U.S. patent application number 16/140815 was filed with the patent office on 2019-01-31 for optical module and method for manufacturing the optical module.
The applicant listed for this patent is Oclaro Japan, Inc.. Invention is credited to Takanori SUZUKI.
Application Number | 20190033539 16/140815 |
Document ID | / |
Family ID | 58690556 |
Filed Date | 2019-01-31 |
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United States Patent
Application |
20190033539 |
Kind Code |
A1 |
SUZUKI; Takanori |
January 31, 2019 |
OPTICAL MODULE AND METHOD FOR MANUFACTURING THE OPTICAL MODULE
Abstract
An optical module includes: a photonic device emitting or
receiving a light wave; an optical waveguide for transmitting the
light wave; a lens focusing the light wave; a mirror for changing a
traveling direction of the light wave to optically couple the
photonic device with the optical waveguide; a manipulation lever
for manipulating an orientation of the mirror; a support spring for
supporting the mirror; and a substrate integrated with the mirror,
the manipulation lever, and the support spring. The support spring
couples the mirror with the substrate so as to allow the mirror to
change the orientation thereof with movement or rotation along at
least two axes. The manipulation lever extends from the mirror in a
direction in which the manipulation lever avoids approaching the
optical waveguide.
Inventors: |
SUZUKI; Takanori; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Oclaro Japan, Inc. |
Sagamihara |
|
JP |
|
|
Family ID: |
58690556 |
Appl. No.: |
16/140815 |
Filed: |
September 25, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15351479 |
Nov 15, 2016 |
10101546 |
|
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16140815 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 6/422 20130101;
G02B 6/4238 20130101; G02B 26/0816 20130101; G02B 6/4249 20130101;
G02B 6/4244 20130101; G02B 6/4214 20130101; G02B 6/4206 20130101;
G02B 6/32 20130101; G02B 6/3512 20130101 |
International
Class: |
G02B 6/42 20060101
G02B006/42; G02B 26/08 20060101 G02B026/08; G02B 6/32 20060101
G02B006/32; G02B 6/35 20060101 G02B006/35 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 18, 2015 |
JP |
2015-225718 |
Claims
1. An optical module comprising: a photonic device emitting or
receiving a light wave; an optical waveguide transmitting the light
wave; a lens focusing the light wave; a mirror changing a traveling
direction of the light wave to optically couple the photonic device
with the optical waveguide; a manipulation lever manipulating an
orientation of the mirror; a support spring supporting the mirror;
and a substrate integrated with the mirror, the manipulation lever,
and the support spring, the substrate having a surface just over
which the mirror, the manipulation lever, and the support spring
are arranged, wherein: the mirror includes a mirror surface
reflecting the light wave, the mirror surface being directed
obliquely upward so that a first optical path between the mirror
surface and the optical waveguide does not overlap a second optical
path between the mirror surface and the photonic device, and the
second optical path extends in a direction which crosses the
surface of the substrate, the support spring couples the mirror
with the substrate so as to allow the mirror to change the
orientation thereof with movement or rotation along at least two
axes, and the manipulation lever extends from the mirror in a
direction in which the manipulation lever avoids approaching the
optical waveguide.
2. The optical module according to claim 1, wherein: the support
spring extends in a direction different from the direction of the
manipulation lever.
3. The optical module according to claim 2, wherein: a plurality of
the support springs are provided to extend in directions different
from each other.
4. The optical module according to claim 1, wherein: the
manipulation lever is bent to connect to the mirror, and extends
along the support spring.
5. The optical module according to claim 1, wherein: the
manipulation lever is brazed to the substrate.
6. The optical module according to claim 5, further comprising: an
electrode provided adjacent to the manipulation lever on the
substrate and causing a brazing material to melt.
7. The optical module according to claim 1, wherein: the substrate
is an SOI substrate, and the mirror, the manipulation lever, and
the support spring are integrally formed in a surface Si layer of
the SOI substrate.
8. The optical module according to claim 1, wherein: the lens is
formed integrally with the photonic device.
