JPS6172206A - Substrate type waveguide and its production - Google Patents

Abstract

PURPOSE:To obtain a substrate type waveguide for single mode having a polarization plane maintaining property by laminating a stress giving layer, a core layer, and another giving layer successively on a substrate. CONSTITUTION:The stress giving layer 2, the core layer 3, the stress giving layer 4 are laminated successively on the substrate 1 consisting of quartz of silicon in the direction vertical to the surface of the substrate 1. Two V grooves 11 are formed in each of both ends of the substrate 1, and a constant polarization single mode optical fiber 12 is arranged in each V groove. A stress is applied to the core layer 3 in the direction vertical to the substrate surface by two stress giving layers 2 and 4, and the propagation constant in the axial direction of an optical signal propagated in the core layer 3 is varied to maintain the plane of polarization. Thus, a branching/coupling element having the polarization plane maintaining property for constant polarization single mode optical fibers is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a substrate type waveguide and a method for manufacturing the same.

(b) Prior art (Temporary waveguides have excellent productivity and stable characteristics. By the way, conventionally, fiber waveguides have been the main branching and coupling elements for optical fibers, especially , there are no substrate-type waveguides for medium-mode optical fibers.This is an element for splitting and coupling single-mode optical fibers, especially single-mode optical fibers with polarization preserving properties. This is because it has been difficult to realize a branching/coupling substrate-type waveguide with polarization preservation property, even though it is often required to have polarization preservation property.

(C) Objective The object of the present invention is to realize a substrate-type single-mode waveguide having polarization preservation properties and to provide a manufacturing method that can easily manufacture this waveguide.

(D) Structure The substrate-type waveguide according to the present invention has a structure in which a stress applying layer, a core layer, and a stress applying layer are sequentially laminated on a substrate in a direction perpendicular to the surface of the substrate.

Furthermore, the method for manufacturing a substrate type waveguide according to the present invention is as follows:
(A vapor phase deposition step in which a stress imparting layer, a core layer, and a stress imparting layer are successively deposited from a vapor phase on a board, and a stress imparting layer, a core layer, and a stress imparting layer formed on the substrate. and an etching step of etching the waveguide pattern according to the waveguide pattern.

(E) Example The substrate type waveguide according to the present invention is as shown in FIG.
A stress applying layer 2, a core layer 3, and a stress applying layer 4 are sequentially laminated on a quartz or silicon substrate I in a direction perpendicular to the surface of the substrate I. Two V-grooves 11 are formed at each end of the substrate 1, and a constant polarization single mode optical fiber 12 is disposed in each of the V-grooves. The two stress applying layers 2.4 apply stress to the core layer 3 in a direction perpendicular to the substrate surface, causing a difference in the propagation constant in the axial direction of the optical signal propagating through the core layer 3, thereby preserving the plane of polarization. be done.

In this way, a polarization-preserving branching/coupling element for a polarization-constant single-mode optical fiber is constructed.

Although omitted in FIG. 1, a thin film protective layer (see 5 in FIG. 3 G) is provided to cover and protect the stress applying layer 2, core layer 3, and stress applying layer 4. .

These stress-applying layers 2.4 and core layer 3 are formed by successively forming three layers of glass films of different materials on the substrate 1 using the CVD method (chemical vapor deposition method). After that, etching is performed to form a waveguide pattern. By manufacturing by such a method, the manufacturing process can be simplified, and the interface state between the stress applying layer 2.4 and the core layer 3 can be maintained in a good condition.

Specifically, for example, a CVD apparatus 6 as shown in FIG.
Use. This CVD apparatus 6 consists of a reaction vessel 61 and a heating device 62 arranged around the reaction vessel 61, and the reaction vessel 61 is provided with a source gas supply port 63 and an exhaust port 64. The substrate 1 is held within this reaction vessel 61 by a holder 65 .

In this example, a silicon wafer with a thermal oxide film is used as the substrate 1, and 5fC1*; 60cc is first used as the raw material gas.
/win, GeCl 4 ; 2cc/win, B
B r x; 12 cc/+*in 02; 20
00cc/min into a reaction vessel 61 heated to 1400°C, and as shown in FIG. 3A, a stress-applying layer ? S i 02- B 2
0 x -G e 02' glass layer at 2gm/wi
grown at n. This 5iOzB 20 m -G e
The 02 series glass layer is Sin,; 90%, B v O
The refractive index is 1.3 with a composition of 2% and GeOy of 8%.
It is 4585.

After this stress applying layer 2 has grown to a thickness of 18 pm, 5fCI4; 60cc7min, GeCI4
; 12cc/win, Oa; 2000cc/
lll1n, temperature 1450℃, Sin, -Ge
A core layer 3 of the -0, glass layer is grown to a thickness of 9 layers m in succession to the stress-applying layer 2, as shown in FIG. 3B. This S io, -Ge-02 glass layer is
S i O2; 87%, ' G e Ox ; l
The refractive index was 1.464 with M1 content of 3%.

Then, as shown in FIG. 3C, S 10 similar to the above is performed.
a - B 201 Q eo One layer 4 made of i-based glass was heated to a thickness of 18 g under the same conditions as above.
It was formed into m.

Glass film 2.3.4 of these three layers by CVD method is 3
After the layers are grown successively, a photoresist 71 is applied as shown in the third diagram, and then UV
A window 72 is formed according to the waveguide pattern by exposure. A mask layer 7 is formed on this window 72 by sputtering.
Photoresist 71 after depositing metallic titanium as 3.
(See Figure 3E) 1. Glass other than the waveguide pattern 1 Return 2 using CF4 as etching gas
．． 3 and 4 are removed by RIE (reactive ion competition etching) (see Figure 3F).

Next, as shown in FIG. 3G, an organometallic compound, in this example 5t (OC2H4
) is decomposed to form the protective layer 5 with tpm of J-blind Si.
oz layer was provided. +Silicon groove 11 for fixing the optical fiber 12 is provided at the tj4 end of the plate 1 by anisotropic etching as shown in FIG. It is as written in the figure.

(f) Effects According to this invention, the productivity is excellent and the characteristics are stable.
A substrate-type single mode waveguide having polarization preservation property is obtained. Further, according to the manufacturing method according to the present invention, the above substrate type single mode waveguide can be easily manufactured.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of an embodiment of the present invention, FIG. 2 is a schematic diagram of a CVD apparatus, and FIGS. 3A to 3G are cross-sectional views of each manufacturing process. l... Substrate 2, 4... Stress applying layer 3
...Core layer 5...Protective layer 6...CV
D device

Claims (2)

[Claims] (1) A substrate-type waveguide in which a stress-applying layer, a core layer, and a stress-applying layer are sequentially laminated on a substrate in a direction perpendicular to the surface of the substrate. (2) A vapor phase deposition step in which a stress imparting layer, a core layer, and a stress imparting layer are successively deposited from a vapor phase on a substrate, and the stress imparting layer, core layer, and stress imparting layer formed on the substrate are A method for manufacturing a substrate-type waveguide, comprising an etching step of etching a provision layer according to a waveguide pattern.