GB2317244A

GB2317244A - Making optical waveguides

Info

Publication number: GB2317244A
Application number: GB9718024A
Authority: GB
Inventors: Tae-Hyung Rhee; Byong-Gwon You
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1996-09-16
Filing date: 1997-08-27
Publication date: 1998-03-18
Anticipated expiration: 2017-08-27
Also published as: KR100263195B1; GB2317244B; JPH10104452A; KR19980021368A; DE19740727A1; GB9718024D0; FR2753541A1; RU2129722C1

Abstract

Optical waveguide component patterns 12 are formed on a wafer substrate by means of photolithography. The optical waveguide component patterns 12 with waveguides 14 are formed obliquely at a specified angle (#) to horizontal 16 scribe lines on the wafer. The wafer is cut along the horizontal 16 and vertical 18 scribe lines to form a plurality of optical waveguide components 12. The oblique angle decreases return losses when the optical waveguide components are joined to optical fibres. The angle # is preferably set above the numerical aperture in the waveguides.

Description

1 2317244 METHOD OF FABRICATING OPTICAL WAVEGUIDE COMPONENTS

Backaround of the Invention

The present invention relates to a method for forming optical waveguide component patterns on the wafer surface by means of photolithography.

Generally, the major problems to be handled when joining optical waveguide components to optical fibres are, for example, Fresnel reflection loss, misalignment loss and performance degradation of the optical waveguide component due to light reflection at the joint between the optical waveguide component and the optical fibre.

According to current technology, the joint loss problems due to misalignment and Fresnel reflection are almost settled, but return loss of about 30 dB is produced when bringing the optical waveguide and the optical fibre into contact with each other. As the result of this return loss, crosstalk is induced due to the change of optical path, which directly affects the stability of the entire system. Accordingly, to eliminate such adverse phenomenon, the ends of the optical waveguides and the optical fibre array are ground obliquely at an angle of 7-8 degrees before the optical components are joined together.

The conventional method for fabricating an optical waveguide component to be joined to the optical fibre is illustrated in Fig. 1. Referring to Figs. 1 and 2, af ter a silicon wafer 10 and a photo mask are vertically aligned, a plurality of optical waveguide component patterns 30 are formed on the wafer 10 by means of photolithography. Then the optical waveguide component patterns 30 are cut along vertical scribe lines 18 and horizontal scribe lines 16.

The vertical and horizontal scribe lines 16, 18 cross each other perpendicularly, and when cutting the wafer 10 along both sets of scribe lines, the optical waveguide component 2 patterns 30 are separated, each comprising a plurality of optical waveguides 32 which constitute an optical waveguide component.

Thereafter, the ends of the optical waveguide components 32 are ground obliquely at an angle of approximately 8 degrees so that the contact faces 34 are all inclined by 8 degrees. As described above, the conventional method has the drawback that the optical waveguide component patterns 30 are first formed vertically on the wafer, then cut along the vertical and horizontal scribe lines into a plurality of separate optical waveguide components and finally the end faces of all the optical waveguide components are ground obliquely at an angle of approximately 8 degrees.

Summary of the Invention

An objective of the present invention is to provide a method of fabricating optical waveguide components of reduced fabrication time and reduced production cost.

Accordingly, the present invention provides a method of fabricating optical waveguide components comprising forming optical waveguide component patterns on a wafer substrate by means of photolithography, the optical waveguide component patterns being formed obliquely at a specified angle (0) to vertical and horizontal scribe lines on the wafer.

Preferably, the method further comprising cutting the wafer 30 along the horizontal and vertical scribe lines to form a plurality of optical waveguide components. The said angle (0) may be 1-20 degrees.

The optical waveguide component patterns may be used as a silica optical waveguide element, a polymer optical waveguide element, a laser diode or a photodetector element. The wafer substrate may be a silicon wafer, a gallium arsenide wafer, a lithium niobate wafer or a quartz 3 wafer.

The method may further comprise connecting the optical waveguide components to with one or more optical fibres at the said angle (0). Preferably, the said angle (0) is above the value of the numerical aperture (NA) inherent in the optical waveguide components and the optical fibres.

Brief Description of the Drawinas

The present invention will now be described by way of example with reference to the accompanying drawings in which:

Fig. 1 is a top plan view of optical waveguide component patterns formed at right angles on a wafer; Fig. 2 is an enlarged view of 'W' as shown in Fig. 1; Fig. 3 is a top plan view of optical waveguide component patterns formed obliquely on a wafer; Fig. 4 is a schematic diagram illustrating optical waveguide component patterns formed obliquely at an angle (x) to the scribe lines on a wafer; and Fig. 5 is an enlarged view of "B" as shown in Fig. 4.

Detailed Description of the Preferred Embodiment

Referring to Fig. 3 and 4, after a silicon wafer 10 and a photo mask are aligned at a specified angle with respect to each other, a plurality of optical waveguide component patterns 12 are formed on the wafer 10 by means of a photolithographic process. As for wafer materials, gallium arsenide (GaAs), lithium niobate (LiNb03) and quartz (Si02) may be used. As optical waveguide component patterns, silica waveguide elements, polymer waveguide elements, laser diodes or photodetector elements may be used.

Referring to Fig. 4, the optical waveguide component patterns 12 are formed obliquely at a specified angle (0) to the vertical and horizontal scribe lines 16, 18 on the wafer. To decrease return loss when the optical fibres are joined to the optical waveguide components, the angle (0) 4 is set to above the value of the numerical aperture (NA) inherent in the optical waveguides 14 and the optical fibres, more particularly to an angle of approximately 1-20 degrees.

Thereafter, all the optical waveguide component patterns are cut along the vertical and horizontal scribe lines 16, 18 by maintaining the specified angle, whereby all the optical waveguide component patterns 12 are separated, each comprising a plurality of optical waveguides 14 which constitute an optical waveguide component.

As described above, this method for fabricating the optical waveguide components has the advantage that the optical waveguide component patterns are formed at a specified angle directly on the wafer, eliminating the separate processes of grinding and polishing the optical waveguide ends obliquely at a specified angle after cutting, and thus preventing a decrease in the yield of optical waveguide components. Also, productivity can be increased thanks to the reduction of the processing time and accordingly the production cost can also be reduced considerably.

Claims

1. A method of fabricating optical waveguide components comprising forming optical waveguide component patterns on 5 a wafer substrate by means of photolithography, the optical waveguide component patterns being formed obliquely at a specified angle (0) to vertical and horizontal scribe lines on the wafer.

2. A method according to claim 1 further comprising cutting the wafer along the horizontal and vertical scribe lines to form a plurality of optical waveguide components.

3. A method according to claim 1 or claim 2 in which the 15 said angle (e) is 1-20 degrees.

4. A method according to any preceding claim in which the optical waveguide component patterns are used as a silica optical waveguide element, a polymer optical waveguide 20 element or a photodetector element.

5. A method according to any preceding claim in which the wafer substrate is a silicon wafer, a gallium arsenide wafer, a lithium niobate wafer or a quartz wafer.

6. A method according to claim 2 or claim 3 f urther comprising connecting the optical waveguide components to with one or more optical fibres at the said angle (0).

7. A method according to claim 6 in which the said angle (0) is above the value of the numerical aperture (NA) inherent in the optical waveguide components and the optical fibres.

8. A method of fabricating optical waveguide components substantially as described herein with reference to and/or as illustrated in FIGs. 3-5 of the accompanying drawings.