JP3809724B2 - Optical isolator module and optical isolator parts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical isolator module that is incorporated in a semiconductor laser module having a semiconductor laser element and a condensing lens and constitutes an optoelectronic device used for optical communication, an optical information system, and the like. When the laser beam is incident on the transmission system, the reflected laser beam generated in the transmission system does not easily return to the semiconductor laser element without reducing the coupling efficiency of the laser beam to the optical fiber (that is, the semiconductor laser of the reflected laser beam). The present invention relates to an improvement of an optical isolator module in which re-coupling to an element is unlikely to occur and an optical isolator component incorporated in the optical isolator module.
[0002]
[Prior art]
The optical isolator of the optical isolator module incorporated in the semiconductor laser module transmits a laser beam (hereinafter abbreviated as LD light) emitted from a semiconductor laser element (laser diode: abbreviated as LD) by an optical fiber. The function of preventing reflected laser light (hereinafter abbreviated as “reflected LD light”) generated in the transmission system from returning to the LD side when entering the system, that is, preventing unstable oscillation of the LD due to the reflected return light, thereby reducing the LD. It functions to suppress noise.
[0003]
For this reason, when an optical element is mounted on the optical isolator module, processing for preventing reflected LD light from each optical element interface is an important matter in designing the optical isolator module.
[0004]
By the way, as a process for preventing the reflected LD light from the optical element interface, a method of applying an antireflection film is usually employed, but it is often insufficient to provide the antireflection film. Therefore, when an optical element is mounted on the optical isolator module, a method is adopted in which the normal vector of the light incident / exit surface of the optical element is arranged with an inclination angle so as not to be parallel to the traveling direction of the LD light. . In other words, when the LD light emitted from the LD is reflected at the interface of the optical element, the reflected return light to the LD can be suppressed by arranging the optical element so that the reflected LD light does not return to the LD side.
[0005]
An optical isolator module configured based on such a concept is disclosed in Japanese Patent Laid-Open No. 6-194548. That is, as shown in FIG. 5, the optical isolator module includes a ferrule b on which an optical fiber a whose tip is inclined, an optical isolator c arranged on the light incident side of the ferrule b, and the light of the optical isolator c. The main part is composed of a transparent body d having a wedge-shaped cross section disposed on the incident side, and the inclined surfaces of the optical fiber a and the transparent body d are inclined in opposite directions, and the inclination angle (θ) is It is set to be equal.
[0006]
Then, as shown in FIG. 5, the LD light emitted from the LDe and condensed by the condenser lens f has its optical path bent by the action of the transparent body d and is incident obliquely on the end face of the optical isolator c. The reflected LD light at the c end face is difficult to return to the LDe, and the end face of the optical fiber a is inclined by the action of the transparent body d even though the end face of the optical fiber a forms an inclined surface. Since the light path is obliquely incident with the optical path tilted by about 1 / 2θ in the direction opposite to the direction, a decrease in the optical coupling is suppressed.
[0007]
As described above, in the optical isolator module shown in FIG. 5, the reflected LD light at the interface of each optical element is deflected from the LDe, and at the same time, the refraction of the light at the inclined surface in the optical fiber a is effected by the transparent body d. Therefore, the optical isolator c and the optical fiber a can be arranged in a straight line with respect to the optical axis of the LDe as shown in FIG.
[0008]
[Problems to be solved by the invention]
Incidentally, in the optical isolator module shown in FIG. 5, the reflected LD light on the LDe side surface of the transparent body d does not return to the LDe side as shown in the ray tracing diagram of FIG. 6B. It was possible to obtain an effect as described in Kaihei 6-194548.
[0009]
However, since the direction of the reflected LD light on the back surface of the transparent body d does not deviate as much as the surface of the LDe side as shown in the ray tracing diagram of FIG. 6A, a part of the reflected LD light returns to the LDe side. was there.
[0010]
In addition, in the semiconductor laser module, the back surface of the transparent body d close to the condensing point of the condensing lens f because the LD light emitted from the LDe is condensed by the condensing lens f and coupled to the optical fiber a. Since the reflected LD light at the surface has a less diffusing effect and is easily recombined with the condenser lens f, a considerable amount of the reflected LD light reflected on the back surface of the transparent body d returns to the LDe side. Was.
[0011]
This phenomenon also applies to the reflected LD light at each interface of the optical isolator c having an interface parallel to the back surface of the transparent body d, and the interface of the optical isolator c closest to the condensing point of the condenser lens f ( That is, there is a problem that the reflected LD light from the optical isolator interface on the optical fiber side is more likely to return to the LDe side.
