CN101038356A - Optical power monitor - Google Patents
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- CN101038356A CN101038356A CNA2007100881305A CN200710088130A CN101038356A CN 101038356 A CN101038356 A CN 101038356A CN A2007100881305 A CNA2007100881305 A CN A2007100881305A CN 200710088130 A CN200710088130 A CN 200710088130A CN 101038356 A CN101038356 A CN 101038356A
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Abstract
An optical power monitor capable of being reduced in size even when designed as a multi-channel monitor, and having a reduced light transmission loss is disclosed. The optical power monitor has two optical fibers provided on the light transmission upstream and downstream sides and having cores, the end surfaces which are opposed to each other with the core optical axes offset from each other, and which are fusion-spliced to each other in a fusion splicing portion, a light reflection surface which faces a portion of the upstream-side optical fiber core end surface offset to protrude from the downstream-side optical fiber core end surface in the fusion splicing portion, and which is provided in the downstream-side optical fiber cladding layer, and a photo-diode positioned opposite from the light reflection surface with respect to the downstream-side optical fiber core. Third-order or fourth-order lights strengthening each other in lights leaked into the downstream-side optical fiber cladding layer from the upstream-side optical fiber core end surface are reflected by the reflection surface provided in the cladding layer and detected with the photo-diode.
Description
Technical field
The present invention relates to mainly be used in the optical power monitor in the optical communication field.
Background technology
In recent years, noticeable technological change having taken place aspect information communication, carries out the transition to optical signal communications from electrical signal communication and can satisfy the requirement that improves communication speed and deal with the quantity of information increase that causes along with the prosperity of the Internet.Information from a plurality of relay points concentrates on many trunk cables.Therefore, with regard to processing power and speed, it is favourable replacing the conventional rail cable with optical cable.Restudy communicating by letter between optical cable and the user terminal and begin, and realize that at lower cost the requirement of more comfortable information environment is urgent day by day.
Along with the realization of optical-fiber network, made the high speed information exchange become possibility, and, the new purposes of optical-fiber network is expanded.Correspondingly, the quantity of information that sends by optical-fiber network constantly increases.Be fit to the quantity of information that optical cable is handled in order to increase, use utilizes high-frequency signal to improve the technology of the semaphore of unit interval, or be called the technology of wavelength multiplexing system, that is, send the technology of signal simultaneously for different items of information by an optical fiber with a plurality of wavelength.Form compact and communication network requirement highly reliably guarantees to be connected with mulitpath and to utilize many optical cables in many directions.From the viewpoint of safeguarding, utilize many optical cables indispensable.
In order to form the optical communication circuit that sends a plurality of signals by optical cable, need wavelength-division multiplex (hereinafter being abbreviated as WDM) system, in wdm system, the wavelength multiplexing light signal is divided into the signal of different wave length; Multiplexed wavelength optical signals; And extraction and the insertion of carrying out light signal.Along with the increase of quantity of information, the importance of management information has also increased.For losing of light signal, the place that must discern light signal at once and lose.Also must check signal intensity, and whether the connection of light signal exists.If transmission range increases, then light signal strength is only reducing by meeting during the Optical Fiber Transmission.Therefore, the Erbium-Doped Fiber Amplifier (EDFA) (hereinafter being abbreviated as EDFA, erbium doped fiber amplifier) that needs amplifying optical signals.Utilize EDFA to measure the intensity of the outside light signal of supplying and the intensity that amplification sends to extraneous light signal afterwards, with definite amplification ratio.In order to make up optical communication system highly reliably, it is indispensable being equipped with function for monitoring in each optical transmission circuit part.
For monitoring light signals, people's use is extracted a part of light signal by photo-coupler and is detected by extracting the method for the light signal that takes out by the photodiode that is connected with optical fiber.This method requires welding to connect each parts, and this has hindered the minimizing of installation steps numbers.Photo-coupler has therein to press close to mutually so that enable the structure of the extraction of light signal as the optical signal transmission fibre core partly of optical fiber.The length of the core segment of pressing close to mutually is the important parameter of extraction amount.Therefore, be difficult to dwindle the size of product.Especially in up-to-date design, multiplexed number of wavelengths to be increased so that increase the quantity of information that can once send.Because input carries out after demultiplexing becomes wavelength, the quantity of the optical power monitor that unit is required has increased.Owing to the spatial accommodation that can distribute to optical power monitor in the unit is limited, necessarily require to dwindle the size of each power monitor.
For example, United States Patent (USP) the 6th, 603, the optical power monitor that discloses minification No. 906.Figure 17 B shows the structure of disclosed optical power monitor.Figure 17 A shows the example with the optical power monitor assembly 71 that is installed in a plurality of optical power monitors 70 in the box 69 of removing upper box cover.Figure 17 B is the skiagraph of optical power monitor 70.With reference to Figure 17 A and 17B, have the thin glass of crinosity packet header 53 of two optical fiber 51 and 52 and graded index (GRIN, gradient index) lens 54 toward each other, between them, form pre-fixed gap 55.On the end face of grin lens 54, form wave filter 56.The light of grin lens 54 is passed in wave filter 56 reflections or transmission.Light by grin lens 54 transmissions passes space 57 and converts electric signal to by photon detector or photodiode 58, so that take out by terminal 59.Electricity output by from photon detector 58 can obtain the light intensity in the light path.The thin glass of crinosity packet header 53 and grin lens 54 are by glass tube 60 and 60 ' location.To be its refractive index begin along continually varying glass cylinder radially outward from its central shaft grin lens.If light is to external diffusion, then the direction of light ray propagation is folded to central shaft.
Referring now to Figure 17 B light stream is described.The light (input light) that enters space 55 from optical fiber 51 passes the wave filter 56 that grin lens 54 arrives on the grin lens end face.The most of light that arrive wave filter 56 are reflected, and pass grin lens 54 and go forward side by side into optical fiber 52 in space 55, become output light.Light by wave filter 56 transmissions passes space 57, enters photon detector 58 and converts electric signal to, by terminal 59 outputs.This light path is represented with solid arrow.On the contrary, when by optical fiber 52 input light, light takes out light (output light) via the propagated similar to above-mentioned light path and from optical fiber 51.This light path with dashed lines arrow is represented.Used the title of in the instructions of U.S. patent documents, quoting in this description.In instructions of the present invention, photon detector is called as photodiode.
In the optical power monitor shown in Figure 17 B 70, light emission (radiation) in the air at least once.Because air has the refractive index different with optical fiber, is radiated airborne light generation scattering.Is that to collect scattered light requisite with the grin lens by the lens of representative.Therefore, the product size of optical power monitor depends on the size of grin lens and glass tube.Therefore, be difficult to dwindle the overall dimensions of the optical power monitor assembly 71 shown in Figure 17 A.
Openly Jap.P. discloses the optical power monitor that utilizes waveguide 2003-329862 number.The planimetric map of the optical waveguide module that Figure 18 A is made up of optical power monitor.Figure 18 B is the sectional drawing of explanation with the principle of optical power monitor measuring light energy.In substrate 81, form many waveguides 90 that are parallel to each other usually.The passage 83 that extends along the direction vertical with waveguide 90 is divided into input side part 86 and outgoing side part 87 with waveguide 90.Reflective filter 84 is inserted in the passage 83, and photoelectric detector 85 is placed on 86 these lateral reflection wave filters 84 of importation.Therefore, form the optical circuit 80 of planar waveguide-type.The situation of utilizing measurement of luminous flux luminous energy is described referring now to the sectional drawing of Figure 18 B.Waveguide 90 has top covering 91 and under-clad layer 93, and fibre core 92 places between the two.In the air of the light emission of propagating via fibre core 92 in the passage 83.Most of light pass in the fibre core 92 that reflective filter 84 enters outgoing side 87.Part light (dotting) wave filter 84 reflection that is reflected enters in the photoelectric detector 85.This part light is converted into electric signal.Can measure the light intensity in the light path in this way.
Self-evident, in the disclosed planar waveguide-type optical circuit 80 of above-mentioned Japanese document, hold the thickness of substrate of waveguide and the mechanism etc. that holds photodiode and hindered dwindling of size.In addition, well-known, the light loss in the part of connection waveguide and optical fiber is bigger.Be difficult to reduce the wastage.As the means that reduce the wastage, what expect easily is, replaces optical waveguide in the disclosed technology of above-mentioned Japanese document with optical fiber.Even replacing with optical fiber under the situation of optical waveguide, the same with the disclosed planar waveguide-type optical circuit of above-mentioned Japanese document 80, the light that enters from input side also is transmitted into the air once.Resolve into the light that propagates into outgoing side and the light that enters photoelectric detector owing to be transmitted into the airborne light wave filter that is reflected, so be difficult to reduce light loss.
Even for being considered to the low disclosed optical power monitor 70 of above-mentioned U.S. patent documents that decreases monitor, it is believed that, as long as this assembly uses optical fiber pigtail, grin lens and photoelectric detector separately, the limit of dwindling single channel optical power monitor 70 sizes is diameter 3.0mm * 20mm.Shown in Figure 17 A, arrange for multichannel, parts are contained in the box 69, thereby product size is further increased, and be difficult to dwindle overall dimensions.
Summary of the invention
The objective of the invention is, even provide a kind of the depositing also can minification and reduce the optical power monitor of optical transmission loss at multichannel cloth.
Have according to optical power monitor of the present invention: two optical fiber, every optical fiber has fibre core that is in its center and the covering that centers on fibre core, article two, optical fiber is in the upstream side and the downstream of light transmission path respectively, and their end face weld mutually in the face of and be fused, their fibre core optical axis is offset mutually; Be arranged on the light reflection surface in the covering of downstream optical fiber, described light reflection surface is towards in the weld skew and from the part end face of the outstanding upstream side fiber core of the end face of downstream fiber core, and with the fibre core optical axis of downstream optical fiber at an angle; And photodiode, be oppositely arranged with respect to downstream fiber core and described light reflection surface.Described photodiode detects by the transmission of upstream side fiber core, from skew and the light that reflects to the covering of downstream optical fiber and by described light reflection surface from the part face leakage of the outstanding upstream side fiber core of the end face of downstream fiber core.Described light reflection surface is arranged in from the part face leakage of upstream side fiber core to position that the light of the covering of downstream optical fiber is interfered mutually and strengthened.
Best, described light reflection surface is arranged in from the part face leakage of upstream side fiber core to the 3rd or the 4th position that the light of the covering of downstream optical fiber is interfered mutually and strengthened.
Every optical fiber is made up of the covering around fibre core that is positioned at fiber optic hub and the covering fibre core.And have the fibre core of big refractive index and have the corresponding fibre core side face in border between the covering of less refractive index and make light total reflection, only in fibre core, transmit to guarantee light by the fiber core transmission.If the end face of two optical fiber of welding is arranged to several microns with the skew between the optical axis of fiber core simultaneously mutually, then the connection between connection between the fibre core end face and the covering end face occupies most of weld.By the connection between the fibre core end face, make light be transferred to the downstream fiber core from the upstream side fiber core.On the other hand, a part of fibre core end face by upstream side optical fiber is connected with welding between the covering end face of downstream optical fiber, makes by arriving the leakage of light on welding surface in the downstream fibre cladding relative with the upstream side fiber core after the transmission of upstream side fiber core.The light that leaks is propagated forward without barrier.But, because fibre core and covering there are differences on refractive index, and owing to have crescent-shaped with the fibre core end face part of covering end face welding, by the light of a part of welding fibre core face leakage in the covering end face in covering along radial expansion.Light along radial expansion in covering transmits in covering, simultaneously by the side face repeated reflection of covering.Therefore, between the transmission period in covering, thereby the light of transmission and reflection is interfered reinforcement mutually mutually or is weakened.The light of repeated reflection transmission is provided in the covering and towards the light reflection surface reflection of fibre core end face part in covering.Therefore the direction of light ray propagation changes, and makes light radiation outside optical fiber.If photodiode is arranged on the optical propagation direction extended line of the light ray propagation that light reflection surface reflects, then photodiode just becomes electric current with transform light energy, thereby obtains the electric signal that is directly proportional with luminous energy.
Light transmission upstream side fiber core end face and light transmission downstream fiber core end face interconnect, and are offset several microns mutually simultaneously.Therefore, see over, in the fiber core coupling part, look like crescent-shaped from the outstanding part upstream side fibre core section part of downstream fibre core from the light transmission downstream.The breadth extreme of described crescent-shaped is corresponding to side-play amount.Under connected state before the welding, the shape of weld is such in vertical section, and the fibre core end face is vertical with the central shaft of optical fiber usually, and vertical end face is offset several microns mutually usually.When the heating optical fiber end face made their mutual weldings, the fibre core end face was welded together mutually, and there is to a certain degree bending in the corner of fibre core end face because of surface tension.Also there is bending to a certain degree in the corner of covering end face.
The face of weld of fibre core has the crescent-shaped that has bending in the optical fiber vertical section.Come out to enter and plane from the fibre core end face with bending, promptly, light in the parallel downstream covering of offset plane (plane that comprises upstream side fibre core optical axis and downstream fibre core optical axis) has different angles because of the bending of the fibre core end face that welding causes with respect to the fibre core optical axis, thereby makes the light that reflects in covering interfere mutually to strengthen mutually or weaken.Best, three rank or quadravalence light that light reflection surface reflection is strengthened mutually, and with the light of photodiode detection of reflected.Therefore, importantly, above-mentioned part upstream side fiber core end face is relative with light reflection surface at a predetermined angle.In other words, in the vertical section vertical with offset plane, weld is vertical with the optical axis of fiber core, and light reflection surface is also vertical with optical axis.Therefore, above-mentioned part upstream side fibre core end face and light reflection surface are parallel to each other.In offset plane, welding fibre core end face and light reflection surface respectively with the optical fiber transversal section at an angle.Therefore, above-mentioned part fibre core end face in the weld and light reflection surface are at a predetermined angle toward each other.On the other hand, in the plane vertical, propagate symmetrically with respect to the optical fiber offset plane, reflected by the covering side face from the light that above-mentioned part upstream side fibre core end face comes out with offset plane.Therefore, these light are not interfered mutually.
Experimental results show that, in offset plane, weld curvature is minimum around upstream side fibre core end face, that is to say, the radius-of-curvature maximum, on the contrary, the weld curvature in the offset plane around the fibre core end face of downstream with upstream side fibre core end face position adjacent on maximum, that is to say the radius-of-curvature minimum.In addition, made relation between weld curvature and the light emergence angle by experiment clear.At peripheral part of upstream side fibre core end face, light is 5 ° to 15 ° with respect to the emergence angle θ u of fibre core optical axis.With adjacent part upstream side fibre core end face around the fibre core end face of downstream on, light emergence angle θ d is 2 ° to 12 °.On the fiber core end face of the mutual welding in skew ground mutually, θ u is greater than θ d, and the difference of θ u and θ d is about 3 ° to about 6 °.The light emergence angle changes with the position of weld.Therefore, from and upstream side fibre core end face around approaching position cycle of being radiated the light repeated reflection in covering the covering with from and cycle of downstream fibre core end face light repeated reflection covering of approaching part upstream side fibre core end face radiation on every side between there are differences.Therefore, these light are interfered mutually, periodically strengthen mutually and weakening on some position.If the position that light is strengthened for the first time mutually is the single order position, then by on three rank or quadravalence add strong position and be equipped with light reflection surface, the light can on light reflection surface, being collected in to maximal efficiency in the weld from upstream side fibre core face leakage to the downstream fibre cladding.
Optical power monitor of the present invention can be equipped to optical fiber and the photodiode that will have light reflection surface and be contained in a single channel optical power monitor in the box.By arranging a plurality of optical power monitors in parallel to each other, also can provide multi-channel optical power monitor assembly.Utilize a multi-channel optical electric diode to replace a plurality of photodiodes of a row, the size that can dwindle this assembly.In optical power monitor of the present invention, the part light by Optical Fiber Transmission weld from upstream side fibre core face leakage to the fibre cladding of downstream; The light reflection surface that the direction that leak light is propagated is provided in the covering of downstream optical fiber changes about 90 °, so that by the covering relative with light reflection surface leak light is transmitted in the air; And emission light is become electric signal by photodiode converts.Because what detect is to come out to enter airborne light from covering, all be taken as noise from the light of adjacent fiber with from the light in the example external world.Therefore, the shielding of light shield between the every pair of adjacent fiber and box all is absolutely necessary.
Best, in optical power monitor of the present invention, be provided in the distance that light reflection surface in the fibre cladding of downstream is positioned at the downstream 4.5 to 7.5mm of weld.
Owing to depend on the curvature of fibre core end face part, the emergence angle of the light can not easily calculating in weld from the fibre core face leakage to the downstream fibre cladding.Many experimental results are verified, if on three rank or quadravalence add and be equipped with light reflection surface on the strong position, then can improve responsiveness.The optical wavelength of use is depended in the position of light reflection surface.But, be equal to or greater than 4.5mm and be equal to or less than on the distance of 7.5mm.The optical wavelength range that is mainly used in communication is that 1520nm is to 1620nm.Three rank or quadravalence add strong position and change with wavelength.But, compare the length long enough of light reflection surface with wavelength.Therefore, the wavelength difference of 100nm can be ignored.
Best, in optical power monitor of the present invention, light reflection surface becomes 38 ° to 45 ° angle with the fibre core optical axis of downstream optical fiber.
Be used for the direction of propagation of light that will be by the covering transmission and change about 90 ° owing to be provided in light reflection surface in the fibre cladding of downstream, best, the light reflection surface angle of the optical axis of optical fiber for the downstream is 38 ° to 45 °.If angle is less than 38 °, then light is reflected by light reflection surface, but most of reflected light is radiated around the covering with such wide-angle, causes the luminous energy that is returned by the covering peripheral reflection to increase.On the contrary, if angle greater than 45 °, then the ratio of the light by light reflection surface transmission has increased, and responsiveness has reduced.By light reflection surface being arranged on 38 ° to 45 ° the angle, can obtain good characteristic.
Best, light reflection surface be in the covering of downstream optical fiber with the side of the weld side of the recess of the fibre core optical axis perpendicular cuts of upstream side optical fiber.Therefore the notched side relative with the side of the weld side of recess, can have Any shape in the face of leaking not influence of reflection of light.In addition, there is no need to specify the shape of notched bottoms.Can easily make recess by machining.For fear of in optical fiber, staying working stress, preferably the section configuration of the recess that will form by the side and the opposite flank of weld side make the symmetry.Especially be preferably formed the V-arrangement recess.As long as the side of weld side and the angle of fiber core optical axis can accurately be set, just can use any other process technology except that machining.For example, the dry etching technology such as ion-milling can be used to form recess.
In optical power monitor of the present invention, best, the bottom of recess and downstream fiber core around between distance be 0.5 to 8 μ m.
Part light by upstream side fibre core transmission to the fibre cladding of downstream, is fused the recess offside reflection of part side from part upstream side fibre core face leakage, is detected by photodiode then.Therefore, importantly, make light radiation reliably to the recess side.If recess is more shallow, that is to say that the area of the recess side of weld side is less, then a part of light can not project on the recess side, makes the light ratio of transmitting by near a part of covering the fibre core increase.Therefore, be necessary with around the fiber core of downstream and the distance limit between the bottom of recess to 8 μ m or littler.On the other hand, although optical fiber is built into by the fibre core transmission ray, between fibre core and covering, there is clear and definite border.Therefore, near a part of covering of some light fibre core leaks into fibre core.If if recess is dark and fibre core around and the distance between the notched bottoms less than 0.5 μ m, then in light that transmits near a part of covering fibre core and the leakage of light by the fibre core transmission space in the recess, cause loss bigger.Therefore, the distance between preferably making around notched bottoms and the fibre core is 0.5 to 8 μ m.
About 90 ° have been changed at weld from part upstream side fiber core face leakage reflects the light of interfering mutually simultaneously and strengthening to the fibre cladding of downstream and in covering the light reflection surface of the direction of propagation in the fibre cladding of downstream.Reflected light passes covering, fibre core and the covering relative with light reflection surface of light reflection surface side, penetrates from downstream optical fiber and goes forward side by side into photodiode.
Best, in optical power monitor of the present invention, the skew between the fibre core optical axis of two optical fiber is 0.05 times to 0.32 times of fibre core diameter.
Can change the luminous energy that leaks in the covering by changing skew.Gaussian distribution is deferred in light distribution in the fibre core.Therefore, the variation of luminous energy is increasing with the skew increase.Normally used single-mode fiber has the core diameter (wavelength: 1310nm) of 9.2 μ m.When the fibre core end was welded together mutually with the skew of 2.5 μ m, responsiveness was about 100mA/W.That uses output current (mA) and the light intensity (W) that enters photodiode from photodiode recently represents responsiveness.
Best, in optical power monitor of the present invention, the surface roughness Ra of light reflection surface is less than 2nm.
The light that transmits in the fibre cladding of downstream is provided in the light reflection surface reflection in the covering, and the light intensity that enters in the photodiode changes with the surfaceness of light reflection surface, that is to say that responsiveness changes with the surfaceness of light reflection surface.If surfaceness increases, then reflected light is dispersed because of light scattering, makes the light that enters in the photodiode die down.If surface roughness Ra is 2nm or littler, then can obtain high-responsivity.Surface roughness Ra is the value of measuring according to JIS B0601.Because the optical wavelength of using is near the long wavelength the 1550nm, regulation surface undulation and regulation surfaceness are effective for improving responsiveness.According to JIS B0601, from envelope fluctuating curve, obtain roughness pattern average length AR.By dwindling AR, can improve the effect of reflection ray with respect to the wavelength that will use.Best, AR be the wavelength that will use 1/2 or shorter.
Best, in optical power monitor of the present invention, formation has the metal film of high reflectance as light reflection surface on the recess side of weld side.
Being equipped with the metal film with high reflectance on the recess side of weld side is effective for improving responsiveness.Can improve the light reflection efficiency of high reflectance optical reflection film by effectively restriction light scattering and the effectively transmission of restricted passage light reflection surface when reflection ray.As metal film, gold (Au), silver (Ag), aluminium (Al) or copper (Cu) with high reflectance are desirable.From stable in time viewpoint, preferably use the Au that is difficult for oxidation, rather than Ag, Al and the Cu of easily oxidation.Can finish the film formation of metal film by evaporation or sputter.Metal film can be provided on whole optical fiber side face and the recessed surfaces, rather than on the optical fiber surface part of photodiode, and on the recess side of weld side.Cover whole optical fiber side face rather than be effective for the influence of restriction ambient light towards the optical fiber surface of photodiode part.
As everyone knows, through moisture, the light transfer characteristic of photodiode changes in time.Therefore, preferably drying nitrogen or dry argon gas are filled in the sealed box of optical power monitor of the present invention.
Best, optical power monitor of the present invention further has first back-up block that supports upstream side optical fiber at the upstream side of weld, and second back-up block that supports downstream optical fiber in the downstream of light reflection surface.Article two, the part of optical fiber between first and second back-up blocks bends to arc, with arch upward in the opposite direction towards the side of photodiode.
Article two, the part of optical fiber between two back-up blocks (first and second back-up blocks) is that the luminous power module of straight line has the average response degree that has improved the 65.2mA/W of about 10mA/W with respect to traditional optical waveguide module as shown in figure 18, but has the responsiveness variation range of 33mA/W.This value is the twice of common required value of responsiveness variation range or more times.Two optical fiber have between two pieces with the optical power monitor of the part that bends to arc towards the side of photodiode in the opposite direction in, the average response degree can further improve, and the responsiveness variation range can narrow down to half.
If the part of two optical fiber between two back-up blocks of optical power monitor is smooth, in other words, the radius-of-curvature infinity of curve, if or this part on the direction of photodiode, bending to arc (hereinafter referred to as " downwards camber line "), then cause responsiveness to reduce.Therefore, making this parts of two optical fiber form such shape does not expect.Therefore, make two optical fiber the part between two back-up blocks with bend to arc (hereinafter referred to as " upwards camber line ") towards the side of photodiode in the opposite direction.Along with the radius-of-curvature of curve reduces, the maximal value and the minimum value of responsiveness alternately appears.Best, two fibre-optical bendings between two back-up blocks are become to have such radius-of-curvature, the responsiveness that makes optical power monitor is near maximal value.
