JP2000081548A - Parts for optical signal transmission and reception - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid trouble that a light emitting element is made unstable by returning of the reflected return light from the ends of waveguide to the light emitting element by working the end face of the optical waveguide for coupling the light emitting element diagonally with the optical axis and working the end face of the optical waveguide for coupling a photodetector perpendicularly to the optical axis. SOLUTION: The end face of the optical waveguide 1 for coupling the light emitting element 2 is worked diagonally at θ=5 to 20 deg. with the optical axis. As a result, the return light to the light emitting element 2 is decreased. A working method includes diagonal cutting by a dicing saw and diagonal polishing of the end faces of the waveguides. When θ is below 5 deg., the return light to the light emitting element 2 increases. Otherwise, in the case of diagonal cutting by the dicing saw. When θ exceeds 20 deg., the distance between the light emitting element 2 and the optical waveguide 1 increases and the coupling loss increases. The end face of the optical waveguide 1 coupling the photodetector 4 is worked perpendicularly to the optical axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical communication and optical LA.
The present invention relates to an optical transmission / reception component for photoelectric signal conversion used for optical signal transmission between device devices in optical measurement control and the like.

[0002]

2. Description of the Related Art Conventionally, optical components such as mirrors and lenses, light emitting elements and light receiving elements have been combined as components for transmitting or receiving optical signals between electronic equipment devices (optical transmitting and receiving components). Various optical transmitting and receiving components having a structure in which optical fibers for inputting and outputting data are coupled have been developed. However, these conventional optical transmission / reception components require a large number of optical components to be spatially arranged and manufactured with their optical axes aligned, so that mass production is difficult, and a large number of optical components are individually arranged. Therefore, there was a problem in environmental characteristics such as vibration, impact, and temperature change. Furthermore, since a large number of optical components are spatially arranged, miniaturization has been difficult.

[0003] To solve these conventional problems, as a smaller and more reliable optical transmitting / receiving component, an optical signal input / output for optical signal input / output is provided at an end of an optical waveguide (polymer optical waveguide) using a polymer film. For this purpose, an optical fiber, a light emitting element and a light receiving element are connected and fixed to be integrated (Japanese Patent Application Laid-Open Nos. 6-34833, 6-75141, and 8-329779). Gazette, Japanese Patent Application No. 9-288374). Among them, in particular, Japanese Patent Application Nos. 8-329779 and 9-288374.
The publication relates to a light transmitting / receiving component in which a waveguide end and a light receiving / emitting element are optically coupled with a space therebetween,
By separating the waveguide and the element, environmental resistance such as temperature cycling is remarkably improved, and an extremely reliable optical transmitting and receiving component is obtained.

[0004]

However, in these optical transmitting and receiving parts in which the waveguide and the light receiving / emitting element are coupled with a space therebetween, light from the light emitting element is partially reflected at the end of the waveguide to emit light. It has been found that returning to the element itself makes the light emission unstable, resulting in an increase in noise level.

In order to avoid the influence of such reflected return light, it is effective to prevent the reflected return light from the waveguide end face facing the light emitting element from directly entering the element.
As this means, there is a method of covering the end face other than the waveguide portion with a black coating film or the like to block the reflection itself, or a method of processing the end face obliquely with respect to the optical axis. FIG. 1 shows a case where the entire waveguide end face is processed obliquely. In FIG.
Reference numeral 1 denotes an optical waveguide in which one end is processed at an angle θ.
Reference numeral 2 denotes a light emitting element (usually used in combination with a lens), and reference numeral 3 denotes light emitted from the light emitting element (2), and an optical waveguide.
This is the reflected return light reflected by the end face of (1). In this figure, the reflected return light (3) returns in a direction shifted by an angle of 2θ from the incident light. Therefore, by increasing the angle θ to a certain degree or more, the return light to the light emitting element (2) itself is greatly reduced. Becomes possible.

[0006] However, in the case of an optical transmission / reception component in which not only a light emitting element but also a light receiving element is coupled to one waveguide end face, and the optical axes of the waveguides at the end faces are parallel to each other, the entire end face is oblique. When light is processed, the light traveling from the end of the waveguide facing the light receiving element to the light receiving element changes its direction largely by refraction at the waveguide end face. It has been necessary to adjust the relative positions of the elements individually, and a problem has arisen that simple and rational production cannot be performed.