[0012]
As a method for solving this problem, there is a method of setting the angle of the inclined surface in the transparent body d to be larger than the value (8 degrees) described in JP-A-6-194548, for example, about 20 degrees. Conceivable. However, when the angle of the inclined surface is set as large as 20 degrees, the coupling efficiency of the LD light to the optical fiber a is reduced due to the aberration in the transparent body d, and the LD light incident on the optical fiber is significantly reduced. It had a problem that caused another problem such as.
[0013]
In JP-A-6-194548, as shown in FIG. 7, the optical isolator c and the transparent body d are arranged obliquely with respect to the optical axis of the LDe, so that the reflected LD light is difficult to return to the LDe side (that is, An optical isolator module having a structure in which re-coupling of reflected LD light to the LD hardly occurs is also disclosed.
[0014]
However, in the optical isolator module shown in FIG. 7, since a plate-like transparent body is applied instead of a transparent body having a wedge-shaped cross section, the optical path of the LD light is inclined about 1 / 2θ with respect to the end face of the optical fiber a. In this state, the incident light cannot be obliquely incident, so that the coupling efficiency of the LD light with respect to the optical fiber a is lowered.
[0015]
The present invention has been made paying attention to such problems, and the problem is that re-coupling of the reflected LD light to the LD can be prevented without reducing the coupling efficiency of the LD light to the optical fiber. An object of the present invention is to provide an optical isolator module and to provide an optical isolator component incorporated in the optical isolator module.
[0016]
[Means for Solving the Problems]
That is, the invention according to claim 1
A ferrule equipped with an optical fiber whose tip is inclined, an optical isolator disposed on the light incident side of the ferrule, and a transparent body disposed on the light incident side of the optical isolator, and is emitted from the semiconductor laser element and On the premise of an optical isolator module that allows the laser light collected by the condenser lens to pass through the transparent body and the optical isolator and enter the tip of the optical fiber,
The transparent body is made of a transparent material having a wedge-shaped cross section having a light incident surface inclined in a direction opposite to the inclination direction of the tip of the optical fiber, and each light incident / exit surface of the optical isolator and the light input on the optical isolator side of the transparent body are formed. The optical isolator and the transparent body are arranged obliquely so that the emission surface is inclined in the same direction as the inclination direction of the optical fiber tip with respect to the optical axis of the optical fiber in the ferrule.
[0017]
And according to the optical isolator module which concerns on invention of Claim 1,
Since the transparent body is made of a transparent material having a wedge-shaped cross section having a light incident surface inclined in a direction opposite to the inclination direction of the tip of the optical fiber, it is possible to prevent a reduction in coupling efficiency of LD light to the optical fiber. It becomes.
[0018]
Also, the optical isolator and the optical isolator are transparent so that each light entrance / exit surface of the optical isolator and the light entrance / exit surface on the optical isolator side of the transparent body are inclined in the same direction as the inclination direction of the optical fiber tip with respect to the optical axis of the optical fiber in the ferrule. Since the body is arranged obliquely, the optical axis direction until it enters the transparent body having a wedge-shaped cross section is the optical axis direction of the optical fiber without setting the inclination angle of the transparent body as large as about 20 degrees as described above. It becomes possible to prevent the recombination of the reflected LD light with respect to the semiconductor laser element set in parallel or substantially parallel.
[0019]
By the way, in the optical isolator module according to claim 1, the transparent body is disposed on the light incident side of the optical isolator. However, when the transparent body and the optical isolator are integrated, the assembly work of the optical isolator module is simplified. Can be planned. The invention according to claim 2 relates to an invention specified based on such technical reasons.
[0020]
That is, the invention according to claim 2
Based on the optical isolator module according to the invention of claim 1,
The polarizer of the optical isolator and the transparent body are bonded via an optical adhesive.
[0021]
In the invention according to claim 2, when an optical adhesive having an approximate refractive index is applied to each material constituting the polarizer and the transparent body, light reflection at the interface between the transparent body and the optical isolator is reduced. Thus, recombination of the reflected LD light with respect to the semiconductor laser element can be prevented more reliably.
[0022]
Next, when assembling the optical isolator module according to the present invention, since the transparent body is disposed on the light incident side of the optical isolator, the transparent body is directly bonded to the end face of the cylindrical magnet forming a part of the optical isolator. There is a case. The transparent body is made of a transparent material such as glass, and the thermal expansion coefficient is different from that of a magnet material made of, for example, Sm-Co. Therefore, the thermal expansion is performed in the optical isolator module manufacturing stage and the optical isolator module usage stage. The transparent body may be destroyed or peeled off from the end face of the cylindrical magnet due to the difference in the coefficients. The invention according to claim 3 relates to an invention for avoiding such a problem.