9. The optical module according to claim 1, wherein: the photonic
device is an array photonic device, which emits or receives each of
a plurality of light waves, and the optical waveguide transmits the
plurality of light waves.
10. The optical module according to claim 1, further comprising: an
optical isolator between the mirror and the optical waveguide.
11. The optical module according to claim 1, wherein: the photonic
device is a semiconductor laser device.
12. The optical module according to claim 1, wherein: the photonic
device is a semiconductor light-receiving device.
13. The optical module according to claim 1, wherein: the
manipulation lever has a handle, and the mirror, the photonic
device, and the handle are aligned in a row, when viewed from above
the surface of the substrate.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority from Japanese
application JP 2015-225718, filed on Nov. 18, 2015, the content of
which is hereby incorporated by reference into this
application.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to an optical module and a
method for manufacturing the optical module.
2. Description of the Related Art
[0003] For improving the transmission speed and transmission
capacity of optical communications, techniques for transmitting a
plurality of optical signals in parallel have been studied. An
optical module that performs parallel transmission may include
optical axis adjustment mechanisms that individually adjust the
optical axes of the optical signals.
[0004] JP 2013-231937 A discloses a method for manufacturing an
optical device including the step of plastically deforming a first
member and a second member by irradiation with laser light to
thereby adjust the position of an optical element.
[0005] JP 2012-517028 T discloses an optical assembly including a
movable lever that holds a lens focusing the light of a first
waveguide into a second waveguide.
[0006] U.S. Patent Application Publication No. 2015/0078707
discloses a device including an adjustment mechanism with a
micro-electro-mechanical-system (MEMS) lever including flexures and
provided with a lens.
SUMMARY OF THE INVENTION
[0007] The optical module including the optical axis adjustment
mechanisms individually adjusting the optical axes of the plurality
of optical signals may increase in size according to an increase in
the number of channels of the optical signals to be transmitted. In
this case, when the optical axis adjustment mechanism is downsized
for downsizing the module, the adjustable range may be limited, or
advanced control may be needed for manipulating a micro
mechanism.
[0008] Therefore, it is an object of the invention to provide an
optical module capable of being downsized while favorably retaining
the adjustable range and operability of an optical axis adjustment
mechanism, and a method for manufacturing the optical module.
[0009] (1) For solving the above problem, an optical module
according to an aspect of the invention includes: a photonic device
emitting or receiving a light wave; an optical waveguide for
transmitting the light wave; a lens focusing the light wave; a
mirror for changing a traveling direction of the light wave to
optically couple the photonic device with the optical waveguide; a
manipulation lever for manipulating an orientation of the mirror; a
support spring for supporting the mirror; and a substrate
integrated with the mirror, the manipulation lever, and the support
spring, wherein the mirror includes a mirror surface reflecting the
light wave, the mirror surface being directed obliquely upward so
that a first optical path between the mirror surface and the
optical waveguide does not overlap a second optical path between
the mirror surface and the photonic device, the support spring
couples the mirror with the substrate so as to allow the mirror to
change the orientation thereof with movement or rotation along at
least two axes, and the manipulation lever extends from the mirror
in a direction in which the manipulation lever avoids approaching
the optical waveguide.
[0010] (2) The optical module according to (1), wherein the support
spring extends in a direction different from the manipulation
lever.
[0011] (3) The optical module according to (2), wherein a plurality
of the support springs are provided to extend in directions
different from each other.
[0012] (4) The optical module according to (1), wherein the
manipulation lever is bent to connect to the mirror, and extends
along the support spring.
[0013] (5) The optical module according to (1), wherein the
manipulation lever is brazed to the substrate.
[0014] (6) The optical module according to (5), further including
an electrode provided adjacent to the manipulation lever on the
substrate and causing a brazing material to melt.
[0015] (7) The optical module according to (1), wherein the
substrate is an SOI substrate, and the mirror, the manipulation
lever, and the support spring are integrally formed in a surface Si
layer of the SOI substrate.
[0016] (8) The optical module according to (1), wherein the lens is
formed integrally with the photonic device.