[0007]

Means for Solving the Problems The present inventors have proposed an optical transmission / reception device that couples at least one light emitting element and at least one light receiving element to a plurality of waveguide ends exposed at one end face of an optical waveguide with a space therebetween. It has been completed as a result of intensive studies on a method of processing the end face of the optical waveguide suitable for a component for use. That is, according to the present invention, an optical waveguide having waveguide ends at predetermined intervals on one end face, and at least one light emitting element and at least one light receiving element separated from the one end face by a space are optically connected to the waveguide. An optical transmission / reception component formed by coupling, wherein an end face of the optical waveguide at an end portion of the waveguide that couples the light emitting element is processed at an angle of 5 to 20 degrees with respect to an optical axis to couple the light receiving element. The end face of the optical waveguide at the end portion of the waveguide is an optical transmission / reception component that is processed perpendicular to the optical axis.

FIG. 2 specifically shows the present invention.
In FIG. 2, reference numeral 1 denotes an optical waveguide, reference numeral 2 denotes a light emitting element,
Reference numeral 4 denotes a light receiving element. That is, the present invention provides an optical waveguide (1) having waveguide ends at predetermined intervals on one end surface and at least one light-emitting element (2) and at least one light-receiving element (4) separated from the one end face by a space. Are optically coupled to the waveguide, respectively, wherein the optical waveguide end face of the waveguide end portion coupling the light emitting element is inclined at θ = 5 to 20 degrees with respect to the optical axis. The optical waveguide end face of the waveguide end portion that couples the light receiving element is an optical transmitting / receiving component that is processed perpendicular to the optical axis.

If the end face of the optical waveguide portion to be coupled to the light emitting element is not inclined as shown in FIG. 2, but is inclined as a whole as shown in FIG. 3, the following inconvenience occurs, which is not preferable. That is, if the end face of the optical waveguide portion is inclined, the light emitted from the end face of the optical waveguide is bent,
The pitch d between the central axis of the light receiving element and the central axis of the light emitting element differs depending on the position of the end face of the optical waveguide and the position of the light receiving element. In other words, it is necessary to strictly adjust the position of the light emitting element. On the other hand, in the case of the structure according to the present invention, the pitch d between the central axis of the light receiving element and the central axis of the light emitting element is constant irrespective of the distance between the optical waveguide and the light receiving element. is there.

In practicing the present invention, the angle θ of the end face of the end portion of the waveguide connecting the light emitting element to the optical axis is 5 °.
It is preferable to process to not less than 20 degrees. By employing such a structure, return light to the light emitting element itself can be significantly reduced, and the light emitting element can be stabilized. Also, there is no need to strictly adjust the relative position between the waveguide and the light receiving element. Examples of the processing method include oblique cutting with a dicing saw (cutting in a direction perpendicular to the waveguide surface), and oblique grinding of the end surface of the waveguide (polishing with a diagonally fixed jig). If θ is less than 5 degrees, reflected return light to the light emitting element increases, which is not preferable. Also, in the case of oblique cutting with a dicing saw, if θ exceeds 20 degrees,
It is not preferable because the distance between the light emitting element and the optical waveguide becomes longer and the coupling loss increases.

In practicing the present invention, the optical waveguide is not particularly limited, but in view of mass productivity, a polymer optical waveguide manufactured by a solvent casting method is particularly preferable. Also,
INDUSTRIAL APPLICABILITY The present invention is particularly effective for an optical transmission / reception component in which a light emitting element is a laser diode and a light collecting lens is provided in front of the light emitting element. The optical waveguide of the present invention is a 1: N (N is an integer of 2 or more) type having one waveguide end to be coupled to a transmission line and a plurality of branch waveguide ends on the opposite surface, and is coupled to a plurality of optical transmission lines. M: N (where M and N are equal to 2) having a plurality of waveguide ends to be
The above integer) type, further, at least one trunk waveguide coupled with the optical transmission line at one end face and its opposite end face;
One having at least two branches branched from the main waveguide and a pair of branch waveguide end faces is exemplified.

[0012]

EXAMPLES Hereinafter, the optical transmission / reception component of the present invention will be described in more detail with reference to examples. The following examples are for the purpose of specifically explaining, and do not limit the embodiments and the scope of the present invention.