[0023]
That is, the invention according to claim 3
On the premise of the optical isolator module according to the invention of claim 1 or 2,
A window frame having a window portion continuous with a cylindrical portion of the cylindrical magnet in the cylindrical holder or the optical isolator is attached to the light incident side end surface of the ferrule via the cylindrical holder or the cylindrical magnet. The transparent body is attached to the light incident side of the frame body, and the window portion of the window frame body is closed.
[0024]
And according to the optical isolator module which concerns on invention of Claim 3,
Since the transparent body is attached via the window holder attached to the cylindrical holder or the cylindrical magnet instead of the structure in which the transparent body is directly bonded to the end face of the cylindrical magnet, the transparent body and its thermal expansion coefficient are By constructing the window frame body with an approximate material, it is possible to prevent the transparent body from being broken or peeled off due to the difference in thermal expansion coefficient in the optical isolator module manufacturing stage or the optical isolator module usage stage. It becomes possible.
[0025]
The invention according to claim 4 selects an optical glass having a refractive index of 1.5 for light having a wavelength of 1.55 μm as a constituent material of the transparent body, and has the same or substantially the same thermal expansion as the optical glass. The present invention relates to an invention that specifies an optical isolator module that includes the above-mentioned window frame body made of a material having a coefficient and reliably prevents the destruction and peeling phenomenon of a transparent body due to the difference in thermal expansion coefficient.
[0026]
That is, the invention according to claim 4
Based on the optical isolator module according to the invention of claim 3,
A stainless material in which the transparent body is made of optical glass having a refractive index of 1.5 with respect to light having a wavelength of 1.55 μm, and the window frame has the same or substantially the same thermal expansion coefficient as the optical glass; It is characterized by comprising a nickel-based alloy.
[0027]
Examples of the optical glass include BK6, BK7, and C3 (trade name, manufactured by HOYA). The thermal expansion coefficient of BK6 is 92 × 10. ^-7 / K, BK7 is 89 × 10 ^-7 / K, C3 is 103 × 10 ^-7 / K. As a stainless material having the same or substantially the same thermal expansion coefficient as these optical glasses, SUS410 (thermal expansion coefficient: 99 × 10 ^-7 / K), SUS430 (thermal expansion coefficient: 104 × 10 ^-7 / K), SUS436 (thermal expansion coefficient: 93 × 10 ^-7 / K), SUS440A (thermal expansion coefficient: 102 × 10 ^-7 / K) and SUS440C (thermal expansion coefficient: 102 × 10 ^-7 / K) and the like, and hastelloy (trade name, thermal expansion coefficient: 113 × 10) as a nickel-based alloy having the same or substantially the same thermal expansion coefficient as the optical glass. ^-7 / K), Inconel (thermal expansion coefficient: 115 × 10 ^-7 / K) and the like.
[0028]
Next, in the optical isolator module according to the third and fourth aspects of the present invention, an appropriate part of the window frame opposite to the light incident side (appropriate portion in the optical isolator module to which the cylindrical holder is applied) A cylindrical magnet that forms a part of the optical isolator is disposed in an appropriate portion on the side opposite to the light incident side of the window frame body), and the configuration of the window frame body to which the cylindrical magnet is attached When a magnetic material is applied as a material, a portion of the window frame body can be used as a magnet because a portion of the window frame body adjacent to the cylindrical magnet is magnetized. Applicable. The invention according to claim 5 relates to an invention made for such technical reasons.
[0029]
That is, the invention according to claim 5
Based on the optical isolator module according to the invention of claim 3,
The window frame is made of a magnetic material.
[0030]
Next, in the present invention, the transparent light entrance / exit surface of the transparent body having a wedge-shaped cross section is inclined in the same direction as the inclination direction of the optical fiber tip with respect to the optical axis of the optical fiber in the ferrule. Therefore, it is possible to prevent the recombination of the reflected LD light with respect to the semiconductor laser element without setting the inclination angle of the transparent body as large as about 20 degrees as described above, and the inclination angle is as described above. Since it is not necessary to set it as large as about 20 degrees, it is possible to prevent a decrease in LD optical coupling efficiency with respect to the optical fiber due to the aberration in the transparent body.
[0031]
In this case, the inclination angle (θ of the light incident surface in the transparent body depends on the inclination angle with respect to the optical axis of the light entrance / exit surface on the optical isolator side in the transparent body arranged obliquely and the numerical aperture of the condenser lens to be applied. ) In the range of 8 to 18 degrees, the above two effects (that is, the effect of preventing the recombination of the reflected LD light with respect to the semiconductor laser element and the effect of preventing the reduction of the coupling efficiency of the LD light with respect to the optical fiber) are made effective. It will be possible to demonstrate. The invention according to claim 6 is made for such technical reasons.
[0032]
That is, the invention according to claim 6
On the premise of the optical isolator module according to any one of claims 1 to 5,
The inclination angle (θ) of the light incident surface in the transparent body is set in the range of 8 degrees to 18 degrees.
[0033]
Next, the invention which concerns on Claims 7-11 is related with the invention which specified the structure of the optical isolator component integrated in the optical isolator module which concerns on Claims 1-6.
[0034]
That is, the invention according to claim 7
On the premise of an optical isolator component incorporated in the optical isolator module according to any one of claims 1 to 6,
A cylindrical magnet, a laminated body made of a polarizing plate glass, a Faraday rotator and a polarizing plate, which are fitted into the cylindrical portion of the magnet and integrated with an optical adhesive, and the cylindrical portion open surface on the light incident side of the magnet A cross-sectional wedge-shaped transparent body attached to an adjacent polarizing plate glass via an optical adhesive and having a gradient on the light incident side. Have It is characterized by
The invention according to claim 8 provides:
A window frame body having a window portion, a transparent body having a wedge-shaped cross section attached to the light incident side of the window frame body so as to close the window portion and having a gradient on the light incident side, and the light incidence of the window frame body A cylindrical magnet attached to the opposite side of the window so as not to close the window, and a polarizing plate glass, a Faraday rotator and a polarizing plate which are inserted into the cylindrical portion of the magnet and integrated with an optical adhesive And a laminate in which the transparent body and the polarizing plate glass adjacent thereto are bonded via an optical adhesive Have And a part of outer edge in the light-incidence side of a laminated body is engaged with the opening edge part of the window part in the said window frame, It is characterized by the above-mentioned.
[0035]
The inventions according to claim 9 and claim 10
Both are based on the optical isolator component according to the invention of claim 8,
The invention according to claim 9 is:
A stainless material in which the transparent body is made of optical glass having a refractive index of 1.5 with respect to light having a wavelength of 1.55 μm, and the window frame has the same or substantially the same thermal expansion coefficient as the optical glass; It is composed of a nickel-base alloy,
The invention according to claim 10 provides
The window frame is made of a magnetic material.
[0036]
Furthermore, the invention according to claim 11 is
Based on the optical isolator component according to claim 7, 8, 9 or 10,
The inclination angle (θ) of the light incident surface in the transparent body is set in the range of 8 degrees to 18 degrees.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0038]
As shown in FIGS. 1A to 1B, an optical isolator module 1 according to this embodiment is a ceramic capillary that holds the tip of an optical fiber 2 having a tip inclined at 13 degrees and having an inclined surface of 13 degrees. 3, a ferrule 4 made of stainless steel (SUS304) to which the optical fiber 2 whose tip is held by the capillary 3 is attached and having a flange portion 40, and a stainless steel material having a flange portion 50 and the ferrule 4 tip is inserted ( A stainless steel (SUS430 or SUS440C) window frame having a cylindrical holder 5 made of SUS304 and a window portion 60 attached to the light incident side end face of the cylindrical holder 5 and continuous with the cylindrical portion of the cylindrical holder 5. The body 6 is attached to the side wall surface of the cylindrical holder 5 of the window frame body 6, and the inner diameter of the cylindrical portion is set to be substantially the same as the size of the window 60. And an Sm—Co cylindrical magnet 70 that forms a part of the optical isolator 7, and is attached to the light incident side of the window frame 6 so as to close the window 60 of the window frame 6 and the optical fiber 2. It has a light incident surface tilted by 13 degrees in the direction opposite to the tilt direction of the tip, and its back surface (that is, the light entrance / exit surface on the optical isolator side) is the same as the tilt direction of the tip of the optical fiber 2 with respect to the optical axis of the optical fiber 2. A transparent body 8 made of optical glass (BK7) and obliquely arranged so as to be inclined by 3 degrees in the direction is bonded to the back side of the transparent body 8 via an optical adhesive (epoxy adhesive) 9. A polarizing plate glass (polarizer) 71, a RIG Faraday rotator 72, a polarizing plate glass (polarizer) 73 that forms part of the optical isolator 7, and a stainless steel material attached to the light incident side wall surface of the window frame 6 (S S304) The guard ring 10 of the transparent body 8 formed of a cylindrical body made up of the main part thereof, and the polarizing plate glass (polarizer) 71, RIG Faraday rotator 72, polarizing plate glass (polarizer) 73 Each of the light incident / exit surfaces is also inclined with respect to the optical axis of the optical fiber 2 by being inclined by 3 degrees in the same direction as the inclination direction of the tip of the optical fiber 2. RIG is an abbreviation for magnetic garnet (rare earth-iron garnet).