[0017] (9) The optical module according to (1), wherein the
photonic device is an array photonic device, which emits or
receives each of a plurality of light waves, and the optical
waveguide transmits each of the plurality of light waves.
[0018] (10) The optical module according to (1), further including
an optical isolator between the mirror and the optical
waveguide.
[0019] (11) The optical module according to (1), wherein the
photonic device is a semiconductor laser device.
[0020] (12) The optical module according to (1), wherein the
photonic device is a semiconductor light-receiving device.
[0021] (13) For solving the above problem, a method for
manufacturing an optical module according to another aspect of the
invention includes: a step of providing, to a substrate, a photonic
device emitting or receiving a light wave, an optical waveguide for
transmitting the light wave, and a lens focusing the light wave; a
step of integrally forming, in the substrate, a mirror changing a
traveling direction of the light wave to optically couple the
photonic device with the optical waveguide, the mirror including a
mirror surface reflecting the light wave, the mirror surface being
directed obliquely upward so that a first optical path between the
mirror surface and the optical waveguide does not overlap a second
optical path between the mirror surface and the photonic device, a
manipulation lever manipulating an orientation of the mirror and
extending from the mirror in a direction in which the manipulation
lever avoids approaching the optical waveguide, and a support
spring supporting the mirror and coupling the mirror with the
substrate so as to allow the mirror to change the orientation
thereof with movement or rotation along at least two axes; and an
adjustment step of manipulating the orientation of the mirror with
the manipulation lever to adjust the traveling direction of the
light wave reflected by the mirror.
[0022] (14) The method for manufacturing the optical module
according to (13), further including, after the adjustment by the
adjustment step, a brazing step of flowing a brazing material
between the manipulation lever and the substrate and brazing the
manipulation lever to the substrate.
[0023] (15) The method for manufacturing the optical module
according to (13), wherein in the adjustment step, the orientation
of the mirror is manipulated by applying an external force to a
handle of the manipulation lever located on the side opposite to
the optical waveguide with respect to a position where the mirror
is disposed.
[0024] According to the invention, the optical module capable of
being downsized while favorably retaining the adjustable range and
operability of an optical axis adjustment mechanism, and the method
for manufacturing the optical module are provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a side view showing an optical module according to
an embodiment of the invention.
[0026] FIG. 2 is a top view showing the optical module according to
the embodiment of the invention.
[0027] FIG. 3 is a top view showing an adjustment step in a method
for manufacturing the optical module according to the embodiment of
the invention.
[0028] FIG. 4 is a top view showing an optical axis adjustment
mechanism of an optical module according to a first modified
example of the embodiment of the invention.
[0029] FIG. 5 is a top view showing an optical axis adjustment
mechanism of an optical module according to a second modified
example of the embodiment of the invention.
[0030] FIG. 6 is a top view showing an optical axis adjustment
mechanism of an optical module according to a third modified
example of the embodiment of the invention.
[0031] FIG. 7 is a side view showing an optical module according to
a fourth modified example of the embodiment of the invention.
[0032] FIG. 8 is a side view showing an optical module according to
another embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Hereinafter, embodiments of the invention will be
specifically described in detail based on the drawings. Throughout
the drawings for illustrating the embodiments, members having the
same function are denoted by the same reference numeral and sign,
and the repetitive description thereof is omitted. The drawings
shown below are merely illustrative of examples of the embodiments,
and the size of the drawing does not necessarily coincide with the
scale described in the examples.
[0034] FIG. 1 is a side view showing an optical module 1 according
to an embodiment of the invention. FIG. 1 represents the y-z plane,
and the x-axis is an axis that penetrates the paper surface and is
directed toward the front side. FIG. 2 is a top view showing the
optical module 1 according to the embodiment of the invention. FIG.
2 represents the x-z plane, and the y-axis is an axis that
penetrates the paper surface and is directed toward the front side.
