GB2327773A

GB2327773A - Planar optical segmented waveguide for attenuation

Info

Publication number: GB2327773A
Application number: GB9815628A
Authority: GB
Inventors: Tae-Hyung Rhee
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1997-07-28
Filing date: 1998-07-20
Publication date: 1999-02-03
Anticipated expiration: 2018-07-20
Also published as: GB9815628D0; KR19990012249A; JPH11119042A; GB2327773B

Abstract

A planar waveguide device having a segment waveguide 120 to obtain equal splitting and equal output, comprises a segment waveguide having optical waveguide segments for generating a small optical signal intensity attenuation within a waveguide, to control waveguide output signal intensity and equalize the intensity of optical signals between waveguide output ports of the waveguide device fabricated on a single planar substrate. The segment waveguide and the waveguide 110 may be simultaneously fabricated. Planar substrate 110 is shown.

Description

PLANAR WAVEGUIDE DEVICE HAVING SEGMENT WAVEGUIDES BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to a planar waveguide device, and more particularly, to an optical planar waveguide having an equal splitting ratio or an equal output intensity between waveguide outputs on account of segment waveguides.

2. Description of the Related Art For the purpose of optical signal processing such as splitting, modulation, switching, multiplexing or equalization of an optical signal, much research has been made into optical device integration technology for fabricating an optical waveguide on a planar substrate using planar waveguide technology. Roughly three technologies of waveguide design, fabrication, and packaging are required to manufacture an optical waveguide for use in an optical communications system.

For some purposes, the optical waveguide device must make a waveguide asymmetrical or make the path distance different. When such a waveguide is fabricated or packaged, signal intensity attenuation or other losses such as signal attenuation necessarily occur. In this case, particularly, in the case of a waveguide using a Y-splitting point, the property of accurately controlling a splitting ratio is important. Also, in the case of a waveguide which uses the Y-splitting point and has an asymmetrical structure, the splitting ratio must be controlled artificially. In the prior art, there is no special technique capable of solving the above problems and suitable for mass production, so that the control of the splitting ratio was individually, manually accomplished. FIG. 1 shows an example of an asymmetrical optical waveguide, in which reference numeral 100 is a planar substrate and reference numeral 130 is an asymmetrical waveguide.

In the general fabrication of an asymmetrical optical waveguide device, each waveguide necessarily outputs a different optical signal due to a difference in the distance each optical signal travels or a difference in signal attenuation. Also, the optical waveguide device can have an unequal splitting ratio or a difference in For this, the segment waveguide 120 has a structure in which signal attenuation is generated between a waveguide and a waveguide segment which is nearest to the waveguide or between adjacent waveguide segments. Also, the segment waveguide 120 has a structure in which the tilt or off-set of an optical axis exists between a waveguide and a waveguide segment which is nearest to the waveguide or between adjacent waveguide segments.

A material such as cladding or a material having a smaller refractive index than a segment is used between segments or between a waveguide and a segment. In the waveguide device organized as described above, the signal attenuation is increased using the structure and arrangement of segments in the sequence of a waveguide having a highest output intensity, to control the output intensities of all waveguides. Also, the angle of the segment waveguide is controlled when necessary, to reduce the reflection loss generated by the segment waveguide. FIG. 4 shows an example of reducing the reflection loss in a waveguide by arbitrary processing on the angle. Here, reference numeral 140 denotes a segment having a predetermined angle 0 (0s8'20 ).

The waveguide and the segment waveguide are fabricated simultaneously by the same process.

According to the present invention, only a simple structure capable of attenuating an optical signal is added upon fabricating a waveguide, and the added structure and the waveguide are simultaneously fabricated, so that there is no need to have an additional process or provide additional accuracy to control the output intensity difference generated at an output waveguide port of an optical waveguide device. Also, additional processes or special efforts are not required for packaging and installation, and factors of cost increase upon fabricating a device performing an equivalent function can be eliminated.

FIG. 2 shows the structure of an asymmetrical optical waveguide device including waveguides having an equal splitting ratio, according to a preferred embodiment of the present invention; FIG. 3 shows the structure of a segment waveguide according to a preferred embodiment of the present invention; and FIG. 4 shows the structure of a waveguide including a segment waveguide angled to reduce reflection loss.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the present invention, a simple structure capable of attenuating an optical signal in fabrication of a waveguide is included in the waveguide. Also, the present invention equalizes the entire output intensity of every output waveguide while maintaining the same process and accuracy as in the prior art upon fabrication of a waveguide. Referring to FIG. 2, reference numeral 100 is a planar substrate, reference numeral 110 is a waveguide, and reference numeral 120 is a segment waveguide.

The segment waveguide 120 obtains an equal splitting ratio of waveguides or a uniform output intensity between waveguides by compensating for an unequal splitting ratio of a waveguide optical signal or a difference in output intensity between waveguides. The segment waveguide 120 is comprised of optical waveguide segments for generating small optical signal intensity attenuation within the waveguide. The optical waveguide segments can control output intensities at waveguide output ports of a waveguide device fabricated on a single planar substrate and equalize the intensity of optical signal between waveguide outputs.

In order to control the output intensity of each waveguide to within a predetermined range upon designing an asymmetrical waveguide, based on the output intensity of the lowest output waveguide, all or part of other waveguides are fabricated using the segment waveguide. FIG. 3 shows various structures of the segment waveguide 120. The attenuation degree of the output of a waveguide is controlled by the number of segments included in each waveguide, the interval between the segments in a waveguide, and the degree of distortion between the segments.

8. A planar waveguide device substantially as described with reference to the accompanying drawings.

Claims

What is claimed is:

1. A planar waveguide device which can control a splitting ratio of a waveguide or/and waveguide output intensities, comprising: a segment waveguide having optical waveguide segments for generating a small optical signal intensity attenuation within a waveguide, to control waveguide output signal intensities and equalize the intensity of optical signals between waveguide output ports of the waveguide device fabricated on a single planar substrate.

2. The planar waveguide device as claimed in claim 1, wherein the segment waveguide has a structure in which signal attenuation is generated between a waveguide and a waveguide segment that is nearest to the waveguide.

3. The planar waveguide device as claimed in claim 1, wherein the segment waveguide has a structure in which signal attenuation is generated between adjacent waveguide segments.

4. The planar waveguide device as claimed in claim 1, wherein the segment waveguide has a tilt or off-set in an optical axis between the waveguide and a waveguide segment that is nearest to the waveguide or between adjacent waveguide segments.

5. The planar waveguide device as claimed in claim 1, wherein the waveguide and the segment waveguide are simultaneously fabricated using an identical process.

6. The planar waveguide device as claimed in claim 1, wherein both ends or one end of the waveguide or at least one segment waveguide are slanted at a predetermined angle e (0sOs20 ).

7. The planar waveguide device as claimed in claim 1, wherein the number of segments of the segment waveguide is adjusted to control the signal intensity attenuation of an optical signal.