[0039]
The optical isolator module 1 is manufactured according to the following assembly procedure.
[0040]
First, as shown in FIG. 2, the transparent body 8 that has been metallized in advance is a rectangular fitting recess provided around the window 60 in the window frame 6 (the depth of the bottom of this recess is shown in FIG. 2). The upper surface of the window frame body 6 is fixed to the window frame body 6 with Au-Sn solder, and then the surface of the window frame body 6 to which the transparent body 8 is attached. The guard ring of the transparent body 8 is welded to the side by electric welding. The transparent body 8 is arranged obliquely by fitting the transparent body 8 into the fitting recess 61.
[0041]
Next, polarizing plate glass (polarizer) 71, RIG Faraday rotator 72 and polarizing plate glass integrated with an optical adhesive from the side opposite to the surface on which the transparent body 8 is attached to the window frame 6. (Polarizer) 73 having a rectangular cross section (referred to as PFRP) is disposed so that the lower outer edge on the tip side engages the opening edge 62 of the window 60 in the window frame 6, and After the laminated polarizing plate glass (polarizer) 71 is bonded and fixed to the transparent body 8 using a transparent epoxy adhesive, the cylindrical magnet 70 is fixed to the wall surface of the window frame 6 with an adhesive.
[0042]
Next, the joint of the window frame 6 and the cylindrical holder 5 is welded over the entire circumference by an electric welding method. The window frame 6 and the cylindrical holder 5 are welded over the entire circumference when the optical isolator module 1 according to this embodiment is connected to a semiconductor laser module (not shown). It is for realizing.
[0043]
Finally, the capillary 3 located at the tip of the ferrule 4 to which the optical fiber 2 is attached is fitted into the cylindrical holder 5, and after alignment (positioning), the joining site is YAG laser welded according to the embodiment. The optical isolator module 1 is obtained.
[0044]
In the alignment of the optical fiber 2, the adjustment for aligning the condensing point of the LD light by the condensing lens with the tip of the optical fiber 2 (that is, the alignment of the optical fiber 2 in the optical axis direction) is performed as described above. Adjustment is unnecessary by adjusting the distance from the flange 40 of the ferrule 4 to the tip of the optical fiber 2 in advance. Further, in FIG. 1, alignment in the vertical direction of the paper surface (that is, the direction perpendicular to the optical axis direction) and the direction perpendicular to the paper surface is also performed at the fitting portion of the cylindrical holder 5 and the ferrule 4. If the outer diameter of the ferrule 4 is matched, adjustment is not necessary.
[0045]
However, the rotational alignment about the optical axis of the optical fiber 2 is an essential adjustment item because the tip of the optical fiber 2 is inclined in the present invention.
[0046]
When a general single mode fiber is applied as the optical fiber 2, the optical fiber 2 is coupled with the LD light coupled to the tip of the optical fiber 2 by the condenser lens and the optical fiber 2 is rotated. What is necessary is just to align to the position where the light quantity couple | bonded with is the maximum.
[0047]
When a polarization maintaining fiber is used as the optical fiber 2, first, the direction of the polarization axis in the optical fiber 2 coincides with the polarization direction of the optical fiber side polarizing glass (polarizer) 73 in the optical isolator 7. In such a state, the inclined surface at the tip of the optical fiber 2 is polished so as to be inclined in the direction opposite to the inclined direction of the light incident surface in the transparent body 8. Then, the polarization extinction ratio at the end of the optical fiber (the other end) of the LD light coupled to the optical fiber 2 while rotating the optical fiber 2 is maximized by coupling the LD light to the tip of the optical fiber 2 by the condenser lens. You just need to align it.
[0048]
The optical isolator module 1 according to the embodiment manufactured as described above is incorporated in the semiconductor laser module including the semiconductor laser element (LD) and the condenser lens to constitute the above-described optoelectronic device.
[0049]
According to the optical isolator module 1 according to the embodiment, each light incident / exit surface of the optical isolator 7 and the optical isolator side light incident / exit surface of the transparent body 8 are relative to the optical axis of the optical fiber 2 in the ferrule 4. Since the optical isolator 7 and the transparent body 8 are obliquely arranged so as to be inclined by 3 degrees in the same direction as the tip direction of the optical fiber 2, the back surface of the transparent body 8 is shown in the ray tracing diagram of FIG. The reflected LD light reflected on the side does not return to the condenser lens 11 or the semiconductor laser element (LD) 12 side, and each component surface of the optical isolator 7 having an interface parallel to the back surface of the transparent body 8 (that is, The reflected LD light reflected by the polarizer 71, the RIG Faraday rotator 72, and the light entrance / exit surfaces of the polarizer 73) does not return to the condenser lens 11 or the LD 12 side, and the ray tracing shown in FIG. Reflected LD light reflected by the surface side of the transparent member 8 as shown in FIG. (I.e. LD12 side surface of the transparent body 8), as it is conventional not return to the LD12 side. Accordingly, there is an advantage that the recombination of the reflected LD light with respect to the LD 12 can be surely prevented.
[0050]
In this optical isolator module 1, the end face of the optical fiber 2 is inclined because the wedge-shaped transparent body 8 having a light incident surface inclined by 13 degrees in the direction opposite to the inclination direction of the tip of the optical fiber 2 is applied. This has the advantage that the coupling efficiency of the LD light with respect to the optical fiber 2 does not decrease despite the fact that the surface is constituted.
[0051]
Further, the transparent body 8 made of optical glass (BK7) is fixed to the window frame body 6 made of stainless steel (SUS430 or SUS440C) with Au—Sn solder. Accordingly, since the difference in thermal expansion coefficient between the transparent body 8 and the Sm—Co cylindrical magnet 70 is directly fixed to the Sm—Co cylindrical magnet 70, the thermal isolator module is manufactured at the optical isolator module manufacturing stage or the optical isolator module usage stage. There is also an advantage that the transparent body 8 is not broken or peeled off from the end face of the cylindrical magnet 70 due to the difference in expansion coefficient.
[0052]
A refractive index of 1.5 is provided between a polarizing plate glass (polarizer) 71 having a refractive index of 1.5 and a transparent body 8 made of optical glass having a refractive index of 1.5 (BK7) forming a part of the optical isolator. Since the optical isolator 7 and the transparent body 8 are integrated by interposing an epoxy adhesive, light reflection at the interface between the polarizing plate glass (polarizer) 71 and the transparent body 8 is reduced, and reflection to the LD 12 is performed. This has the advantage that LD light recombination can be prevented more reliably and the assembly work of the optical isolator module can be simplified.
[0053]
In this embodiment, the optical isolator component incorporated in the optical isolator module includes the window frame body 6 having the window portion 60 and the cylinder attached to the side wall surface opposite to the light incident side of the window frame body 6. The transparent body 8 having a wedge-shaped cross section attached to the light incident side of the window frame body 6 so as to close the window portion 60, and the optical adhesive 9 on the back side of the transparent body 8 A laminated body composed of a polarizing plate glass (polarizer) 71, a RIG Faraday rotator 72, and a polarizing plate glass (polarizer) 73, and a transparent body 8 attached to the light incident side wall surface of the window frame body 6. Guard ring 10 Have ing.
[0054]
Next, FIG. 4 is an explanatory view showing a schematic configuration of an optical isolator module according to another embodiment.
[0055]
That is, the optical isolator module 1 according to this embodiment is equipped with the optical fiber 2 having the tip held by the capillary 3 and having the same inclined surface (inclination angle 13 degrees) as the capillary 3 and the collar 40. Sm-Co cylinder having a ferrule 4 and a polarizing glass (polarizer) 71, a RIG Faraday rotator 72, and a polarizing glass (polarizer) 73 mounted on the light incident side of the ferrule 4 and disposed in the cylindrical portion thereof A glass-shaped cross section having a light-incident surface that is attached to the light incident side of the cylindrical magnet 70 and closes the cylindrical portion and is inclined at the same angle in the direction opposite to the inclination direction of the tip of the optical fiber 2. Transparent body 8 and Have In addition, for the optical isolator 7 and the transparent body 8, each component surface of the optical isolator 7 (that is, each component surface of the polarizer 71, the RIG Faraday rotator 72, and the polarizer 73) and the light input on the optical isolator side of the transparent body 8. The exit surface is obliquely arranged so as to be inclined by 3 degrees with respect to the optical axis of the optical fiber 2 in the ferrule 4 in the same direction as the inclination direction of the tip of the optical fiber 2.