Example 1: Fabrication of optical fiber transmitting / receiving component for optical fiber having a core diameter of 50 μm FIG. 4 shows an optical fiber transmitting / receiving component according to the present invention. Reference numeral 11 denotes a can type photodiode (PD: S5972 manufactured by Hamamatsu Photonics Co., Ltd.), and reference numeral 12 denotes a can type laser diode (L: 0.78 μm).
D: RLD78PIT manufactured by ROHM Co., Ltd., reference numeral 13 is a 2 mmφ rod lens (for 0.78 μm, 0.25 pitch) as a condenser lens, and reference numeral 14 is stainless steel for storing the LD (12) and the rod lens (13). Sheath (2.05mmφ inside diameter, 6mm outside diameter)
φ, length 8mm), symbol 15 is for optical fiber with core diameter 50μm
2 Branched optical waveguide, reference numeral 16 is an optical waveguide plate sandwiching the optical waveguide between upper and lower glass plates, reference numeral 17 is a stainless steel support can, reference numeral 18 is a receptacle, reference numeral 19 is a receptacle (18) and a support can (17). This is a fixing ring for fixing).

(Preparation of Can Body (17)) The outer shape of the can body (17) for supporting an optical component has a left-right length of 23 mm, a vertical width of 20 mm, and a height of 9 mm.
mm, the left side wall of which is 3.5 mm thick and has a through hole for fixing the optical receptacle, while the right side wall has a thickness of 6 mm.
A hole for fixing the light receiving element and the light emitting element is formed in mm, and has a storage portion for the two-branch optical waveguide plate (16) inside. Also, when the optical waveguide plate (16) and the light receiving element (11) are housed in the can (17), the accuracy is such that the optical axis of the optical waveguide (15) matches the optical axis of the light receiving element (11). The can body (17) is manufactured. Further, screw holes for fixing components are provided at four corners of the can body (17). After assembling, a stainless steel lid is adhesively fixed inside these screw holes to maintain the airtightness inside.

(2 branch optical waveguide (15), circuit plate (16)
Production) The dimensions of the optical waveguide were as follows: the film thickness was 40 μm, the length in the propagation direction was 12 mm, the interval between the branch waveguides was 6 mm, and the width at the waveguide end was 40 μm on both the single side and the branch side, as follows. Produced. That is, a polycarbonate resin synthesized from bisphenol Z (Mitsubishi Gas Chemical Co., Ltd.)
And trade name: Iupilon Z), using trifluoroethyl acrylate as a photopolymerizable monomer and benzoin ethyl ether as a sensitizer (JP-B-56-3522, JP-A-3-156407). JP-A No. 1993) to produce an optical waveguide film.

Next, using an adhesive having a refractive index of 1.56,
A glass plate having a thickness of 1.5 mm was bonded and fixed to both sides of the optical waveguide film, and then cut into a predetermined size to obtain a two-branch optical waveguide. Next, the 1-port portion on the 2-branch optical waveguide side is
It was cut with a dicing saw that was 12 degrees diagonally.

(Preparation of Optical Receptacle (18)) Total Length 18.5m
m, outer diameter of insertion part to support can body (17) 5.99mm, length 7m
m optical receptacle (18) was fabricated. Here, an optical fiber with a ferrule is inserted inside the optical receptacle (18), and the end of the ferrule is configured to be in contact with the ferrule end on the optical connector side, and the opposite end is also provided. Similarly, it is configured to be in contact with the optical waveguide. In addition, the optical receptacle (18) can be
(17) For fixing by adhesive, inner diameter 6.01mm, outer diameter 9mm, thickness
A 2.5 mm fixing ring (19) was prepared.

(Light receiving element (11) and light emitting element (12)) The light emitting element (12) is integrated with a condenser lens and has a stainless steel sheath (14) (inner diameter 2.05 mmφ, outer diameter 6 mmφ, length 8 mm) inside. I put it in

(Assembling of Optical Transmitting / Receiving Parts) First, the light receiving element (11) was bonded and fixed to the through hole of the can (17). Next, the fixing ring (19) is passed through the optical receptacle (18) in advance, and the side connected to the optical waveguide plate (16) is inserted into the through hole of the can (17) from the outside, and placed inside the can. And placed on an optical stage. After that, the light from the LED light source with a wavelength of 0.85 μm is transmitted to the optical receptacle (18) using a 50 / 125GI optical fiber.
And adjust the position of the optical receptacle (18) using the light receiving element (11) fixed to the can body (17) as a monitor, and at the position where the light intensity is maximized, the optical receptacle (18) and the optical waveguide plate (16) was adhered and fixed.

