Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
2000-10-10
2003-07-29
Palmer, Phan T. H. (Department: 2874)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S024000, C385S092000, C359S199200
Reexamination Certificate
active
06599032
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an optical parallel transmission transmitter/receiver used for optical communication, and an optical module substrate having optical elements (light-receiving element/light-emitting elements) and optical fibers.
BACKGROUND ART
Along with an increase in required transmission capacity, the optical parallel data transmission technology for optical communication systems is becoming promising. An optical communication system using the optical parallel data transmission technology is divided into three sections: a transmission section, optical fiber transmission line, and reception section. In the transmission section, a plurality of electronic signals forming a bit sequence are input, subjected to signal processing, waveform shaping, and amplification, and output as optical signals through a current driving circuit and light-emitting element. In the reception section, the optical signals are converted into electrical signals by light-receiving elements, and the signals are subjected to amplification and signal processing to restore the original electrical signal bit sequence (Latest Materials of Optical Communication Technology III, “Optical parallel Data Transmission Scheme and Hardware Configuration”, pp. 191-192).
To realize an optical communication system using the optical parallel data transmission scheme, it is necessary to {circle around (1)} accurately and easily align the optical axes of an optical element array and optical fiber array and fix them, and {circle around (2)} hermetically seal the optical element array which readily degrades due to a change in humidity or temperature. A technique is known for this purpose in which a bundle fiber is inserted between a plurality of optical elements and a plurality of optical fibers to optically couple the optical elements to the optical fibers (Japanese Patent Laid-Open No. 5-188250).
Additionally, as described in transactions “the 1995 IEICE Conference C-185”, a structure is known in which a V-groove is formed in the upper surface of a silicon substrate, a light-emitting element is positioned and fixed at a predetermined position on the distal end side of the V-groove, and an optical fiber is arranged in the V-groove, thereby matching the optical axes of the optical fiber and light-emitting element.
From the viewpoint of facilitation and automation of the manufacturing process, a structure has been proposed in which optical coupling to light-emitting elements or light-receiving elements is achieved using a ferrule in which optical fiber strands are inserted and fixed (Japanese Patent Application No. 9-83004).
As an element technique for optical parallel transmission, for example, Japanese Patent Laid-Open No. 7-209556 discloses an optical transmission/reception module which integrates an LD (Laser Diode) array, PD (PhotoDiode) array, optical fiber array for optically coupling the LD array and PD array, LD IC, and PD IC. In this optical transmission/reception module, to facilitate alignment between the LD array, the PD array, and the optical fiber array, an optical module substrate made of silicon and having a plurality of V-grooves is used, and the optical fiber is formed by inserting a plurality of optical fibers into the V-grooves in the optical module substrate. Silicon is used for the optical module substrate because working of V-grooves can be easily and accurately realized.
DISCLOSURE OF THE INVENTION
However, when a plurality of optical fibers and a plurality of optical elements (light-receiving elements or light-emitting elements) are to be optically coupled using the conventional system, operation becomes hard. For, e.g., a 12-fiber array, operation is greatly complicated unless shift due to rotation is taken into consideration, unlike a case wherein a single optical fiber is connected to an optical element.
In addition, when not only an optical fiber array but also a light-emitting element array (e.g., a laser array) or light-receiving element array is mounted on an optical module substrate, the alignment operation is to be further facilitated, and the size of light-emitting module or light-receiving module is to be reduced, the optical module substrate according to the prior art has the following problems.
A laser beam emitted from each of a plurality of exit regions of a laser array diverges to some extent. For this reason, when the laser array is mounted on the mounting surface of an optical module substrate, the laser beam emitted from each exit region is partially reflected by the mounting surface of the optical module substrate. As a consequence, the coupling efficiency of the optical fibers of the optical fiber array lowers, and light reflected by the mounting surface generates noise.
Leakage light from a reflection region opposing each of the plurality of exit regions is also reflected by the mounting surface. As a consequence, the light reflected by the mounting surface generates noise.
When a light-emitting element array or light-receiving element array is to be mounted on an optical module substrate, normally, printed interconnections for electrically connecting the light-emitting element array and driving circuit and the like, or the light-receiving element array and amplification circuit and the like must be formed on the optical module substrate. Especially, when the optical module substrate is formed from a conductive material such as silicon, interconnections cannot be directly formed on the surface by metallizing. hence, an insulating film is formed on the surface, and interconnections are formed on this insulating film. With this arrangement, however, operation errors occur in the light-emitting module due to the parasitic capacitance generated between the interconnections and the optical module substrate through the insulating film, or noise is generated in the light-receiving module.
It is an object of the present invention to provide a structure capable of easily realizing operation of optically coupling a plurality of optical fibers and a plurality of optical elements. It is another object of the present invention to provide an optical module substrate which prevents any operation error of a light-emitting module or reduce noise in a light-receiving module.
In order to achieve the above object, according to the present invention, there is provided an optical parallel transmission receiver in which a plurality of light-receiving elements and a plurality of optical fibers are optically coupled via guide pins, characterized by comprising a pair of guide pins, fiber holding means (e.g., a ferrule) for holding the pair of guide pins in parallel and holding the plurality of optical fibers (e.g., a tape-like optical fibers) between the pair of guide pins at a predetermined interval, and light-receiving element holding means for holding the plurality of light-receiving elements (e.g., a light-receiving element array) between the pair of guide pins and holding one end of each of the pair of guide pins so as to make a plane including light-receiving surfaces of the light-receiving elements perpendicular to longitudinal axes of the guide pins, wherein the fiber holding means and the light-receiving element holding means are integrally held by resin molding.
There is also provided an optical parallel transmission transmitter in which a plurality of light-emitting elements and a plurality of optical fibers are optically coupled via guide pins, characterized by comprising a pair of guide pins, fiber holding means for holding the pair of guide pins in parallel and holding the plurality of optical fibers between the pair of guide pins at a predetermined interval, and light-emitting element holding means for holding the plurality of light-emitting elements between the pair of guide pins and holding one end of each of the pair of guide pins so as to align optical axes of the light-emitting elements with core axes of the optical fibers, wherein the fiber holding means and the light-emitting element holding means are integrally held by resin molding.
According to th
Kurashima Hiromi
Mikamura Yasuki
Sakamoto Takashi
Tanaka Nobuyuki
Palmer Phan T. H.
Sumitomo Electric Industries Ltd.
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