In FIG. 2, an array-type semiconductor laser device 20 is not
illustrated for clarity of description. The optical module 1
according to the embodiment includes a first optical axis
adjustment mechanism A, a second optical axis adjustment mechanism
B, a third optical axis adjustment mechanism C, and a fourth
optical axis adjustment mechanism D as optical axis adjustment
mechanisms each including a mirror 12, a manipulation lever 11, and
support springs 13. In the optical module 1 according to the
embodiment, the array pitch (pitch in the x-axis direction between
laser light incident on the first optical axis adjustment mechanism
A and laser light incident on the second optical axis adjustment
mechanism B) is 250 .mu.m.
[0035] The optical module 1 includes the array-type semiconductor
laser device 20 as a photonic device, a silicon-on-insulator (SOI)
substrate 10, and optical waveguides 30. The array-type
semiconductor laser device 20 is a photonic device that emits
(sends) a plurality of light waves, and is specifically an array
photonic device that oscillates four laser lights. The array-type
semiconductor laser device 20 includes optical resonators 21 that
oscillate the laser lights, mirror surfaces 22 that reflect the
laser lights downward, and lenses 23 that focus the laser lights.
The lens 23 is a lens that focuses the light wave, and formed
integrally with the array-type semiconductor laser device 20. Since
the lens 23 is formed integrally with the array-type semiconductor
laser device 20, the optical module 1 is further downsized.
[0036] The SOI substrate 10 is a substrate including an insulating
layer (SiO.sub.2 layer) and a surface Si layer successively stacked
on a Si substrate. The SOI substrate 10 according to the embodiment
is integrated with the mirror 12, the manipulation lever 11, and
the support springs 13. The mirror 12 changes the traveling
direction of the light wave to optically couple the array-type
semiconductor laser device 20 with the optical waveguide 30. The
manipulation lever 11 is a lever that is provided to extend in the
z-axis direction to manipulate the orientation of the mirror 12.
The support springs 13 support the mirror 12. The mirror 12, the
manipulation lever 11, and the support springs 13 are formed in a
suspended state inside the SOI substrate 10, and the support
springs 13 support the whole of them. The support springs 13 are
provided to extend in the x-axis direction, and are not shown in
FIG. 1.
[0037] The laser light reflected by the mirror 12 is incident on
the optical waveguide 30. The optical waveguide 30 transmits the
light wave. In the optical module 1 according to the embodiment,
the photonic device is an array photonic device, which sends each
of the plurality of light waves. Moreover, the optical waveguides
30 transmit the plurality of light waves. The photonic device and
the optical waveguides 30 are formed into array forms, so that the
optical module 1 can be downsized.
[0038] As shown in FIG. 1, the mirror 12 includes a mirror surface
that reflects the light wave. The mirror surface is directed
obliquely upward so that a first optical path between the mirror
surface and the optical waveguide 30 does not overlap a second
optical path between the mirror surface and the array-type
semiconductor laser device 20. With this configuration, the laser
light that is emitted from the array-type semiconductor laser
device 20 in the negative direction with respect to the y-axis is
reflected in the positive direction with respect to the z-axis and
incident on the optical waveguide 30. It is easy to downsize the
mirror 12. Therefore, by providing the mirror 12 at the tip of the
manipulation lever 11, the optical axis adjustment mechanism can be
downsized compared with the case where another optical component
such as a ball lens is provided on the manipulation lever 11, and
thus the optical module 1 can be downsized. Moreover, the distance
between the mirror 12 and the optical waveguide 30 can be
shortened, and thus the optical module 1 can be downsized. The
mirror surface of the mirror 12 according to the embodiment is a
plane whose normal direction falls in the y-z plane; however, the
mirror surface may be a curved surface or a plane whose normal
direction is out of the y-z plane.
[0039] The support springs 13 couple the mirror 12 with the SOI
substrate 10 so as to allow the mirror 12 to change the orientation
thereof with movement or rotation along at least two axes.
[0040] Specifically, the support springs 13 are provided so that
the mirror 12 can move along the x-axis, the y-axis, and the
z-axis. Moreover, the support springs 13 are provided so that the
mirror 12 can rotate about the x-axis, the y-axis, and the z-axis.
Since the mirror 12 can change the orientation thereof with
movement or rotation along at least two axes as described above,
the optical axis can be adjusted so that the laser light is coupled
to the optical waveguide 30. Moreover, since the optical axis
adjustment mechanisms are independently provided for each of the
laser lights, optical coupling can be optimized for all of the
optical waveguides 30. The support spring 13 according to the
embodiment is elastically deformable, but may be plastically
deformable. Moreover, by adjusting the number of steps or the width
of the support spring 13, the magnitude of an external force
necessary for displacing the mirror 12 and the force for holding
the mirror 12 can be appropriately adjusted.
[0041] The manipulation lever 11 extends from the mirror 12 in a
direction in which the manipulation lever 11 avoids approaching the
optical waveguide 30. Specifically, the manipulation lever 11
extends in the negative direction with respect to the z-axis. In
other words, the manipulation lever 11 extends in the same
direction as the extending direction of the optical waveguide 30.
Since the manipulation lever 11 extends in the direction in which
the manipulation lever 11 avoids approaching the optical waveguide
30, the movable range of the manipulation lever 11 is widely
ensured, and the manipulation lever 11 can be manipulated at a
position not interfering with the array-type semiconductor laser
device 20 or the like. Therefore, the adjustable range and
operability of the optical axis adjustment mechanism become
favorable.
[0042] In the optical module 1 according to the embodiment, the
manipulation lever 11 is brazed to the SOI substrate 10 with a
brazing material 15. The manipulation lever 11 included in the
second optical axis adjustment mechanism B is brazed to the SOI
substrate 10 in the state where the manipulation lever 11 is
displaced in the negative direction with respect to the x-axis. The
manipulation lever 11 included in the fourth optical axis
adjustment mechanism D is brazed to the SOI substrate 10 in the
state where the manipulation lever 11 is displaced in the positive
direction with respect to the x-axis. By brazing the manipulation
lever 11 in the state of being displaced as described above, the
optical module 1 can be shipped in the state where the optical
coupling with the optical waveguide 30 is reliably obtained.
Wettability may be improved by depositing a metal film of gold or
the like on a portion of the manipulation lever 11 to be brazed to
the SOI substrate 10.
[0043] The optical module 1 according to the embodiment further
includes electrodes 14 that are provided adjacent to the
manipulation lever 11 on the SOI substrate 10 and cause the brazing
material to melt. The electrode 14 generates heat due to an
electric current flowing therethrough in response to an applied
voltage, and causes the brazing material 15 to melt. In the example
shown in FIG. 2, the brazing material 15 is left unmelted on the
electrode 14 in the second optical axis adjustment mechanism B and
the fourth optical axis adjustment mechanism D. When the
manipulation lever 11 is displaced and brazed to the SOI substrate
10, brazing may be sufficiently performed only with the brazing
material 15 on one side as in the second optical axis adjustment
mechanism B or the fourth optical axis adjustment mechanism D, and
thus the brazing material 15 not used for fixation may be left on
the electrode 14. Since the brazing material 15 is melted using the
electrode 14 as described above, the step of flowing the brazing
material into a micro area can be easily carried out, and thus the
fixation of the manipulation lever 11 is relatively easily
performed. In the optical module 1 according to the embodiment, the
brazing material 15 is previously prepared on all of the electrodes
14. However, the brazing material 15 may be placed on the electrode
14 when the manipulation lever 11 is brazed. In that case, the
manipulation lever 11 is displaced to a desired position, the
brazing material 15 is set on the electrode 14, an electric current
is caused to flow through the electrode 14 to melt the brazing
material 15, and the manipulation lever 11 is brazed. The
manipulation lever 11 may be fixed with a UV curable resin or
adhesive.
[0044] In the optical module 1 according to the embodiment, the
mirror 12, the manipulation lever 11, and the support springs 13
are integrally formed in the surface Si layer of the SOI substrate
10. The mirror 12, the manipulation lever 11, and the support
springs 13 are formed by etching the surface Si layer and the
insulating layer of the SOI substrate 10 to form an external shape,
and then dissolving only the insulating layer by etching. With the
step described above, the mirror 12, the manipulation lever 11, and
the support springs 13 in a suspended state are obtained. By
integrally forming the mirror 12, the manipulation lever 11, and
the support springs 13 in the surface Si layer of the SOI substrate
10, an optical axis adjustment mechanism that is very small and has
a wide movable range can be obtained, and thus the optical module
1, which has a wide optical axis adjustment range and is downsized,
is obtained.
