JP2530744B2 - Light module - Google Patents

Description

The present invention relates to an optical module such as an optical transceiver module used in the field of optical fiber communication, and an optical fiber and a package for the purpose of providing an optical module which can be hermetically sealed in good condition and is easy to manufacture. In an optical module optically coupled with an optical semiconductor chip arranged inside, an opening is provided in the package facing the optical semiconductor chip, and the opening is sealed with a flange member having a sapphire window. A flat sliding surface is formed on the flange member, and a fiber assembly holding the optical fiber is closely fixed to the sliding surface.

TECHNICAL FIELD The present invention relates to an optical module such as an optical transceiver module used in the field of optical fiber communication.

Optical fiber communication is performed by the transmitter side using electric power such as a semiconductor laser.
Modulates the light from the light conversion element, such as intensity modulation,
This modulated light is transmitted to the receiving side via an optical fiber, and the receiving side uses a photo-electric conversion element such as a photodiode to convert the received light into an electrical signal for information transmission. Is. The transmitter-side electro-optical conversion element and the reception-side optical-electrical conversion element must be optically coupled to the optical fiber, and in order to ensure high-speed operability, a drive circuit, an amplifier circuit, etc. It needs to be connected at a position close to the electronic circuit. Therefore, on the transmitting side, an optical transmitting module in which the electro-optical converting element and its driving circuit are housed in the same package is used, and on the receiving side, the amplifying circuit of the opto-electric converting element is the same. The optical receiving module housed in the package is used. Depending on the case, an optical transceiver module having these functions is used. In this type of optical module, a bare chip is often mounted in the package as it is because of the need for a high-speed electronic circuit, and therefore the package needs to be hermetically sealed.

Prior Art FIG. 4 shows an example of a conventional optical module. The package 2 is opposed to the optical semiconductor chip 4 having the photoelectric conversion function or the photoelectric conversion function arranged in the package 2.
An opening 2a is formed in the opening, and the opening 2a is closed by a sapphire window 6. Reference numeral 8 denotes a fiber assembly fixed to the outside of the package 2. The fiber assembly 8 inserts and fixes an optical fiber 10 in a ferrule 12, and the ferrule 12 is inserted and fixed in a pipe member 16 in which a lens 14 is press-fitted and fixed. Is configured. When the optical semiconductor chip 4 is an optical-electrical conversion element, the optical fiber 10
The light radiated from the end face of is converged by the lens 14 and transmitted through the sapphire window 6 to enter the optical semiconductor chip 4.
On the other hand, when the optical semiconductor chip 4 is an electro-optical conversion element, the light emitted from the optical semiconductor chip 4 passes through the sapphire window 6 and is converged by the lens 14 to form the optical fiber 10.
Incident on.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention By the way, in order to prevent deterioration of communication quality due to reflected light generated in the sapphire window 6 or the like, the sapphire window 6 is usually used with an antireflection film. If an antireflection film is formed on the sapphire window in advance, the package 2
The method of joining the sapphire window 6 to the is limited. That is, since the antireflection film is vulnerable to heat, when the antireflection film is formed on the sapphire window in advance, the sapphire window 6 is not attached to the package 2.
However, it is necessary to use low melting point solder such as AuSn solder. However, AuSn
It is difficult to achieve good airtight sealing when joining minute parts with solder or the like. Therefore, it may be proposed to bond the sapphire window 6 to the package 2 by silver brazing and then form the antireflection film on the sapphire window. With difficulty.

The present invention was created in view of such circumstances,
An object of the present invention is to provide an optical module which can be hermetically sealed and is easy to manufacture.

Means for Solving the Problems According to the present invention, in an optical module formed by optically coupling an optical fiber and an optical semiconductor chip arranged in a package, an opening is formed in the package facing the optical semiconductor chip. The opening is sealed with a flange member to which a sapphire window is joined, a flat sliding surface is formed on the flange member, and a fiber assembly holding the optical fiber is closely fixed to the sliding surface. The sapphire window is joined to the flange member by a high melting point wax material, and the opening of the opening is sealed by the flange member by joining the flange member to the package by a low melting point solder. An optical module is provided in which an antireflection film is formed on the optical module.

