Optical waveguides – With optical coupler – Particular coupling structure
Reexamination Certificate
2002-08-12
2004-11-23
Palmer, Phan T. H. (Department: 2874)
Optical waveguides
With optical coupler
Particular coupling structure
C385S147000
Reexamination Certificate
active
06823116
ABSTRACT:
The present application is based on Japanese Patent Applications No. 2000-365223, 2000-402883, 2001-54705 and 2001-165068, which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing an optical transmission device composed of a core portion and a clad portion from the photosetting resins. Further, the present invention is relates an optical transmission and reception module to be connected to an optical fiber and its manufacturing method.
2. Description of the Related Art
A conventional technique for forming an optical transmission device at the tip of an optical fiber using the photosetting resins is well known as described in Unexamined Japanese Patent Publication No. Hei. 4-165311, for example. This technique involves forming the optical transmission device by dipping one end of the optical fiber in a photosetting resin solution composed of fluorine monomer and applying a short wavelength laser in the ultraviolet radiation region from the optical fiber to the resin solution.
However, the conventional technique as above had the problem that a core could be only formed, unhardened monomer might stick to the optical transmission device formed, which necessitated a washing process, and the core was formed like a gourd as shown in
FIGS. 1
to
3
of the above publication, and could not be formed cylindrically.
Further, a metal cable for transmitting or receiving an electrical signal has been employed for the communication between the devices. The typical metal cable is conformable to the IEEE1394 standard standardized by the IEEE (Institute of Electrical and Electronic Engineers). In this IEEE1394 standard, the Data signal and the Strobe signal relevant to it are transmitted simultaneously.
More particularly, a metal cable
150
conforming to the IEEE1394 standard typically has a 6-pin connector
154
(or alternatively a 4-pin connector) connected at both ends of a cable
152
, as shown in FIG.
22
. Each pin of the connector
154
(in the order from the first pin to the sixth pin) is supplied with a power source (voltage) from an outside apparatus connected to the connector
154
and the GND to enable four signals of TPA, TPA*, TPB and TPB* to be input or output. A sign “*” denotes an inverse signal. On the receiving apparatus, TPA and TPA* are received and either one of them is used as the Data signal, and TPB and TPB* are received and either one of them is used as the Strobe signal.
The cable
152
has internally two pairs of pair signal conductors
156
A,
156
B that are called an STP (Shielded Twist Pair Cable), a power conductor
158
for supplying an electric power and a ground conductor
160
, whereby one cable
152
has a total of six lines. To reduce the influence of noise caused by the electric or magnetic field, the cable
152
has each of the pair signal conductors
156
A,
156
B twisted and covered with a shield
162
A,
162
B, and further is covered entirely with a shield
164
.
However, in the IEEE1394 standard, the STP is less sufficient to prevent signal deterioration due to the noise, the length of cable being limited to 4.5 m, which means that the STP can not be employed for the long distance connection between the devices.
Therefore, the IEEE1394.b standard for optical transmission is about to be instituted to enable the connection between the remote sites by optically transmitting or receiving the signal. This IEEE1394.b standard is intended for the bi-directional communications, employing two wires.
Also, a technique for the multi-directional communications has been proposed. In this technique, an optical module for enabling the bi-directional communications through the single wire line has been examined.
However, to employ the IEEE1394.b standard to constitute the devices, each device must be equipped with the IEEE1394.b standard, so that the total system is more expensive. Further, if there is the need of making connection to the conventional device conforming to the IEEE1394 standard, each device must be equipped with two standards, so that the cost of the total system is increased.
Since the optical module examined above makes the bi-directional communication through the single wire line, it is necessary to have different light wavelengths for transmission and reception to improve the signal quality. This is required to decrease the cross talk of light. Therefore, the optical module has the higher cost.
SUMMARY OF THE INVENTION
The present inventors have made careful researches and found that an effective optical transmission device can be formed by employing two kinds of photosetting resins, and attained the present invention.
Namely, it is an object of the invention to provide a method for manufacturing an optical transmission device with favorable conditions for forming the effective optical transmission device employing two kinds of photosetting resins.
It is another object of the invention to provide a method for manufacturing a self-forming optical transmission device which can be formed in a desired terminal area even if the optical transmission device is deviated from a desired direction.
It is still another object of the invention to provide an optical transmission and reception module and a communication device which can effect stable communications of two relevant signals in simple and inexpensive manner, irrespective of a device-to-device distance.
Further, it is still another object of the invention to provide a method for forming an optical transmission device in which it is unnecessary to make the alignment of optical axis after forming the optical transmission device, and an optical transmission and reception module produced by this method.
In order to accomplish the above object, according to one aspect of the present invention, there is provided a method for manufacturing an optical transmission device including a mixing step for mixing a first photosetting resin comprising a first photopolymerization initiator and a first monomer or oligomer polymerized in a first polymerization type by the first photopolymerization initiator, and a second photosetting resin comprising a second photopolymerization initiator and a second monomer or oligomer polymerized in a second polymerization type that is different from the first polymerization type by the second photopolymerization initiator, a core forming step for forming a core portion of the optical transmission device by hardening the first photosetting resin by making the first irradiation that activates the first photopolymerization initiator but does not activate the second photopolymerization initiator, and a clad forming step for forming a clad portion of the optical transmission device by hardening both the first photosetting resin and the second photosetting resin by making the second irradiation that activates both the first and second photopolymerization initiators, characterized in that the first irradiation has a wavelength shorter than the longest wavelength required to activate the first photopolymerization and longer than the longest wavelength required to activate the second photopolymerization.
The core portion is formed by hardening the first photosetting resin, and the clad portion is formed by hardening each of the first and second photosetting resins, whereby the first photosetting resin after being hardened is required to have a high refractive index than the second photosetting resin after being hardened. Also, in the clad formation step, each of the first and second photosetting resins is hardened, but not copolymerized. After forming the core, if two photosetting resins are both hardened by second irradiation, and the refractive index of hardened mixed resins is lower than before, the clad portion can function. Herein, it is required to activate the first or second photopolymerization initiator at the longest wavelength necessary to cause hardening to form the core portion substantially.
According to another aspect of the invention, there is provided a method for manufac
Inui Yukitoshi
Ito Hiroshi
Kagami Manabu
Kawasaki Akari
Kondo Kuniyoshi
McGinn & Gibb PLLC
Palmer Phan T. H.
Toyoda Gosei Co,., Ltd.
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