Next, the LE connected to the optical receptacle (18)
The optical fiber from the D light source was removed and replaced with an optical fiber led from an optical power meter. In this state the light emitting element
(12) emits light, and adjusts the relative position between the optical waveguide plate (16) integrated with the optical receptacle (18) and the light emitting element (12). (1
9) through a can body (17), an optical receptacle (18), and a stainless steel sheath portion (1) integrated with the light emitting element (12).
4) Adhesively fixed. The time required for adjusting the position of the optical waveguide plate (16) and the stainless sheath portion (14) was 3 minutes on average for the manufacture of five pieces.

Comparative Example 1 Production of Optical Transmitting / Receiving Parts for Optical Fiber with 50 μm Core Diameter Five optical transmitting / receiving components for optical fiber having a 50 μm core diameter were manufactured in exactly the same manner as in Example 1. However, as shown in FIG. 3, the optical waveguide plate (16) was used by cutting the whole obliquely at an angle of 12 degrees. Also, the can body (17) and the light receiving element (11) are not bonded and fixed in advance, but the position adjustment between the optical waveguide plate (16) integrated with the optical receptacle (18) and the stainless sheath part (14). Was performed, the position of the light receiving element was also adjusted at the same time. When the position adjustment of the light receiving element was not performed, the same performance as that of Example 1 was not obtained. As a result, the time required for adjusting the positions of the optical waveguide plate (16), the light receiving element (11), and the stainless steel sheath portion (14) integrated with the optical receptacle (18) is an average of 11 times for manufacturing five pieces. Minutes.

[0022]

As described above, in an optical transmitting / receiving component in which a waveguide and a light receiving / emitting element are coupled with a space therebetween, reflected light returning from the end of the waveguide is transmitted to the light emitting element itself while maintaining the simplicity of the assembling work. The problem that the light emitting element becomes unstable by returning can be avoided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a positional relationship between reflected light when light is incident on an obliquely cut end surface.

FIG. 2 is a schematic view showing an example of an optical transmitting / receiving component for specifically illustrating the present invention.

FIG. 3 is a schematic view showing an example of an optical transmission / reception component in which the entire end face of the optical waveguide is obliquely processed for comparison with the effect of the present invention.

FIG. 4 is a plan view of an optical transceiver component according to the first embodiment.

[Explanation of symbols]

1: optical waveguide plate, 2: light emitting element, 3: reflected return light, 4: light receiving element, 11: light receiving element, 12: light emitting element,
13: rod lens, 14: stainless steel sheath, 1
5: Optical waveguide, 16: Optical waveguide plate, 17: Support can, 18: Receptacle, 19: Fixing ring

Claims (6)

[Claims] 1. An optical waveguide having waveguide ends at predetermined ends on one end, and at least one light-emitting element and at least one light-receiving element optically coupled to the end of the one end with a space therebetween. An optical transmission / reception component comprising: an end face of the optical waveguide at an end portion of the waveguide for coupling the light emitting element, which is processed at an angle of 5 to 20 degrees with respect to an optical axis to couple the light receiving element; An optical transmission / reception component in which an end face of the optical waveguide at an end portion of the waveguide is processed perpendicular to an optical axis. 2. The optical transmitting / receiving component according to claim 1, wherein the optical waveguide is a polymer optical waveguide manufactured by a solvent casting method. 3. The optical transmitting / receiving component according to claim 1, wherein the light emitting element is a laser diode, and a light condensing lens is provided in front of the laser diode. 4. The optical waveguide according to claim 1, wherein the optical waveguide is a 1: N (N is an integer of 2 or more) type having one waveguide end to be coupled to the transmission line and a plurality of branch waveguide ends on the opposite surface. Parts for optical transmission and reception. 5. An M: N (M and N are integers of 2 or more) type optical waveguide having a plurality of waveguide ends coupled to a plurality of optical transmission lines and a plurality of waveguide ends on opposite sides thereof. The optical transmitting / receiving component according to claim 1. 6. An optical waveguide comprising: at least one trunk waveguide coupled to an optical transmission line at one end face and its opposite end face; and at least two pairs of branch waveguide end faces branched from the trunk waveguide. The optical transmission / reception component according to claim 1, comprising: