Optical waveguides – With optical coupler – Input/output coupler
Reexamination Certificate
2001-12-28
2004-03-02
Healy, Brian (Department: 2874)
Optical waveguides
With optical coupler
Input/output coupler
C385S024000, C385S031000, C385S033000, C385S060000, C385S080000, C385S084000
Reexamination Certificate
active
06701041
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to optical filter modules and optical apparatuses using them, and particularly to an optical filter module including an optical filter, an optical system to guide the light to be supplied to the optical filter and the optical system to guide the light supplied from the optical filter, and various kinds of optical apparatuses such as an optical multi/demultiplexer using it or an optical equalizer.
2. Description of the Related Art
In a field of optics, an optical filter module is used, which is comprised of an optical filter to selectively transmit, attenuate, or reflect the light with a specific wavelength, and an optical system to supply the light to the optical filter or guide the light from the optical filter. For example, there known the apparatuses such as an optical multi/demultiplexer which multiplexes a plurality of lights with different wavelengths and demultiplexes the light to a plurality of lights with different wavelengths or a light equalizer which corrects intensity of the light that is not constant to the wavelength to the one that is constant.
FIG. 32
shows an optical multi/demultiplexer
90
as an example of an optical filter module. This optical multi/demultiplexer
90
is provided with a first collimator
100
having 2 optical fibers
101
and
102
, and a second collimator
110
having one optical fiber
111
, and a wavelength band-pass filter
95
arranged between these collimators
100
and
110
.
The first collimator
100
and the second collimator
110
have ceramic fiber holders
104
and
114
to hold the optical fiber. In the fiber holder
104
of the first collimator
100
, two through-holes having a circular sectional shape, are formed along its longitudinal direction, and in the fiber holder
114
of the second collimator
110
, one through-hole whose sectional shape is circular is formed along its longitudinal direction. The optical fibers are inserted into these through-holes, and held by being fixed by an adhesive agent.
Further, on the first collimator
100
and the second collimator
110
, rod lenses
103
and
112
to collimate and converge the light are provided. These rod lenses
103
and
112
are held by inner holders
105
and
115
together with the optical fiber holders
104
and
114
, and these inner holders
105
and
115
are fixed in an outside holder
120
by using the adhesive agent or soldering, or a method such as a YAG welding.
A wavelength band-pass filter
95
is closely contacted under the close contact condition to the rod lens
103
, and fixed by the adhesive agent
107
coated around the closely contacted surface.
When the light is demultiplexed by such an optical multi/demultiplexer
90
, the light incident into one of optical fibers of the first collimator
100
is collimated by the rod lens
103
, and reaches the wavelength band-pass filter
95
. The light of the wavelength reflected by this wavelength band-pass filter
95
passes through the rod lens
103
, and emitted from the other optical fiber of the first collimator
100
. On the other hand, the light passes through the wavelength band-pass filter
95
is converged by the rod lens
112
of the second collimator
110
and emitted from the optical fiber
111
.
Further, when the light is multiplexed by such an optical multi/demultiplexer
90
, the light incident from the optical fiber
111
of the second collimator
110
, is multiplexed with the light introduced one of the optical fibers of the first collimator
100
, and outputted from the other optical fiber of the first collimator.
However, in such the optical multi/demultiplexer
90
as described above, there is sometimes a case where the adhesive agent
107
before hardening, which is coated on the outer peripheral surface of the rod lens
103
and wavelength band-pass filter
95
penetrates between the closely contacted surfaces of the rod lens
103
and the wavelength band-pass filter
95
by a capillary phenomenon. Further, the closely contacted surface of the wavelength band-pass filter
95
is inclined to the closely contacted surface of the rod lens
103
, thereby, a gap is generated between the rod lens
103
and the wavelength band-pass filter
95
, and there is a case where the adhesive agent
107
before hardening penetrates from the gap.
When this adhesive agent
107
reaches a central portion of the closely contacted surface including the optical path, the adhesive agent interrupts the optical path and increases the loss of the light. Further, there is also a case where, by the temperature change under the using environment, the adhesive agent
107
penetrated into the closely contacted surfaces is expanded and contracted, and the position dislocation of the wavelength band-pass filter
95
is generated, or the stress is generated by the contact of the optical parts, and the loss of the light is increased.
SUMMARY OF THE INVENTION
In order to prevent this, it is considered that, as the adhesive agent
107
, the adhesive agent whose viscosity is high is used, and the penetration into between closely contacted surfaces is prevented, however, even when such the adhesive agent is used, it is difficult to perfectly prevent the penetration. Further, in the adhesive agent whose viscosity is high, the control of the coating amount is difficult, and there is also a problem that a dispenser to coat the adhesive agent is high in cost. Further, there is also a problem that, naturally, in the closely contacting of the optical parts, because it is necessary to use the adhesive agent whose thermal expansion property is low, the width of the selection of the adhesive agent having a predetermined viscosity is very narrow.
The present invention is attained for solving the above problems, and an object of the present invention is to provide a optical filter module by which the loss of the light by the adhesive agent penetrated between the closely contacted surfaces of the rod lens and the optical filter can be reduced, and each kind of optical devices such as an optical multi/demultiplexer using it.
In order to attain the above object, the optical filter module in the present invention is provided with an optical filter to selectively transmit, attenuate or reflect the light with a specific wavelength, and the first optical system including the optical fiber to guide the light to be supplied to the optical filter, and the second optical system which is oppositely provided to the first optical system through the optical filter, and which includes the optical fiber to guide the light to be supplied from the optical filter, wherein each of the optical systems has the a lens to optically connect the optical fiber and the optical filter, and the surface including the optical path of the optical filter is closely contacted by the adhesive agent coated on a portion which is not the optical path, under the closely contacted with the end surface including the optical path of any one lens of the first or second optical systems, and a groove portion to stay the adhesive agent penetrated between the closely contacted surfaces on at least one closely contacted surface of the optical filter and the lens, and to interrupt the adhesive agent from invading into the optical path is formed.
Further, the optical filter module of the present invention is provided with an optical filter to selectively transmit, attenuate or reflect the light with a specific wavelength, and the first optical system including the optical fiber to guide the light to be supplied to the optical filter, and the second optical system which is oppositely provided to the first optical system through the optical filter, and which includes the optical fiber to guide the light to be supplied from the optical filter, wherein each of the optical systems has the a lens to optically connect the optical fiber and the optical filter, and on the end surface of one lens of the optical system, a convex surface including the optical path and a flat portion protruded to the outside of the o
Asai Hidekuni
Kagami Kaoru
Kurosawa Toshihisa
Yokoo Yoshiatsu
Yokoyama Seiichi
Healy Brian
Hoya Corporation
Petkovsek Daniel
Sughrue & Mion, PLLC
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