If to the optical fiber stress application, then the light velocity by Optical Fiber Transmission can change.When the fibre-optical bending camber, upwards stress is applied on the interior outside of optical axis of fibre core in the footpath of arc by different way; Diametrically compressive stress is applied on the inboard, diametrically tension stress is applied to simultaneously on the outside.Because optical power monitor of the present invention has the downstream optical fiber that bends to arc, upwards the transmission speed propagated of side is different mutually outside in orphan's footpath in covering for the transmission speed that the light from part upstream side fibre core face leakage to the downstream fibre cladding is upwards propagated in the inboard in the footpath of arc in covering and leak light.Light with different transmission speeds is interfered mutually.Therefore, if light reflection surface is provided in the position that light is strengthened mutually by mutual interference, then can improve responsiveness.The transfer rate of light in covering changes with the stress that puts on optical fiber.Therefore, by changing the radius-of-curvature of optical fiber, can adjust light and add strong position.In the present invention, limit the radius-of-curvature of the part of two optical fiber between two back-up blocks, so that the radius-of-curvature of the part of downstream optical fiber between weld and light reflection surface is arranged to preferred value.
Best, in optical power monitor of the present invention, roughly there is the peak of arc in two optical fiber on the mid point between first and second back-up blocks in the part between first and second back-up blocks.
Best, in the present invention, the distance between first back-up block and the weld equals the distance between the light reflection surface and second back-up block.These distances equate to make the peak of arc can be roughly at the mid point of the part of two optical fiber between first and second back-up blocks.In addition, this peak can be roughly on the mid point between weld and the light reflection surface, and the position strengthened mutually of the light of light reflection surface can being provided in weld from upstream side fibre core face leakage to the downstream fibre cladding, thereby improve the responsiveness of optical power monitor and dwindle the variation range of responsiveness.
Best, the 3rd back-up block is provided in roughly on the mid point between first and second back-up blocks, supporting the part of two optical fiber between first and second back-up blocks, thereby in this part of optical fiber, form the peak of arc.The 3rd back-up block makes the straight line high about 100 μ ms or littler of point midway than the upper surface that connects first and second back-up blocks in the part of two optical fiber of mid point upper support between first and second back-up blocks.Best, the end of the 3rd back-up block that contact with the part of two optical fiber between first and second back-up blocks is that radius is the curved surface of about 1mm, rather than has the edge of acute angle.
Best, in optical power monitor of the present invention, the part of two fibre-optical bending cambers has the radius-of-curvature of 0.086m to 0.111m or 0.347m to 2.667m.
The radius-of-curvature that decides optical fiber by the peak and the distance between the string of distance between the back-up block and arc.But in optical power monitor of the present invention, the sweep of two optical fiber has weld and light reflection surface, that is, and and recess.Owing to this reason, in fact strict, the shape of sweep can not be a circular arc.Therefore, in description of the invention, the shape of sweep is called " arc ".Radius-of-curvature r can pass through r=h/2+L
2/ 8h is from the peak and the acquisition of the distance h between the string of distance L between two back-up blocks and arc.Owing to compare with L, h is very little, can look like r=L
2/ 8h obtains radius-of-curvature like that.
Article two, the responsiveness of the part of optical fiber between two back-up blocks with optical power monitor of the present invention of arc shape upwards generally reduces with the radius-of-curvature of this part and improves.Along with radius-of-curvature begins to reduce from infinity, the maximal value and the minimum value of responsiveness alternately appears.First maximal value appears on the radius-of-curvature of about 0.6m, and second maximal value appears on the radius-of-curvature of about 0.1m.When radius-of-curvature is in 0.347m arrives the scope of 2.667m or in 0.086m arrives the scope of 0.111m, can obtain to surpass the responsiveness of 70mA/W.Between these scopes, that is, in the scope of 0.347m, exist responsiveness the radius-of-curvature of minimum value to occur at 0.111m.Responsiveness on the radius-of-curvature in this scope has the suitable low value of 50mA/W.
Because the responsiveness on second maximum point is higher than the responsiveness on first maximum point, nature can expect using the 3rd maximum point.But, investigate the radius-of-curvature that presents the 3rd maximum point and find to have the minimal value of about 0.01m.Can not become to have the radius-of-curvature of about 0.01m by the fibre-optical bending that quartz is made.Therefore, preferably use near the value of first or second maximum point.In order to guarantee 70mA/W or higher responsiveness, avoid optical fiber fracture in the thermal cycle test simultaneously, select the minimum profile curvature radius of 0.086m.
Best, in optical power monitor of the present invention, distance between first and second back-up blocks be 4.8mm to 14.0mm, and each of the distance between the distance between first back-up block and the weld and the light reflection surface and second back-up block all is that 0.2mm is to 2.0mm.By selecting this size, can obtain the high and little small size optical power monitor of responsiveness variation range of responsiveness.
Optical power monitor of the present invention has: be provided in light transmission upstream side and downstream and have two optical fiber of fibre core, the fibre core end face toward each other, the fibre core optical axis is offset mutually, the fibre core end face is welding mutually in weld; Light reflection surface towards skew in weld and from the outstanding part upstream side fiber core end face of downstream fiber core end face, and is provided in the fibre cladding of downstream; And photodiode, be positioned at relative with described light reflection surface with respect to the downstream fiber core.Three rank of mutually strengthening in the light from upstream side fiber core face leakage to the downstream fibre cladding or quadravalence light are provided in the light reflection surface reflection in the covering and are detected by photodiode.Therefore, though the present invention can provide be designed to the multichannel monitor also can minification and reduce the optical power monitor of optical transmission loss.
Optical power monitor of the present invention can further have at the upstream side of weld and supports first back-up block of upstream side optical fiber and support second back-up block of downstream optical fiber in the downstream of light reflection surface.Article two, the part of optical fiber between first and second back-up blocks bends to arc, with arch upward in the opposite direction towards the side of photodiode.In this case, responsiveness can be further improved and also the responsiveness variation range can be dwindled.
Description of drawings
Fig. 1 is that optical power monitor of the present invention is in the planimetric map of removing under the loam cake state;
Fig. 2 is the skiagraph of optical power monitor of the present invention;
Fig. 3 A is the weld between two optical fiber of explanation and the amplification skiagraph of the recess in the optical fiber of downstream, Fig. 3 B be weld between two optical fiber of explanation along the skiagraph of offset plane, and Fig. 3 C is the cross-sectional view of explanation weld;
Fig. 4 A and 4B illustrate the synoptic diagram that leaks into the propagation of the light the covering from the fibre core of weld;
Fig. 5 is the figure that illustrates at the relation between the distance L 3 (mm) between example 2 described responsivenesses and weld and the light reflection surface;
Fig. 6 be illustrate angle θ 1 at example 3 described responsivenesses and light reflection surface (°) between the figure of relation;
Fig. 7 is the figure that illustrates at the relation between example 4 described responsivenesses and the skew/core diameter;
Fig. 8 is the figure that illustrates at the relation between example 4 described losses and the skew/core diameter;
Fig. 9 is the figure that illustrates at the relation between the surfaceness of example 5 described responsivenesses and light reflection surface;
Figure 10 is the figure that illustrates at the relation between example 6 described responsivenesses and the roughness pattern average length AR (nm) that obtains from the envelope fluctuating curve of light reflection surface;
Figure 11 illustrates with respect to loss, the figure apart from the relation between the d (μ m) between around responsiveness and notched bottoms and the fibre core;
Figure 12 A is the skiagraph according to the optical power monitor of example 8 of the present invention, and Figure 12 B and 12C are the skeleton views that is used in first back-up block in the optical power monitor;
Figure 13 is the figure of the size of the optical fiber between the back-up block in the illustrative examples 8;
Figure 14 is the figure that the relation between the responsiveness and radius-of-curvature r (m) in the example 9 of the present invention is shown;
Figure 15 is the skiagraph of the optical power monitor in the example 10 of the present invention;
Figure 16 is the skiagraph of the optical power monitor in the example 11 of the present invention;
Figure 17 A and 17B are traditional optical power monitor assemblies, and Figure 17 A is a skeleton view, and Figure 17 B is the skiagraph of an optical power monitor in the assembly; And
Figure 18 A and 18B show conventional planar waveguide type optical power monitor, and Figure 18 A is a planimetric map, and Figure 18 B is a skiagraph.
