Optical interconnection module

Details Optical interconnection module Optical interconnection module

2001-02-27

2002-10-22

Patel, Tulsidas (Department: 2839)

Optical waveguides

With disengagable mechanical connector

Optical fiber to a nonfiber optical device connector

Reexamination Certificate

active

06467972

ABSTRACT:

This application is based on patent applications 2000-054970, 2000-333609, and 2001-023415 filed in Japan, the contents of which are hereby incorporated by references.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical interconnection module used for optical data transmission and reception such as optical fiber communication.
2. Description of the Related Art
In a conventional optical interconnection module used for optical data communication, an optical semiconductor device such as a semiconductor laser for emitting light and an optical fiber optically interconnected to the laser are held on the same mounting substrate. Conductive patterns or electrodes are formed on the surface of the mounting substrate for supplying electric power to the optical semiconductor device. Furthermore, a V-shaped groove, on which the optical fiber is held, is formed on the mounting substrate. For realizing a desired interconnection efficiency, it is necessary to form the electrode and the V-shaped groove precisely on the mounting substrate so as to face the optical semiconductor device and the optical fiber precisely.
On the other hand, a condenser lens is used for interconnecting the optical semiconductor device and the optical fiber so as to obtain a desired interconnection efficiency. Since the optical semiconductor device and the optical fiber are fixed on the precisely finished mounting substrate, the optical semiconductor device and the optical fiber can be positioned much closer, and the condenser lens can achieve the desired interconnection efficiency.
A configuration of a first conventional optical interconnection module
70
, for example, shown in Publication Gazette of Japanese Patent Application Hei 7-63957 is shown in FIG.
19
.
As can be seen from
FIG. 19
, an optical semiconductor device such as semiconductor laser
72
is fixed on a mounting substrate
80
, and an optical fiber
82
is fixed on a V-shaped groove
86
to be optically interconnected with the semiconductor laser
72
. The mounting substrate
80
is contained in a cavity
74
of a package
71
. A narrow groove
81
and a wide groove
75
are formed on a top surface of the package
71
. The optical fiber
82
is directly disposed in the narrow groove
81
. A portion of the optical fiber
82
disposed in the wide groove
75
is covered by a protection film
83
and a ferrule
78
made of a glass tube. A metal plate
77
is fixed on the top surface of the package
71
for enclosing the cavity
74
. A cover
85
is further fixed on the metal plate
77
for closing an upper opening of the cavity
74
.
For sealing the cavity
74
, glass powder having a low melting point is filled in the narrow groove
81
, and the glass powder is locally heated to be melted by irradiation of laser light beam such as CO
2
laser. Thus, melted glass seals the gap between the optical fiber
82
and the narrow groove
81
.
A second conventional optical interconnection module with respect to the sealed packaging is proposed in Publication Gazette of Japanese Patent Application Hei 10-227953 (not shown in the figure). A gel resin having a refractive index larger than that of air but smaller than that of the optical fiber and optically transparency is filled in the cavity. A portion in which the gel resin is filled is further sealed by another resin having moisture resistance.
On the other hand, it is necessary to maintain a temperature of the optical semiconductor device at low and constant level for stabling the operation of the optical interconnection module by restricting the temperature rise due to the heat generated in the optical semiconductor device and an electronic circuit used for controlling the optical semiconductor device.
A configuration of a third conventional optical interconnection module
50
, for example, shown in Publication Gazette of Japanese Patent Application Hei 10-282373 is shown in FIG.
20
.
As can be seen from
FIG. 20
, an optical semiconductor device such as a semiconductor laser
52
is fixed on a first mounting substrate
53
, and a driving circuit
54
is fixed on a second mounting substrate
55
. The first and second mounting substrates
53
and
55
are respectively contained in the same cavity of a package
51
. An optical fiber
56
is optically interconnected with the semiconductor laser
52
by a condenser lens
57
. The semiconductor laser
52
is electrically connected to electrodes
58
and
59
formed on the first mounting substrate
53
and the driving circuit
54
on the second mounting substrate
55
by bonding wires
60
.
When an electric current flows in the driving circuit
54
for driving and controlling the semiconductor laser
52
, the driving circuit
54
is heated by the current flow, and the temperature of the driving circuit
54
increases. Similarly, when the semiconductor laser
52
is driven for emitting a light beam, the semiconductor laser
52
is heated by the energy conversion from electric energy to light energy, and the temperature of the semiconductor laser
52
increases. If the semiconductor laser
52
and the driving circuit
54
are fixed on the same mounting substrate, the temperature of the semiconductor laser
52
becomes much higher due to not only the self-heating but also the heat from the driving circuit
54
. When the temperature of the semiconductor laser
52
is risen, a frequency of the oscillated laser light will be varied and the output power will be reduced, so that they will be the cause of troubles of the optical interconnection module. For solving there problems, the mounting substrates are divided into the first mounting substrate
53
on which the semiconductor laser
52
is fixed and the second mounting substrate
55
on which the driving circuit
54
is fixed.
In the above-mentioned first conventional optical interconnection module
70
shown in
FIG. 19
, the optical fiber
82
and the glass tube
78
are held on the package
71
. When the package
71
is formed by lamination of ceramic thin plates, there is a possibility that the center axis of the narrow groove
81
and/or the center axis of the wide groove
75
is/are largely discrepant from the center of the package
71
.
Furthermore, the mounting substrate
80
, on which the semiconductor laser
72
and the optical fiber
82
are held, is fixed on the bottom of the cavity
74
of the package
71
. It, however, is difficult to coincide a center axis of the V-shaped groove
86
on the mounting substrate
80
with the center axis of the narrow groove
81
by basing on an outer shape of the mounting substrate
80
. The mounting substrate
80
is generally manufactured by the following method. A plurality of V-shaped grooves
86
are formed at predetermined positions on the same wafer having a size of several inches. Subsequently, each mounting substrate
80
with the V-shaped groove
86
is cut from the wafer by dicing. Since the dicing has a tolerance inevitably, it is difficult to finish the outer shape of the mounting substrate
80
precisely by dicing.
When the optical fiber
82
is fixed on the mounting substrate
80
and the package
71
with a discrepancy between the center axis of the V-shaped groove
86
and the center axis of the narrow groove
81
, the optical fiber
82
and the ferrule
78
cannot be fixed linearly. As a result, undesired bent called “micro-bend” occurs in the optical fiber
82
. When a circumferential condition of the optical interconnection module is varied, there is a possibility that the optical fiber will rupture at a portion where the micro-bend occurs.
It is not necessarily impossible that the optical fiber
82
and the ferrule
78
are precisely positioned linear in the narrow groove
81
and the wide groove
75
so as to coincide the center axes of the optical fiber
82
and the ferrule
78
with the center axes of the grooves
75
and
81
for preventing the occurrence of the micro-bend. It, however, is necessary to process a surface treatment to the optical fiber
82
to be observed easily, and to prepare a complex a

Affiliated with

Also associated with

Rating

Optical interconnection module does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Optical interconnection module, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical interconnection module will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2993238