[0056]
In the optical isolator module 1 according to this embodiment, the optical isolator 7 and the transparent body 8 are configured such that each component surface of the optical isolator 7 and the optical input / output surface on the optical isolator side of the transparent body 8 are within the ferrule 4. The optical fiber 2 has an advantage that it can be surely prevented from recombination of the reflected LD light with respect to the LD because it is arranged obliquely so as to incline 3 degrees in the same direction as the inclination direction of the tip of the optical fiber 2. Since the transparent body 8 having a wedge-shaped cross section having a light incident surface inclined by 13 degrees in the direction opposite to the inclination direction of the tip of the optical fiber 2 is applied, light is emitted even though the end surface of the optical fiber 2 forms an inclined surface. There is an advantage that the coupling efficiency of the LD light to the fiber 2 is not lowered.
[0057]
In this embodiment, the optical isolator component incorporated in the optical isolator module includes an Sm—Co cylindrical magnet 70, a polarizing plate glass (polarizer) 71, a RIG Faraday rotator 72, a polarizing plate disposed in the cylindrical portion. A laminated body made of plate glass (polarizer) 73, and the transparent body 8 made of glass with a wedge-shaped cross section attached to the light incident side of the cylindrical magnet 70; Have ing.
[0058]
【The invention's effect】
According to the optical isolator module according to the invention of claim 1,
Since the transparent body is made of a transparent material having a wedge-shaped cross section having a light incident surface inclined in a direction opposite to the inclination direction of the tip of the optical fiber, it is possible to prevent a reduction in coupling efficiency of LD light to the optical fiber. And the optical isolator so that the light entrance / exit surfaces of the optical isolator and the light entrance / exit surface of the transparent optical isolator side are inclined in the same direction as the inclination direction of the optical fiber tip with respect to the optical axis of the optical fiber in the ferrule. Since the transparent body is obliquely disposed, the optical axis direction until the transparent body is incident on the transparent body having a wedge-shaped cross section is the optical axis direction of the optical fiber without setting the inclination angle of the transparent body as large as about 20 degrees, for example. This has the effect of preventing the recombination of the reflected LD light with respect to the semiconductor laser element set parallel or substantially parallel.
[0059]
According to the optical isolator module according to the invention of claim 2,
Since the polarizer of the optical isolator and the transparent body are bonded and integrated through an optical adhesive, the optical isolator module can be easily assembled.
[0060]
According to the optical isolator module according to the invention of claim 3,
Since the transparent body is attached through the window frame attached to the cylindrical holder or the cylindrical magnet instead of the structure in which the transparent body is directly bonded to the end face of the cylindrical magnet, the transparent body and its thermal expansion coefficient are approximate. By constructing the window frame body with the above-mentioned material, it is possible to prevent the transparent body from being broken or peeled off due to the difference in thermal expansion coefficient in the manufacturing stage of the optical isolator module or the usage stage of the optical isolator module. Have.
[0061]
Similarly, according to the optical isolator module according to the invention of claim 4,
A stainless material in which the transparent body is made of optical glass having a refractive index of 1.5 with respect to light having a wavelength of 1.55 μm, and the window frame has the same or substantially the same thermal expansion coefficient as the optical glass; Since it is composed of a nickel-based alloy, it has the effect of preventing the destruction and peeling of the transparent body due to the difference in the thermal expansion coefficient in the manufacturing stage of the optical isolator module and the usage stage of the optical isolator module. .
[0062]
Next, according to the optical isolator module according to the invention of claim 5,
Since the window frame body is made of a magnetic material and a portion of the window frame body adjacent to the cylindrical magnet is magnetized, a part of the window frame body can be used as a magnet. It has the effect that a magnet can be applied.
[0063]
According to the optical isolator module of the invention described in claim 6,
Since the tilt angle (θ) of the light incident surface in the transparent body is set in the range of 8 degrees to 18 degrees, it is possible to effectively prevent recombination of the reflected LD light with respect to the semiconductor laser element, and This has the effect of effectively preventing a decrease in the coupling efficiency of the LD light to the optical fiber.
[0064]
Next, according to the optical isolator component according to the invention of claims 7 to 11,
By incorporating the optical isolator module into the optical isolator module, the optical isolator module according to any one of claims 1 to 6 can be reliably configured.
[Brief description of the drawings]
FIG. 1A is a schematic configuration diagram of an optical isolator module according to an embodiment of the present invention, and FIG. 1B is a front view of the optical isolator module as viewed from the light incident side.