Embodiment
The present invention is described in detail at example of the present invention referring now to accompanying drawing.In order to be easy to describe, represent identical parts or part with identical label.
Example 1
Fig. 1 is that optical power monitor of the present invention is in the planimetric map of removing under the loam cake state.Fig. 2 is the skiagraph of optical power monitor.Fig. 3 A is the weld between two optical fiber of explanation and the amplification skiagraph of the recess in the optical fiber of downstream.Fig. 3 B is that weld between two optical fiber of explanation is along the amplification skiagraph of offset plane.Fig. 3 C is the cross-sectional view of explanation weld.Fig. 4 A and 4B illustrate the synoptic diagram that leaks into the propagation of the light the covering from the fibre core of weld.
Describe the structure of optical power monitor assembly 1 of the present invention in detail referring now to Fig. 1 and 2.Fig. 1 shows 8 channel light power monitor assemblies 1 with 8 optical power monitors that are placed in the box 9.Light transmission upstream side optical fiber 2 and light transmission downstream optical fiber 3 are by protection tube 8 and 8 ' draw from box 9.Loam cake 11 usefulness bonding agent (not shown) are bonded on the box 9.Box 9 is filled with drying nitrogen.The electrode 10 of photodiode 7 is drawn from the sidewall of box 9.The photodiode 7 and the line between the electrode 10 that are laid in the box 9 are not shown.First back-up block 4, second back-up block 4 ' and photodiode 7 usefulness adhesive on the inner bottom surface of box 9.First back-up block 4 and second back-up block 4 ' each all have 8 v-depressions accurately keeping fiber distance.Optical fiber with bonding agent be bonded in first and second back-up blocks 4 and 4 ' v-depression in.Photodiode 7 is arranged on the corresponding part of recess of box inner bottom surface and optical fiber.Except as otherwise noted, in following description, if needed, the every pair of light transmission upstream side optical fiber 2 and the light transmission downstream optical fiber 3 that is bonded with each other is called " optical fiber ".Light shielding plate 30 is provided between every pair of adjacent fiber, to prevent interference of light.
Size, light stream of optical power monitor various piece etc. are described to 3C below with reference to Fig. 3 A.As shown in Figure 3A, the end face of every light transmission upstream side optical fiber 2 and corresponding light transmission downstream optical fiber 3 is welded together mutually, and the skew o between the fibre core optical axis 16 of the fibre core optical axis 15 of light transmission upstream side optical fiber 2 and light transmission downstream optical fiber 3 is configured to 2 μ m.After the skew welding, in optical fiber, form V-arrangement recess 6 by grinding, so that the weld of the center of light reflection surface 14 and optical fiber 5 is at a distance of the distance L 3 of 6.80mm.The degree of depth of recess 6 is 55.0 μ m, and between around notched bottoms 12 and the fibre core is 2.9 μ m apart from d.The side of the weld side of recess 6, that is, light reflection surface 14 has the surfaceness of the angle θ 1, the 1.2nm that become 40.5 ° with the fibre core optical axis and the roughness pattern average length AR of the 580nm that obtains from envelope fluctuating curve.As a reference, the side relative with the weld side of recess 6 has and becomes 45.2 ° angle θ 2 with the fibre core optical axis.By vacuum deposition, the light that forms thickness 0.03 μ m on the recessed surfaces of weld side reflects golden film 20.
The light (solid arrow) of the fibre core transmission by light transmission upstream side optical fiber 2 is divided into the light (dotted arrow) in the covering that leaks into downstream optical fiber 3 and enters light (solid arrow) in the fibre core of downstream optical fiber 3.The light that enters in the fibre core of downstream optical fiber 3 passes fibre core, and once also can not come out to enter the air from fibre core.In traditional optical power monitor, the light in the measure portion at least once comes out to enter in the air and turns back in optical fiber or the optical waveguide.One of feature of optical power monitor of the present invention is that the light except the leak light that enters photodiode once can not come out to enter in the air yet.This is one of reason that effectively reduces loss.In the light that leaks at weld 5 in the covering, three rank or quadravalence light are interfered mutually in repeated reflection in covering and are strengthened mutually.The light path of these light is made these light can pass covering, fibre core and the covering of downstream optical fiber 3 by light reflection surface 14 crooked about 90 ° angles of recess 6, comes out to enter to go forward side by side in the air in the photodiode 7, is converted into electric signal.
Describe the skew weld 5 of the fibre core in the zone that is present in the circle A indication among Fig. 3 A in detail below with reference to Fig. 3 B and 3C.Fig. 3 B is the skiagraph along the weld of offset plane.The fibre core of the fibre core of light transmission upstream side optical fiber 2 and light transmission downstream optical fiber 3 links together by fusion, forms curved surface 17.Enter in the covering and be repeated with various angles to the light in the fibre cladding of downstream by curved surface 17 transport leaks and in covering, propagate reflectingly.The light of repeated reflection is interfered mutually and is caused strengthening mutually or weakening.Curved surface 17 has the critical function that light is interfered.Fig. 3 C illustration from the fibre core transversal section of the downstream optical fiber 3 direction welds of seeing over.The fibre core of upstream side optical fiber 2 is outstanding from the core segment of downstream optical fiber 3, to form crescent part 18 in the fibre core end face.
Fig. 4 A and 4B are the figures that schematically illustrated crescent part 18 from the upstream side fibre core end face that the downstream fibre core is given prominence to leaks into the flow direction of the light in the fibre cladding of downstream.Fig. 4 A is illustrated in the offset planes, the flow direction of the light in the covering of downstream optical fiber 3.The direction that the crescent part 18 of leak light from upstream side fibre core end face come out diverges to different directions at curved surface.Be repeated in covering, to propagate reflectingly on the circumference of covering as the light that comes out with angle θ u of dotted arrow indication with as the light that comes out with angle θ d of solid line arrow indication.Therefore, these light are strengthened on the more approaching mutually position of the fibre core end of dotted arrow and solid arrow mutually.Supposing first, to add strong position be that the light reflection surface 14 of single order position and recess 6 is provided in for the third time (three rank) or the 4th time (quadravalence) adds on the strong position.The direction of light ray propagation has changed about 90 ° angle on light reflection surface, and the direction of light after change propagates into photodiode 7.Weak point and add strong position and alternately occur.Fig. 4 B shows the light stream in the section vertical with offset plane.The light that crescent part 18 from the fibre core end face is come out is symmetrical with respect to fibre core optical axis 16 (corresponding to the offset plane among Fig. 4 B).Therefore, light ray propagation is reflected around covering simultaneously, does not interfere mutually, and arrives light reflection surface.In this example, angle θ u is that 14.0 ° and angle θ d are 9.6 °.
With wavelength is that 1550nm and light intensity are in 20 complete optical power monitor assemblies of light input of 1.2mW, with assessment optical power monitor characteristic.Owing to used 20 8 channel element, so measured the characteristic of 160 channels altogether and calculating mean value from measurement result.The loss of good value :-0.72dB and the responsiveness of 64.4mA/W have been obtained.Being placed on light shielding plate between the optical fiber makes to crosstalk and is reduced to-48.3dB.Do not comprise protection tube 8 and 8 ' and the external dimensions of the box that has loam cake 11 9 of electrode 10 are 23mm L * 17mmW * 2.6mm H.Therefore, the volume-diminished of optical power monitor assembly of the present invention is to 1/5 of the volume of traditional optical power monitor assembly shown in Figure 17 A.
