JP2755274B2 - Waveguide type light receiving module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device having a waveguide and a light receiving element, and more particularly to a waveguide type light receiving module having a fixed structure of the waveguide and the light receiving element.

[0002]

2. Description of the Related Art Conventionally, as an optical device having a waveguide and a light receiving element, a waveguide type optical multiplexer / demultiplexer for a bidirectional transmission module having the structure shown in FIG. 3 (Uesuka et al., 1991 IEICE Fall Meeting C201). And a quartz-type waveguide-type bidirectional transmission module having the structure shown in FIG.
7).

Referring to these drawings, in a conventional module, a light receiving element and a waveguide are generally arranged independently of each other.

For example, referring to FIG. 3, an LD element 10 is disposed on the inner wall of a stem 9 and a non-contact type waveguide type multiplexer / demultiplexer 1 is provided.
1 has a structure in which light emitted from the light source 1 is applied to almost the center of the LD element 10. Light enters the waveguide type multiplexer / demultiplexer 11 through an optical fiber 13, and light from the LD element 10 is emitted to the outside via the PD element 12 and the optical fiber 13. These components 10 to 13 are housed in a package 14 and block external light.

The quartz waveguide type bidirectional transmission module shown in FIG. 4 has a substantially similar structure. That is, the LD element 15
And a quartz-based waveguide 17 are opposed to each other via a pair of lenses 16, a PD element 18 is arranged on the incident side of the waveguide 17, and these components are accommodated in a package 19.

[0006]

In such a conventional structure, the waveguide and the light receiving element are both independent of each other. Therefore, in order to optimize the coupling efficiency of the two, the mutual positional relationship must be determined. It had to be precisely adjusted based on the axis. For this reason, there has been a problem that automation and mass production cannot be performed, and costs increase.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a waveguide type light receiving module having a structure that enables mass production and cost reduction by automation.

[0008]

According to the present invention, there is provided a waveguide type light receiving module having a structure in which a light receiving element is arranged on an optical axis of light emitted from the end of a waveguide formed on a substrate surface. The end face of the waveguide was formed obliquely so that light was emitted from the waveguide along the surface of the substrate on the side of the waveguide, and the light guide was provided on the end face of the waveguide. A total reflection surface and a light receiving surface of the light receiving element are provided on the substrate surface on the side of the waveguide, and light reflected by the total reflection surface is emitted from the waveguide. A groove for holding the light receiving element so as to be located;
A waveguide electrode provided adjacent to the groove on the substrate surface on the side of the waveguide and electrically connected to the light receiving element held in the groove. A type light receiving module is obtained.

Further, according to the present invention, the fixing of the light receiving element to the substrate and the electrical connection between the waveguide electrode and the light receiving element on the substrate are performed by using an Au-S formed on the light receiving element.
n The waveguide type light receiving module is obtained by melting the bumps.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing the structure of a waveguide type light receiving module according to an embodiment of the present invention, wherein 1 is a Si substrate, 2 is a cladding layer, 3 is a core layer, 4 is a light receiving element, and 5 is a guide groove. , 6 indicate waveguide electrodes.

The waveguide is formed on a Si substrate 1 with a cladding layer 2 of SiO 2 and a core layer 3 of TiO 2 -SiO 2.

As shown in FIG. 1, the end of the waveguide is a diagonally cut total reflection surface, and light transmitted via an optical fiber or the like (not shown) reflects the total reflection surface. The light is reflected and emitted from the side of the waveguide.

On the Si substrate 1 on the side of the waveguide in the light emission direction, a guide groove 5 for fixing the light receiving element 4 and an electrode 6
Are provided. The guide groove 5 is a groove having an inner diameter slightly larger than the outer shape of the light receiving element 4, and is processed by, for example, reactive ion etching. The depth and position of the guide groove 5 are set such that the light emitted from the waveguide enters the center of the light receiving surface 7 when the light receiving element 4 is inserted and fixed.

FIG. 2 is a diagram for explaining a connection process between the light receiving element 4 and the waveguide electrode 6 of the light receiving module according to the present embodiment.
(A) shows the state before connection, and (b) shows the state after connection.

In these figures, the hatched portion is a conductor portion, and 8 is an A formed on the light receiving element 4.
u-Sn bumps.

The fixing of the light receiving element 4 on the Si substrate 1 and the electrical connection between the waveguide electrode 6 and the light receiving element 4 are performed by reflowing the Au-Sn bump 8 in the state of FIG.
This is performed by melting as shown in (b).

[0018]

As described above, in the waveguide type light receiving module of the present invention, the guide groove is provided on the substrate so that the light receiving element is arranged at the position where the light is emitted from the waveguide.
Since the light receiving element is mechanically inserted into the guide groove, an efficient coupling can be easily achieved without adjusting the optical axis separately.

When fixing the light receiving element to the substrate and electrically connecting the waveguide electrode and the light receiving element, Au-Sn
Since the bumps are melted in the reflow process, the fixing and connecting operations are simplified and simplified. Therefore, automation of the manufacturing process is facilitated, and mass production and the resulting cost reduction become possible.

[Brief description of the drawings]

FIG. 1 is a structural perspective view of a waveguide type light receiving module according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating a connection process between a light-receiving element and a waveguide electrode of the light-receiving module according to the present embodiment.
(B) shows the state after connection.

FIG. 3 is a structural view of a waveguide type optical multiplexer / demultiplexer for a bidirectional transmission module as a conventional example.

FIG. 4 is a structural diagram of a quartz waveguide type bidirectional transmission module as a conventional example.

[Explanation of symbols]

 Reference Signs List 1 Si substrate 2 Cladding layer 3 Core layer 4 Light receiving element 5 Guide groove 6 Electrode 7 Light receiving surface 8 Au-Sn bump 9 Stem 10, 15 LD element 11 Waveguide type multiplexer / demultiplexer 12, 18 PD element 13 Optical fiber 14, 19 Package 16 Lens 17 Quartz Waveguide

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 31/02 H01L 31/10 G02B 6/10

Claims (2)

(57) [Claims] 1. A waveguide type light receiving module having a structure in which a light receiving element is arranged on an optical axis of light emitted from a terminal end of a waveguide formed on a substrate surface, wherein the light receiving element is disposed on a side of the waveguide. As light is emitted from the waveguide along the surface of the substrate, the end face of the waveguide is formed obliquely by forming the end face of the waveguide obliquely, and the total reflection surface provided on the end face of the waveguide, The light receiving element is provided on the side surface of the substrate, and holds the light receiving element such that the light receiving surface of the light receiving element is positioned on the emission surface of the waveguide from which the light reflected by the total reflection surface exits from the waveguide. A groove, a waveguide electrode provided adjacent to the groove on the substrate surface on the side of the waveguide, and electrically connected to the light receiving element held in the groove. Waveguide type light receiving module. 2. The fixing of the light receiving element to the substrate and the electrical connection between the waveguide electrode on the substrate and the light receiving element are performed by melting an Au—Sn bump formed on the light receiving element. The waveguide type light receiving module according to claim 1, wherein: