6 is about the phase differential of one group of channel and the curve map of the relation between the wavelength in the light intersection multiplexer according to an embodiment of the invention,

Embodiment

Intersection multiplexer 10 according to the present invention wherein can be injected light beam or penetrate the above-mentioned interference instrument by the one or more ports in four

port ones

1,12,13 and 14 based on Mach-Zehnder interferometer (MII).Each port comprises collimation/condenser lens 16, and these lens are optically coupled to the lasso 17 that is wrapping fibre-optic waveguide 18 1 ends.In our discussion, for convenience and for the purpose of simple and direct, we suppose that light is launched to enter by first port one 1 intersects multiplexer 10 and respectively by 2,13 outputs of the second and the 3rd port one.But, it will be appreciated by those skilled in the art that other feasible combination in addition, comprising: respectively by the second and/or the 3rd port one 2 and 13 inputs, more respectively by the first and/or the 4th port one 1 and 14 outputs.

Typical input beam 20 is dense wave division multipurpose (DWDM) signals, this signal comprises many wavelength channels, light beam 20 is launched by first port one 1, and had first light beam and cut apart the beam splitter of coating 23a form and be divided into first beamlet 21 and second beamlet 22, wherein cut apart on the part that coating 23a is painted on first glass (or other transparency) substrate, one side.First light beam is cut apart coating 23a and preferably input beam 20 is divided into two, and just reflectivity range is at 42% to 50%, and desirable reflectivity is 50%.First beamlet 21 by first substrate 24 till the first's reflecting surface 26 with the opposite side that is placed on first substrate 24 intersects.The reflectivity of first's reflecting surface 26 is preferably in 42% to 50%.The part of first beamlet 21 is by first toroidal resonator 27, and this resonator comprises a mirror 31 and another mirror 32.After the delay distance through first resonator cavity, light comes out and mixes from the light of first's reflective coating 26 reflection from first ring resonator 27, forms the first blend sub light beam 33 again.First again blend sub light beam 33 directly imported first substrate 24.

Second beamlet 22 is cut apart coating 23a reflection by first light beam during by second glass (or other transparency) substrate 34, so as with the intersection of second portion reflecting surface.The reflectivity of second portion reflecting surface 36 is preferably in 2.4% to 5.2%.The part of second beamlet 22 is by comprising second toroidal resonator 37 of first mirror 41 and second mirror 42.Through the light behind the second annular delay distance from 37 outgoing of second toroidal resonator, and and mixed by the light of second portion reflecting surface 36 reflection, directive first substrate 24 has so just formed the second blend sub light beam 38 again.Second again blend sub light beam 38 on the second light beam dividing layer 23b with first again blend sub light beam 33 interfere, form the light of a part, i.e. first output beam and the remaining light of second port one, 2 outputs, i.e. second output beam of the 3rd port one 3 outputs.Preferably also between 43% to 50%, desirable reflectivity is 50% to the reflectivity range of the second light beam dividing layer 23b.Produce simply in order to make, first and second light beams are cut apart coating 23a can have identical reflectivity 50% with 23b, and is coated simultaneously.

Cut apart coating 23a from first and return first light path that second light path of cutting apart coating 23b is called as the Mach-Zehnder interferometer to first's reflecting surface 26.Cut apart coating 23a from first and return second light path that second light path of cutting apart coating 23b is called as the Mach-Zehnder interferometer to second portion reflecting surface 36.In order to cause interference, first light path is different with the length of second light path.This length difference is known as optical path difference.When using as the intersection multiplexer, the light path that preferably has the partial reflection surface is that second light path is all lacked than other light path, and the reflectivity on this partial reflection surface is lower, moreover the length difference of first light path and second light path is the first resonator delay distance half, supposes that the delay distance of first and second resonators equates.When intersecting multiplexer, one group of wavelength channel, for example International Telecommunication Union's channel of even number is exported by port one 2, and another group wavelength channel for example odd number ITU channel exported by port one 3.

Fig. 2 is according to the synoptic diagram of an embodiment of this invention, has wherein used minimum substrate material.New first and

second substrates

124 and 134 are respectively than its counterpart 24 among Fig. 1 and 34 much thin.Therefore, need the 3rd substrate 144 and support first's reflectance coating 26.Substrate 124 also can be divided into two independently substrates, and each sheet all has the one deck among light beam dividing layer 23a and the 23b.

Fig. 3 a and 3b are the exemplary plot of two toroidal resonators in addition that replaces first and second toroidal resonators 27 and 37.(Fig. 3 a) comprises second substrate 34, second portion reflectance coating 36 and three reflecting surfaces 141,142,143 to toroidal resonator 137.It will be appreciated by those skilled in the art that and to use any amount of reflecting surface.Fig. 3 b is second toroidal resonator 37 that has an angle of wedge shape adjustment sheet 150.The adjustment sheet 150 that refraction coefficient is different from air can be used for regulating by a small margin the optical path distance of one of them toroidal resonator with two toroidal resonators of suitable coupling.Accurately regulate wedge shape adjustment sheet 150 and can produce more or less light beam by himself, thus lengthening or shorten the optical path length of toroidal resonator.

Fig. 4 and Fig. 5 illustrate the theoretic transmission spectrum response of intersection multiplexer according to the present invention.Solid line is represented even number ITU wavelength channel, and dotted line is then represented odd number ITU wavelength channel.Have-bandwidth of the passband of 0.5dB loss accounts for and intersects more than 85% of multiplexer Free Spectral Range (FSR), have-bandwidth of cutting band of 25dB loss surpassed and intersected 75% of multiplexer FSR.Not being both of two bar response curves because first and second partial reflections surfaces 26 reflectivity different with 36 cause.In order to obtain curve map as shown in Figure 4, the reflectivity that the reflectivity that first and second light beams are cut apart coating 23a and 23b should be respectively 50% and 48.3%, the first and second

partial reflection coating

26 and 36 then is respectively 44.8% and 3.4%.In order to obtain curve map as shown in Figure 5, the reflectivity that the reflectivity that first and second light beams are cut apart coating 23a and 23b all should be 50%, the first and second

partial reflection coating

26 and 36 then respectively 42.2% and 3.3%.

Diagram shows shown in Figure 6 according to the phase differential of the odd number ITU wavelength channel of intersection multiplexer of the present invention.Intersect on the continuous wavelength channel of FSR of multiplexer being equivalent to light, phase differential 0 and ± replace between the π.The horizontal loop line segment that has 0 phase differential among the figure is represented the constructive interference part, i.e. tack (flattop) passband, have ± the horizontal loop line segment of π phase differential then represents the destructive interference part, promptly cuts band.

Also can be used for separating the wavelength channel of the multiplexing two groups of complementations of intersection according to the equipment of this invention.Each bundle in the two bundle input beams comprises the wavelength channel of one group of complementation wherein, this two light beams is transfused to the second and the 3rd port one 2 and 13 (or the first and the 4th port one 1 and 14) respectively, and being imported into beam splitter, this two-beam interferes in beam splitter and is divided into two beamlets.Every beamlet arrives in the

toroidal resonator

27 or 37, and form two blend sub light beams again, these two the blend sub light beam is mixed again in beam splitter again, and from the first or the 4th port one 1 or 14 outputs (perhaps from the second or the 3rd port one 2 or 13 outputs).

Claims

1. optical interdferometer device comprises:

Be used for launching the first input end mouth of input beam;

Be positioned at first toroidal resonator of first light path, this resonator comprises at least two surface and the first's reflectings surface that belong to total reflection substantially, first's reflecting surface is injected first toroidal resonator with the part of first beamlet, and remaining first beamlet is reflected away, like this, the light that postpones through first resonance from first toroidal resonator mixes with remaining first beamlet, and formation first is the blend sub light beam again;

Be positioned at second toroidal resonator of second light path, this resonator comprises at least two surface and the second portion reflectings surface that belong to total reflection substantially, the second portion reflecting surface is injected second toroidal resonator with second a beamlet part, and remaining second beamlet is reflected away, like this, the light that postpones through second resonance from second toroidal resonator mixes with remaining second beamlet, and formation second is the blend sub light beam again;

Be used for exporting first output port of first output beam; And

Be used for exporting second output port of second output beam.

2. device according to claim 1, wherein first beam splitter comprises that lip-deep first light beam of the substrate that is coated in substantial transparent cuts apart coating, this reflectivity range of cutting apart coating is between 43% to 50%.

3. device according to claim 2, wherein second beam splitter comprises that being coated in lip-deep second of substrate of cutting apart the adjacent substantial transparent of coating with first light beam cuts apart coating, this reflectivity range of cutting apart coating is between 43% to 50%.

4. device according to claim 3, wherein first's reflectance coating is painted on another surface of substrate of substantial transparent.

5. device according to claim 1, wherein first optical path length is meant from first beam splitter and returns the distance of second beam splitter to first toroidal resonator; Second optical path length is meant from first beam splitter and returns the distance of second beam splitter to second toroidal resonator; Wherein first resonance postpones to postpone to equate with second resonance; First optical path length has more half the distance that is equivalent to that first resonance postpones than second optical path length.

6. device according to claim 5, wherein the reflectivity of first's reflectance coating is between 42% to 50%.

7. device according to claim 6, wherein the reflectivity of second portion reflectance coating is between 2.4% to 5.2%.

8. device according to claim 1, wherein first toroidal resonator also comprises the adjustment sheet that is used for regulating optical path length.

9. device according to claim 7, wherein input beam comprises a plurality of wavelength division multiplexed channels; First output beam comprises first group of channel of described a plurality of channels, and second output beam comprises second group of channel of described a plurality of channels.

10. device according to claim 9, wherein first group of channel comprises one or more odd number ITU channels; Second group of channel comprises one or more even number ITU channels.

11. a Mach-Zehnder interferometer comprises:

Beam splitter is used for a branch of input beam is separated into first and second beamlets, and interferes arm and second to interfere directed first and second beamlets of arm along first of interferometer respectively;

12. device according to claim 11, wherein first toroidal resonator also comprises the adjustment sheet that is used for regulating optical path length.

13. device according to claim 11, wherein first resonance postpones to postpone to equate basically with second resonance, and first length of interfering arm has more than the length of the second interference arm and is equivalent to first half the distance of delay that resonates.

14. device according to claim 13, wherein input beam comprises a plurality of wavelength division multiplexed channels, and first output beam comprises first group of channel of described a plurality of channels, and second output beam comprises second group of channel of described a plurality of channels.

15. device according to claim 13, wherein first group of channel comprises one or more odd number ITU channels, and second group of channel comprises one or more even number ITU channels.