[0045] The array-type semiconductor laser device 20 according to
the embodiment is of a type in which a laser including the optical
resonator 21 in a direction parallel to the SOI substrate 10
includes the mirror surface 22 allowing oscillation light to be
emitted in a direction vertical to the SOI substrate 10, but is not
limited to this type. For example, the so-called vertical cavity
surface emitting laser (VCSEL), which includes an optical resonator
in the direction vertical to the SOI substrate 10 and emits
oscillation light in the direction vertical to the SOI substrate
10, maybe used. Further, an edge-emitting laser, which includes an
optical resonator in the direction parallel to the SOI substrate 10
and emits oscillation light in the direction parallel to the SOI
substrate 10, may be used. When the edge-emitting laser is used, it
is preferable to employ the arrangement in which, for example, the
edge-emitting laser is disposed with its emitting face side facing
the SOI substrate 10 and a condensing lens is separately disposed
between the emitting face and the mirror 12. Moreover, the
array-type semiconductor laser device 20 according to the
embodiment oscillates laser light at a wavelength of approximately
1310 nm, but the wavelength of laser light may be within the 1.3
.mu.m band or 1.55 .mu.m band, which is generally used in optical
communications.
[0046] The mirror surface of the mirror 12 may be a 45.degree.
surface or surfaces, other than the 45.degree. surface, which are
obtained by subjecting the SOI substrate 10 to anisotropic wet
etching. In the case of silicon, a crystal plane inclined at an
angle of approximately 54.degree. can be formed by wet etching
using potassium hydroxide. In that case, when, for example, the
emitted light is tilted from the y-axis to the edge face side of
the optical resonator 21 by approximately 18.degree. , the optical
axis of light reflected by the mirror surface of the mirror 12 can
be made substantially parallel to the SOI substrate 10.
[0047] FIG. 3 is a top view showing an adjustment step in a method
for manufacturing the optical module 1 according to the embodiment
of the invention. In the method for manufacturing the optical
module 1 according to the embodiment, the step of integrally
forming the mirror 12, the manipulation lever 11, and the support
springs 13 in the SOI substrate 10 is first performed. Moreover,
separately from the step described above, the step of preparing the
photonic device (the array-type semiconductor laser device 20)
sending or receiving light waves, and the optical waveguides 30 for
transmitting the light waves is performed. The lens 23 condensing
the light wave is integrated and formed into the array-type
semiconductor laser device 20. However, the lens 23 is not limited
to this and may be prepared as another member. Next, these
components are assembled into the form shown in FIGS. 1 and 2. In
this case, the mirror 12 changes the traveling direction of the
light wave to optically couple the array-type semiconductor laser
device 20 with the optical waveguide 30, and includes the mirror
surface reflecting the light wave. The mirror surface is directed
obliquely upward so that the first optical path between the mirror
surface and the optical waveguide 30 does not overlap the second
optical path between the mirror surface and the array-type
semiconductor laser device 20. The manipulation lever 11
manipulates the orientation of the mirror 12, and extends from the
mirror 12 in the direction in which the manipulation lever 11
avoids approaching the optical waveguide 30. The support springs 13
support the mirror 12, and couple the mirror 12 with the SOI
substrate 10 so as to allow the mirror 12 to change the orientation
thereof with movement or rotation along at least two axes.
[0048] Next, the adjustment step is performed. The adjustment step
is the step of manipulating the orientation of the mirror 12 with
the manipulation lever 11 to adjust the traveling direction of the
light wave reflected by the mirror 12. In the example shown in FIG.
3, the orientation of the optical axis is rotated about the y-axis
by an angle .theta., and is changed from a first direction P1 to a
second direction P2. Even when the array-type semiconductor laser
device 20 or the optical waveguide 30 has an error in attachment
position in the previous step, an optical signal is optically
coupled reliably to the optical waveguide 30 by the adjustment
step. Therefore, the optical module 1 capable of transmitting the
optical signal with reduced loss is obtained.
[0049] In the adjustment step, the orientation of the mirror 12 is
manipulated by applying an external force F to a handle 11a of the
manipulation lever 11 located on the side opposite to the optical
waveguide 30 with respect to the position where the mirror 12 is
disposed. The handle 11a may be grasped by a manipulator or may be
provided with a hook. The external force applied to the handle 11a
may be a contact force directly applied by the manipulator.
However, the external force applied to the handle 11a may be a
distant force such as an electrostatic force.
[0050] Further, the method for manufacturing the optical module 1
according to the embodiment includes, after the adjustment by the
adjustment step, a brazing step of flowing the brazing material 15
between the manipulation lever 11 and the SOI substrate 10, and
brazing the manipulation lever 11 to the SOI substrate 10. The
brazing material 15 is melted by heating with an electric current
flowing through the electrode 14, and is caused to flow between the
manipulation lever 11 and the SOI substrate 10. With this
configuration, the manipulation lever 11 is fixed in the state
where the optical coupling is ensured, and thus the optical module
1 in which each laser light oscillated from the array device is
optically coupled reliably to the optical waveguide 30 is
obtained.
[0051] In the optical module 1 according to the embodiment, the
support spring 13 extends in the direction different from the
manipulation lever 11. That is, the manipulation lever 11 extends
in the z-axis direction, while the support spring 13 extends in the
x-axis direction. Moreover, two support springs 13 are provided in
the opposite directions so as to support the mirror 12. Since the
support spring 13 extends in the direction different from the
manipulation lever 11, the direction in which the support spring 13
easily stretches or compresses (the x-axis direction in the example
of FIG. 3) is orthogonal to the extending direction of the
manipulation lever 11, and thus the movable range of the mirror 12
is widened. Moreover, since the two support springs 13 are provided
in the opposite directions so as to support the mirror 12, the
twisting of the mirror 12 is inhibited when the manipulation lever
11 is manipulated, and thus the orientation of the mirror 12
becomes stable.
[0052] In the optical module 1 according to the embodiment, the
fulcrum of the support spring 13 is not provided between the mirror
12 and the optical waveguide 30 but is provided away from the
mirror 12 in the direction in which the support spring 13 does not
approach the optical waveguide 30. With this configuration, the
distance between the mirror 12 and the optical waveguide 30 can be
reduced, and thus the optical module 1 can be downsized. Although
the support spring 13 is referred to as "spring" in the embodiment,
this only expresses the function thereof. The support spring 13
does not need to have the so-called spring shape as long as the
support spring 13 can elastically operate the mirror 12, and may be
some kind of an elastic body.
[0053] FIG. 4 is a top view showing an optical axis adjustment
mechanism of an optical module la according to a first modified
example of the embodiment of the invention. In the optical module
1a of the modified example, the mirror 12 is supported by a first
cantilever spring 13a. Moreover, the electrode 14 and the brazing
material 15 are provided only on the side where the first
cantilever spring 13a is provided.
[0054] Even when the first cantilever spring 13a is included as in
the modified example, the orientation of the mirror 12 can be
changed by manipulating the manipulation lever 11, and the laser
light can be optically coupled to the optical waveguide 30.
Moreover, the manipulation lever 11 can be brazed by flowing the
brazing material 15 after the optical axis adjustment step.
[0055] By providing the first cantilever spring 13a, the electrode
14, and the brazing material 15 on one side in an unbalanced manner
as in the modified example, the optical axis adjustment mechanism
can be further downsized compared with the first embodiment, and
the entire optical module la can be downsized when formed into an
array form. Moreover, employing the first cantilever spring 13a
enables the mirror 12 to be greatly displaced with a relatively
small external force.
[0056] FIG. 5 is a top view showing an optical axis adjustment
mechanism of an optical module 1b according to a second modified
example of the embodiment of the invention. In the optical module
1b of the modified example, a plurality of support springs
(inclined springs 13b) are provided to extend in the directions
different from each other. Specifically, two inclined springs 13b
are provided for the mirror 12, and inclined from the x-axis
direction to the positive direction of the z-axis. Since the
plurality of inclined springs 13b provided to extend in the
directions different from each other are included, the direction in
which the inclined spring 13b easily stretches or compresses (the
extending direction of the inclined spring 13b) is not orthogonal
to the x-axis, and thus it becomes easy to move the mirror 12 in
the z-axis direction. Moreover, the width of the optical axis
adjustment mechanism in the x-axis direction can be made narrower
than that when two support springs are provided in the same
direction, and thus the optical module 1b can be downsized.
[0057] FIG. 6 is a top view showing an optical axis adjustment
mechanism of an optical module 1c according to a third modified
example of the embodiment of the invention. In the optical module
1c of the modified example, a manipulation lever (bent lever 11b )
is bent to connect to the mirror 12, and extends along a support
spring (second cantilever spring 13c). The bent lever 11b connects
to the mirror 12 in the x-axis direction, and is bent to extend in
the z-axis direction. The second cantilever spring 13c is provided
between the mirror 12 and the SOI substrate 10, and extends in the
z-axis direction. Even when the bent lever 11b and the second
cantilever spring 13c are included as described above, the optical
axis of laser light reflected by the mirror 12 can be adjusted, and
the optical module 1c can be downsized.
[0058] FIG. 7 is a side view showing an optical module 1d according
to a fourth modified example of the embodiment of the invention.
The optical module 1d according to the modified example further
includes an optical isolator 40 between the mirror 12 and the
optical waveguide 30. The optical isolator 40 transmits a light
wave traveling in the positive direction of the z-axis, but blocks
a light wave traveling in the negative direction of the z-axis.
Therefore, the return light to the array-type semiconductor laser
device 20 is suppressed.
[0059] Moreover, in the optical module 1d according to the modified
example, the lens formed integrally with the array-type
semiconductor laser device 20 is a collimating lens 24. The
collimating lens 24 converts divergent light reflected by the
mirror surface 22 to parallel light, and allows the parallel light
to be incident on the mirror 12. Therefore, the parallel light is
incident on the optical isolator 40.
[0060] A focusing lens 41 is provided between the optical isolator
40 and the optical waveguide 30. The focusing lens 41 focuses the
parallel light transmitted through the optical isolator 40 to be
optically coupled to the optical waveguide 30. In the modified
example, the joint portion between the support spring 13 and the
SOI substrate 10 is not located on the optical waveguide 30 side,
and an empty space is provided between the mirror 12 and the
optical waveguide 30. Therefore, the optical isolator 40 and the
like can be disposed in this space as shown in the modified
example, and a great increase in the size of the entire optical
module 1d can be prevented.
[0061] FIG. 8 is a side view of an optical module 1e according to
another embodiment of the invention. In the optical module 1e
according to the embodiment, the photonic device is an array-type
semiconductor light-receiving device 50. The array-type
semiconductor light-receiving device 50 is a device that receives a
light wave transmitted by the optical waveguide 30 and reflected by
the mirror 12 and reads the content of an optical signal. A lens 51
is formed integrally with the array-type semiconductor
light-receiving device 50, and focuses and receives the divergent
light reflected by the mirror 12.
[0062] In a method for manufacturing the optical module 1e
according to the embodiment, in the adjustment step, the
orientation of the mirror 12 is manipulated with the manipulation
lever 11 to adjust the traveling direction of the light wave
reflected by the mirror 12, and the light wave is adjusted so as to
be optically coupled to the array-type semiconductor
light-receiving device 50. As described above, even when the
array-type semiconductor light-receiving device 50 or the optical
waveguide 30 has an error in attachment position, the optical
signal is optically coupled reliably to the array-type
semiconductor light-receiving device 50, and thus the optical
module 1e capable of reading the optical signal with reduced loss
is obtained.
[0063] While there have been described what are at present
considered to be certain embodiments of the invention, it will be
understood that various modifications may be made thereto, and it
is intended that the appended claims cover all such modifications
as fall within the true spirit and scope of the invention.
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