Example 2
Fig. 5 is the responsiveness (mA/W) that photodiode is shown and the figure of the relation between the distance L 3 (mm) between weld and the light reflection surface.On one side the distance L between weld and the light reflection surface 3 is changed to 9.0mm from 0.8mm, Yi Bian measure responsiveness.Other factors except distance L 3, that is, the size of shape (angle), recess, light reflecting metallic film etc. are identical with in the example 1 those.As can be seen, when the distance L between weld and the light reflection surface 3 is about 1mm, when distance is about 3mm, when distance was about 5mm, when distance is about 7mm and when distance is about 9mm, responsiveness was higher, and when distance is about 2mm, when distance was about 4mm, when distance is about 6mm and when distance is about 8mm, responsiveness was lower.High-responsivity point is strengthened corresponding to the interference of light, and low-response degree point weakens corresponding to the interference of light.On the distance of about 1mm, light is strengthened by elementary interference.Ordinal number is big more, and responsiveness is high more.High-responsivity appears on three rank and the quadravalence position.Can prove, utilize three rank or quadravalence interference light can obtain to have the optical power monitor of high-responsivity.
Example 3
Fig. 6 be angle θ 1 that responsiveness (mA/W) and light reflection surface and downstream fibre core optical axis are shown (°) between the figure of relation.Distance L between weld and the light reflection surface is fixed on 6.80mm and uses the quadravalence interference light.Optical power monitor is by allowing the angle θ 1 of light reflection surface change to 60 ° of formation from 28 °.Responsiveness measuring method and optical reflection film etc. are identical with in the example 1 those.When angle θ 1 was in 38 ° to 45 ° scope, responsiveness was higher than 60mA/W, but when angle is reduced to below 38 ° and when angle surpasses 45 °, responsiveness descends suddenly.The reason that is considered to responsiveness decline as described below.When angle during less than 38 °, light is reflected by light reflection surface, but the angle that reflected light is radiated around the optical fiber increases.That is to say that the luminous energy that is turned back to covering by the reflection of covering side face increases.This is considered to because light is incident on the covering side face with the angle greater than 14 °.When angle during greater than 45 °, the ratio of the light by the light reflection surface transmission increases, and causes responsiveness to reduce.
Example 4
Fig. 7 is the figure that the relation between responsiveness (mA/W) and the skew/core diameter is shown.Form optical power monitor by allowing skew/core diameter than changing to 0.32 from 0.02.Responsiveness measuring method in the example 4, the position of light reflection surface and angle and light reflecting metallic film etc. are identical with in the example 1 those.Responsiveness is more and more higher with the increase of skew/core diameter.When skew increased, the luminous energy that leaks in the fibre cladding of downstream also increased.Thus, the luminous energy that is incident on the light reflection surface increases.Consequently, the luminous energy that enters in the photodiode increases, and makes responsivity value become big.High-responsivity means, even lower by the light intensity of Optical Fiber Transmission, also can accurately monitor.But, this means the light that from light, has extracted higher proportion by Optical Fiber Transmission.With regard to loss, this is disadvantageous.
Fig. 8 illustrates loss (dB) and the figure of the relation between the skew/core diameter.As can be seen, when skew/core diameter ratio increased, loss also increased.This means that the speed that the light intensity by Optical Fiber Transmission reduces is more and more higher.Determine the performance of optical power monitor by the balance between responsiveness and the loss.By in 0.05 to 0.32 scope, skew/core diameter being set, can obtain the high-performance optical power monitor of high-responsivity and low transmission loss.
Example 5
Fig. 9 is the figure that the relation between responsiveness (mA/W) and the light reflection surface roughness Ra (nm) is shown.Optical power monitor forms by allowing light reflection surface roughness Ra change to 10.0nm from 0.1nm.Surfaceness is to realize by the granularity that changes the diamond lap wheel.As the example of measuring roughness, prepared be used in optical power monitor in measure the identical optical fiber of fiber type of responsiveness.On sample optical fiber, cut out recess by the processing identical, and it uses by fractureing in indent with the processing that the optical fiber of optical power monitor is taked.According to JIS B0601, utilize the sonde-type surface roughness tester to come measure surface roughness Ra.With golden vacuum deposition on two sides of recess as optical reflection film.Light is by the interface reflection between covering and the gold.Therefore, if scattered reflection appears in surfaceness height easily.Can confirm that when surfaceness increases to 2nm when above, responsiveness descends suddenly.Think owing to scattered reflection forms such effect.
Example 6
Figure 10 be responsiveness (mA/W) is shown and the roughness pattern average length AR (nm) that from the envelope fluctuating curve of light reflection surface, obtains between the figure of relation.Optical power monitor forms by allowing AR change to 2800nm from 100nm.Surface roughness Ra is configured to 1.2nm.Other condition is identical with in the example 1 those.As the example of measuring roughness pattern average length AR, prepared be used in optical power monitor in measure the identical optical fiber of fiber type of responsiveness.On sample optical fiber, cut out recess by the processing identical, and it uses by fractureing in indent with the processing that the optical fiber of optical power monitor is taked.Measure AR according to JISB0631.When roughness pattern average length AR increased, the fluctuating cycle of light reflection surface caused responsiveness to be subject to the influence that rises and falls more and more near the wavelength of the light that passes through Optical Fiber Transmission.Observation is reduced by the caused responsiveness of the interference between the light of light reflection surface reflection.Can confirm that approximately 800nm or shorter roughness pattern average length AR are preferred.800nm is corresponding to about 1/2 of the optical wavelength of using.
Example 7
Figure 11 illustrates responsiveness (mA/W), loss (dB) and the figure apart from the relation between the d (μ m) between notched bottoms and the fibre core periphery.Optical power monitor changes to 15 μ m apart from d from 0.2 μ m and forms by allowing.Other condition except distance d is all identical with in the example 1 those.When distance d when 0.5 μ m is in the scope of 8 μ m, responsiveness does not change basically.Along with distance d increases since 8 μ m, responsiveness descends gradually, because the area of light reflection surface has reduced.On the contrary, along with distance d shortens since 0.5 μ m, the bottom that makes recess is very near fibre core.In optical fiber, light mainly transmits by fibre core.But in fact, some luminous energy leak near the covering of fibre core.The light that leaks by the recess offside reflection so that be monitored.Therefore, as distance d during less than 0.5 μ m, responsiveness raises, but loss also increases.Can prove, when distance d when 0.5 μ m is in the scope of 8 μ m, can obtain that responsiveness changes and the light stable power monitor of loss reduction.
Example 8
Figure 12 A is the skiagraph according to the optical power monitor of example 8 of the present invention.Light transmission upstream side optical fiber 2 and light transmission downstream optical fiber 3 along first and second back-up blocks 4 and 4 ' in V-arrangement skewed slot 41 place and be fixed therein with resin.Their acclivity of back-up block 4 and 4 ' be placed with toward each other.Therefore, two optical fiber 2 and 3 be present in back-up block 4 and 4 ' between weld and the about mid point between the recess be raised so that have arc upwards.
Each of Figure 12 B and 12C all shows the state at first back-up block, 4 upper support upstream side optical fiber 2.With reference to Figure 12 B, v-depression 41 is by the 0.14 ° of formation of lower surface inclination with respect to back-up block.The degree of depth of v-depression 41 is such, when being placed on optical fiber 2 in the groove, and the upper surface 4 μ m of optical fiber 2 outstanding back-up blocks.Optical fiber is placed and by being adhesively fixed in this v-depression 41 along this v-depression 41, thereby makes optical fiber form the upwards shape of camber line.With reference to Figure 12 C, form the v-depression 41 parallel with the upper surface of back-up block 4, after this, the lower surface that makes back-up block is with respect to 0.14 ° of angle of upper surface inclination.In optical power monitor of the present invention, can use every kind of back-up block shown in Figure 12 B and 12C.Form back-up block by the machining quartz wedge.