FIG. 2 is an exploded perspective view of an optical isolator component incorporated in the optical isolator module according to the embodiment.
FIGS. 3A and 3B are ray tracing diagrams showing the action of the cross-sectional wedge-shaped transparent body in the optical isolator module according to the embodiment. FIGS.
FIG. 4 is a schematic configuration explanatory diagram of an optical isolator module according to another embodiment.
FIG. 5 is an explanatory diagram showing a schematic configuration and operation of an optical isolator module according to a conventional example.
FIGS. 6A and 6B are ray tracing diagrams showing the action of a cross-sectional wedge-shaped transparent body in an optical isolator module according to a conventional example.
FIG. 7 is a schematic configuration explanatory diagram of an optical isolator module according to a conventional modification.
[Explanation of symbols]
1 Optical isolator module
2 Optical fiber
4 Ferrule
7 Optical isolator
8 Transparent body

Claims (11)

A ferrule equipped with an optical fiber whose tip is inclined, an optical isolator disposed on the light incident side of the ferrule, and a transparent body disposed on the light incident side of the optical isolator, and is emitted from the semiconductor laser element and In the optical isolator module that allows the laser light collected by the condenser lens to pass through the transparent body and the optical isolator and enter the tip of the optical fiber,
The transparent body is made of a transparent material having a wedge-shaped cross section having a light incident surface inclined in a direction opposite to the inclination direction of the tip of the optical fiber, and each light incident / exit surface of the optical isolator and the light input on the optical isolator side of the transparent body are formed. An optical isolator module characterized in that the optical isolator and the transparent body are arranged obliquely so that the emission surface is inclined in the same direction as the inclination direction of the optical fiber tip with respect to the optical axis of the optical fiber in the ferrule.   The optical isolator module according to claim 1, wherein the polarizer of the optical isolator and the transparent body are bonded via an optical adhesive.   A window frame having a window portion continuous with a cylindrical portion of the cylindrical magnet in the cylindrical holder or the optical isolator is attached to the light incident side end surface of the ferrule via the cylindrical holder or the cylindrical magnet. 3. The optical isolator module according to claim 1, wherein the transparent body is attached to the light incident side of the frame body and the window portion of the window frame body is closed.   A stainless material in which the transparent body is made of optical glass having a refractive index of 1.5 with respect to light having a wavelength of 1.55 μm, and the window frame has the same or substantially the same thermal expansion coefficient as the optical glass; 4. The optical isolator module according to claim 3, wherein the optical isolator module is made of a nickel-based alloy.   4. The optical isolator module according to claim 3, wherein the window frame is made of a magnetic material.   6. The optical isolator module according to claim 1, wherein an inclination angle (θ) of a light incident surface of the transparent body is set in a range of 8 degrees to 18 degrees. In the optical isolator component assembled in the optical isolator module according to claim 1,
A cylindrical magnet, a laminated body made of a polarizing plate glass, a Faraday rotator and a polarizing plate, which are fitted into the cylindrical portion of the magnet and integrated with an optical adhesive, and the cylindrical portion open surface on the light incident side of the magnet An optical isolator component comprising: a transparent body having a wedge-shaped cross section attached to an adjacent polarizing plate glass with an optical adhesive and having a gradient on the light incident side. In the optical isolator component assembled in the optical isolator module according to claim 1,
A window frame body having a window portion, a transparent body having a wedge-shaped cross section attached to the light incident side of the window frame body so as to close the window portion and having a gradient on the light incident side, and the light incidence of the window frame body A cylindrical magnet attached to the opposite side of the window so as not to close the window, and a polarizing plate glass, a Faraday rotator and a polarizing plate which are inserted into the cylindrical portion of the magnet and integrated with an optical adhesive from made and the polarizing plate glass adjacent thereto and the transparent body and a laminate which is bonded via an optical adhesive, and the window portion of the outer edge of the light incident side of the laminate in the window frame member An optical isolator component that is engaged with an opening edge of a portion.   A stainless material in which the transparent body is made of optical glass having a refractive index of 1.5 with respect to light having a wavelength of 1.55 μm, and the window frame has the same or substantially the same thermal expansion coefficient as the optical glass; 9. The optical isolator component according to claim 8, wherein the optical isolator component is made of a nickel-based alloy.   9. The optical isolator component according to claim 8, wherein the window frame is made of a magnetic material.   11. The optical isolator component according to claim 7, wherein an inclination angle (θ) of a light incident surface of the transparent body is set in a range of 8 degrees to 18 degrees.

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