The size of each part of the optical power monitor in the example 8 shown in Figure 12 A is described below with reference to Figure 13.Back-up block 4 and 4 ' between distance L be 8mm.Distance L 1 between first back-up block 4 and the weld 5 is 1.5mm, and recess 6 and second back-up block 4 ' between distance L 2 are 1.5mm.Distance L 3 between weld 5 and the recess 6 is 5mm.First and second back-up blocks 4 and 4 ' inside surface between distance L be L1+L3+L2.Rise h according to (chord length of camber line) L of the distance between first and second back-up blocks and optical fiber can pass through r=h/2+L
2/ 8h obtains the radius-of-curvature r of two optical fiber of upstream and downstream side.Owing to compare with L, h is very little for rise, can carry out approximate treatment r=L
2/ 8h.Article two, the rise h of optical fiber 2 and 3 on the mid point between the back-up block is 93 μ m, and the radius-of-curvature r of optical fiber is 0.086m.
50 of this example 8 channel light power monitor are used to obtain the responsiveness of 400 optical power monitors according to the present invention.The responsiveness that obtains be 62.3mA/W to 78.5mA/W, and their mean value is 74.0mA/W.Can obtain to have the optical power monitor of the finite response degree variation range of good response degree and 16.2mA/W.Compare with traditional optical power monitor, responsiveness has on average improved 13.5%, and the responsiveness variation range narrows down to conventional monitors half.
Example 9
Figure 14 is the figure that the relation between the radius-of-curvature r (m) of responsiveness (mA/W) and optical fiber is shown.Used size L1 identical to L3 with in the example 1 those, use with the radius-of-curvature of the v-depression of various angle tilts and the part of two optical fiber between back-up block from downward camber line-0.16m change to camber line upwards+optical power monitor of 0.067m.The state that radius-of-curvature ∞ among Figure 14 is parallel to each other corresponding to two optical fiber.The horizontal ordinate representative of figure is in the logarithmic scale radius-of-curvature of ∞ point both sides.The negative curvature radius is represented downward camber line, and the positive curvature radius is represented upwards camber line.With the responsiveness on the corresponding radius-of-curvature ∞ point of the parastate of two optical fiber be 68mA/W.Responsiveness reduces with the absolute value of the radius-of-curvature of downward camber line and descends.When radius-of-curvature be-during 0.16m, responsiveness drops to the value less than 40mA/W.From this result, as can be seen, under the situation that forms downward camber line, can not improve responsiveness.On the other hand, responsiveness reduces with the radius-of-curvature of camber line upwards and raises.The scope of radius-of-curvature, can obtain 70mA/W or higher responsiveness from+2.667m to+0.347m.Along with radius-of-curvature further reduces, responsiveness temporarily descends, and has minimum value and have the maximal value of 75mA/W once more on+0.16m on+0.10m.Near the radius-of-curvature that+0.10m, reaches 70mA/W or higher responsiveness at+0.111m in the scope of+0.086m.In addition, from this result, as can be seen, form the upwards shape of camber line by making optical fiber, and be provided with radius-of-curvature+2.667m in the scope of+0.347m or at+0.111m in the scope of+0.086m, can obtain 70mA/W or higher responsiveness.
Example 10
Figure 15 shows the skiagraph of the optical power monitor in the example 10 of the present invention, wherein, optical fiber is fixed on the framework of box, and forms the upwards shape of camber line.Box 9 ' framework on form 1 ° slope, and utilize bonding agent will insert protection tube 8 and 8 ' in optical fiber 2 and 3 fix on the slope.Mainly laterally mobile at back-up block 4 and 4 ' middle formation v-depression in order to prevent optical fiber, therefore, there is not the slope.Two back-up blocks and two optical fiber do not interfix.Therefore, two optical fiber form continue to pass through box 9 ' whole inner chamber and the upwards shape of camber line between two back-up blocks.The radius-of-curvature of the optical power monitor of the manufacturing that obtains between back-up block is 1.212m, 0.552m and 0.098m.The responsiveness relevant with these radius-of-curvature is 71.3mA/W, 75.2mA/W and 74.3mA/W, quite mates with the value as shown in figure 14 about example 9.Therefore, optical fiber is fixed on the frame part of box, the validity of the shape of camber line obtains confirming to make optical fiber form upwards.
Example 11
Figure 16 shows the skiagraph of the optical power monitor in the example 11 of the present invention, wherein, utilizes the 3rd back-up block to make the part of two optical fiber between first and second back-up blocks form the upwards shape of camber line.First and second back-up blocks 4 and 4 ' utilize adhesive on the inner bottom surface of box 9 with the 3rd back-up block 33.Back-up block 4 and 4 ' have v-depression, but be not furnished with the slope.The height of the 3rd back-up block 33 is adjusted under two optical fiber 2 and 3 states of placing along v-depression, two back-up blocks 4 and 4 ' mid point on the optical fiber 9 μ m that raise.With adhesive upstream side and downstream optical fiber 2 and 3, so as along first and second back-up blocks 4 and 4 ' in v-depression extend.The 3rd back-up block 33 is made by the thermal expansivity quartz identical with optical fiber.The end of the 3rd back-up block 33 that will contact with optical fiber is made into the curved surface that radius is 1mm.Have only the part of optical fiber between first and second back-up blocks to form the upwards shape of camber line, and the distance between first and second back-up blocks is configured to 8mm.Thus, the radius-of-curvature of the appropriate section of optical fiber is configured to 0.89m.Responsiveness is 73.2mA/W, and is quite consistent with value as shown in figure 14 about example 9.
Owing to have only the part of two optical fiber between two back-up blocks to form the upwards shape of camber line, if radius-of-curvature is too little, then the probability that fractures at recess 6 places of optical fiber increases.By the distance between first and second back-up blocks is changed to 20mm from 4, can obtain the radius-of-curvature that optical fiber fractures.The radius-of-curvature that obtains is that 0.15m is to 0.25m.Can find, in this example of the present invention, can make and have the 2.667m that can obtain 70mA/W or bigger responsiveness the upwards optical fiber of arc shape, have the optical fiber of 0.111m to the arc shape that makes progress of 0.086m radius-of-curvature but can not make to the 0.347m radius-of-curvature.But, can reduce the upwards variation of camber line peak position, so that the responsiveness that reduces to be considered to by the camber line peak position that makes progress causes changes.Therefore, this radius-of-curvature that is arranged in is effective big the time.
Example 12
In order to check that the responsiveness in the middle of the optical power monitor with the identical optical fiber of radius-of-curvature changes, under the condition in example 8, make 50 to 60 8 channel light power monitor assemblies, and measure the responsiveness of these monitors at every kind of different curvature radius.At 400 to 480 optical power monitors of every kind of radius of curvature measurement.The quantity that is used in the radius-of-curvature in the measurement is 12.As shown in table 1, radius-of-curvature from downward camber line-1.6m change to camber line upwards+8.1m.The radius-of-curvature of camber line is represented with negative value downwards, and upwards the radius-of-curvature of camber line is used on the occasion of representing.For relatively, also be equipped with and test 200 traditional optical power monitors, and import 1600 measured values as sample group M.The radius-of-curvature of conventional articles be distributed in downward camber line-0.3m to camber line upwards+0.3m between.
In table 1, the measurement result of responsiveness is shown with the difference of minimum value, maximal value, mean value and maximal value and minimum value.Sample group A and B have the optical fiber of downward camber line form; Sample group C has the smooth optical fiber that radius-of-curvature is ∞; Sample group D has the upwards optical fiber of camber line form to L; And sample group M is a conventional articles.The radius-of-curvature of each sample group is not a measured value, but design load.But the several samples of actual measurement are to confirm the coupling between measured value and the design load.The average response degree surpass 70mA/W those be among sample group E, F, G, I and the J, and their radius-of-curvature is 1.600m, 0.800m, 0.400m, 0.100m and 0.086m.In example 9, the radius-of-curvature that the average response degree surpasses 70mA/W is 2.667m to 0.347m or 0.111m to 0.086m.The value of sample group E, F, G, I and J is included in these scopes.The variation range of the responsiveness of these sample groups be 14.6mA/W to 16.2mA/W, be half of conventional articles.In radius-of-curvature is among the sample group H of the 0.267m outside this scope, responsiveness even also be lower than 70mA/W on maximal value.Conventional articles sample group M has and comprises those the range of curvature radius of sample group A to G.The maximal value of radius-of-curvature and minimum value all the sample group A in this scope have the minimum response degree of 46.5mA/W and the peak response degree of 81.4mA/W to G.Can think that the minimum response degree of the 46.5mA/W of these responsivenesses and conventional articles and the peak response degree of 79.5mA/W mate very much.
Table 1
| The sample group | Arc | Responsiveness (mA/W) | ||||
| Camber line | Radius-of-curvature (m) | Minimum value | Maximal value | Mean value | Scope (maximal value-minimum value) | |
| A | Downwards | -1.600 | 46.5 | 79.1 | 62.9 | 32.6 |
| B | Downwards | -6.500 | 51.2 | 78.8 | 65.8 | 27.6 |
| C | Smooth | ∞ | 54.1 | 79.4 | 66.9 | 25.3 |
| D | Upwards | +8.100 | 61.3 | 79.5 | 69.1 | 18.2 |
| E | Upwards | +1.600 | 64.1 | 79.5 | 72.0 | 15.4 |
| F | Upwards | +0.800 | 66.8 | 81.4 | 74.1 | 14.6 |
| G | Upwards | +0.400 | 65.9 | 81.2 | 73.5 | 15.3 |
| H | Upwards | +0.267 | 52.9 | 68.7 | 60.7 | 15.8 |
| I | Upwards | +0.100 | 66.7 | 82.3 | 74.6 | 15.6 |
| J | Upwards | +0.086 | 62.3 | 78.5 | 74.0 | 16.2 |
| K | Upwards | +0.080 | 53.3 | 72.5 | 62.8 | 19.2 |
| L | Upwards | +0.067 | 43.4 | 60.8 | 51.7 | 17.4 |
| M | Tradition | 46.5 | 79.5 | 65.2 | 33.0 | |
By to make two optical fiber between the back-up block form radius-of-curvature be 2.667m to 0.347m or 0.111m to the arc shape that makes progress of 0.086m, can obtain 70mA/W or higher average response degree.The variation range of responsiveness can also be narrowed down to half of conventional articles.
Claims (14)
1. optical power monitor comprises:
Article two, optical fiber, every optical fiber have the fibre core that is in its center and around the covering of fibre core, two optical fiber are in the upstream side and the downstream of light transmission respectively, and their end face weld in the face of and welding mutually, their fibre core optical axis is offset mutually;
Light reflection surface is arranged in the covering of downstream optical fiber, towards in weld skew and from the part end face of the outstanding upstream side fiber core of the end face of downstream fiber core, and with the fibre core optical axis of downstream optical fiber at an angle; And
Photodiode, be arranged to relative with described light reflection surface with respect to the downstream fiber core, so that detect by the transmission of upstream side fiber core, from skew and the light that to the covering of downstream optical fiber and by described light reflection surface, reflects from the part face leakage of the outstanding upstream side fiber core of the end face of downstream fiber core
Wherein, described light reflection surface is arranged in from the part face leakage of upstream side fiber core to position that the light of the covering of downstream optical fiber is interfered mutually and strengthened.
2. optical power monitor according to claim 1, wherein, described light reflection surface is arranged in from the part face leakage of upstream side fiber core to the 3rd or the 4th position that the light of the covering of downstream optical fiber is interfered mutually and strengthened.
3. optical power monitor according to claim 2, wherein, described light reflection surface is positioned at the distance of the downstream 4.5mm of described weld to 7.5mm.
4. optical power monitor according to claim 1, wherein, described light reflection surface becomes 38 ° to 45 ° angle with the fibre core optical axis of downstream optical fiber.
5. optical power monitor according to claim 2, wherein, described light reflection surface be in the covering of downstream optical fiber with the side of the weld side of the recess of the fibre core optical axis perpendicular cuts of downstream optical fiber.
6. optical power monitor according to claim 5, wherein, the distance between the periphery of the bottom of described recess and downstream fiber core is that 0.5 μ m is to 8 μ m.
7. optical power monitor according to claim 5, wherein, the surface roughness Ra of described light reflection surface is less than 2nm.
8. optical power monitor according to claim 5, wherein, described light reflection surface is the metal film that forms on the side of the weld side of recess.
9. optical power monitor according to claim 1, wherein, the skew between the fibre core optical axis of two optical fiber is 0.05 times to 0.32 times of fibre core diameter.
10. optical power monitor according to claim 1, the upstream side that further is included in described weld supports first back-up block of upstream side optical fiber and supports second back-up block of downstream optical fiber in the downstream of described light reflection surface, wherein, article two, the part of optical fiber between first and second back-up blocks bends to arc, to arch upward on the direction opposite with photodiode.
11. optical power monitor according to claim 10, wherein, two optical fiber the part between first and second back-up blocks roughly the mid point between first and second back-up blocks have the peak of arc.
12. optical power monitor according to claim 11, wherein, two optical fiber is supported by the 3rd back-up block of the mid point between first and second back-up blocks roughly in the part between first and second back-up blocks.
13. optical power monitor according to claim 10, wherein, the part of two fibre-optical bending cambers has the radius-of-curvature of 0.085m to 0.111m or 0.347m to 2.667m.
14. optical power monitor according to claim 10, wherein, distance between first and second back-up blocks be 4.8mm to 14.0mm, and the distance between the distance between described first back-up block and the weld and the described light reflection surface and second back-up block is that 0.2mm is to 2.0mm.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006070967A JP4051687B2 (en) | 2006-03-15 | 2006-03-15 | Optical power monitor |
| JP2006070967 | 2006-03-15 | ||
| JP2006265106 | 2006-09-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101038356A true CN101038356A (en) | 2007-09-19 |
Family
ID=38593113
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007100881305A Pending CN101038356A (en) | 2006-03-15 | 2007-03-15 | Optical power monitor |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP4051687B2 (en) |
| CN (1) | CN101038356A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103513349A (en) * | 2013-09-24 | 2014-01-15 | 广西安捷讯电子科技有限公司 | Light power monitor |
| CN104977666A (en) * | 2014-04-04 | 2015-10-14 | 日立金属株式会社 | Duplex LC Communication Light Detecting Adapter And Duplex LC Communication Light Detecting Structure |
| CN110455495A (en) * | 2019-07-31 | 2019-11-15 | 华中科技大学鄂州工业技术研究院 | A kind of optical fiber laser mode stability detection device and method |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5011179B2 (en) * | 2008-03-18 | 2012-08-29 | 株式会社フジクラ | High power optical connector |
| JP5235525B2 (en) * | 2008-06-19 | 2013-07-10 | 三菱電機株式会社 | Laser light transmission device and fiber laser oscillator including the same |
| JP5133930B2 (en) * | 2009-03-31 | 2013-01-30 | アンリツ株式会社 | Optical modulator module |
| JP6093525B2 (en) * | 2012-08-31 | 2017-03-08 | 株式会社オーク製作所 | Illumination monitoring apparatus and exposure apparatus provided with the same |
| JP2015087661A (en) * | 2013-10-31 | 2015-05-07 | 住友大阪セメント株式会社 | Optical waveguide device |
| JP6205300B2 (en) * | 2014-04-04 | 2017-09-27 | 日立金属株式会社 | Communication light visualization module |
-
2006
- 2006-03-15 JP JP2006070967A patent/JP4051687B2/en not_active Expired - Fee Related
-
2007
- 2007-03-15 CN CNA2007100881305A patent/CN101038356A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103513349A (en) * | 2013-09-24 | 2014-01-15 | 广西安捷讯电子科技有限公司 | Light power monitor |
| CN104977666A (en) * | 2014-04-04 | 2015-10-14 | 日立金属株式会社 | Duplex LC Communication Light Detecting Adapter And Duplex LC Communication Light Detecting Structure |
| CN104977666B (en) * | 2014-04-04 | 2017-12-01 | 日立金属株式会社 | Duplexing formula LC Communication ray detection adapter and duplexing formula LC communication light-detecting structures |
| CN110455495A (en) * | 2019-07-31 | 2019-11-15 | 华中科技大学鄂州工业技术研究院 | A kind of optical fiber laser mode stability detection device and method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2007248732A (en) | 2007-09-27 |
| JP4051687B2 (en) | 2008-02-27 |
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