Operation According to the above-mentioned configuration, the opening of the package is sealed by the flange member having the sapphire window, and the fiber assembly is closely fixed to the flat sliding surface of the flange member. Even if the antireflection film is applied to the sapphire window after joining by good brazing, for example, silver brazing, formation of the antireflection film is not complicated. In this case, joining of the flange member to the package is limited to low melting point solder or the like so as not to damage the already formed antireflection film, but the joining area of the flange member and the package should be easily increased. Therefore, even if a low melting point solder or the like is used, good hermetic sealing is possible. In the configuration of the present invention, the flat sliding surface is formed on the flange member, and the fiber assembly is closely fixed to the sliding surface because the fiber assembly is fixed to the sliding surface prior to the fixing. This is because sliding allows the optical axis to be adjusted in the direction perpendicular to the optical path.

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

FIG. 3 is a perspective view of an optical receiver module showing an embodiment of the present invention, and FIG. 1 is a sectional view of an optical coupling portion thereof. 22 is a package made of metal or the like, and the inside is a partition plate 22a.
It is divided into two parts by. A flange member 30 described later is fixed to the side surface of the package 22, and a printed wiring board 24 in which an electronic circuit such as a front end amplifier is realized is provided on the flange member 30 side in the package 22.
A printed wiring board 26 having a power supply circuit and the like is mounted on the side of the package 22 opposite to the flange member 30. 28 is a lead terminal for external connection of the printed wiring board.

As shown in FIG. 1, an optical semiconductor chip 32 such as a photodiode is arranged inside the package 22 via a chip carrier 34. In this embodiment, the chip carrier 34 is provided to prevent reflection on the light receiving surface. Is package 22
Is provided obliquely to the side plate of the. An opening 22a is formed in a portion of the package 22 facing the optical semiconductor chip 32, a cylindrical portion of the flange member 30 is fitted into the opening 22a, and the flange of the flange member 30 is made of a low melting point solder such as AuSn solder. It is joined to the package 22. Inside the flange member 30, a sapphire window 36 is provided facing the optical semiconductor chip 32, and the sapphire window 36 is provided with an antireflection film. Reference numeral 38 denotes a fiber assembly closely fixed to the flat sliding surface 30a of the flange member 30, and the fiber assembly 38 includes a ferrule 42 in which an optical fiber 40 is inserted and fixed and a pipe member 46 in which a lens 44 is press-fitted. It is configured by inserting and fixing.

A procedure for manufacturing the optical coupling part shown in FIG. 1 will be described. First, the sapphire window 36 is silver brazed inside the flange member 30. At this time, since the sapphire window 36 is not yet provided with the antireflection film, silver brazing can be performed at high temperature. By joining the sapphire window 36 to the flange member 30 by silver brazing, a good hermetic seal of the joint is achieved. Then, an antireflection film made of a dielectric multilayer film or the like is formed on the sapphire window 36 joined to the flange member 30 by means such as vapor deposition. Thereafter, the flange member 30 is joined to the package 22 with a low melting point solder such as AuSn solder. Although the airtightness of the joint made of low melting point solder is inferior to that of the joint made by silver brazing, good airtightness can be obtained by increasing the area of the joint of the flange member 30 and the package 22. Is possible. The performance of the antireflection film already formed on the sapphire window 36 does not deteriorate due to the thermal effect at the time of joining with the low melting point solder. After that, the flange of the fiber assembly 38 configured as described above is brought into close contact with the sliding surface 30a of the flange member 30, and in this state, the fiber assembly 38 is moved in a plane perpendicular to the optical path so that the optical axis Adjustment is performed and the fiber assembly 38 is fixed to the flange member 30 by, for example, laser welding in a state where the maximum optical coupling efficiency is obtained. As described above, according to this embodiment, the package 22 can be hermetically sealed in good condition, and the manufacturing work is not complicated. In the case of the conventional technique, it was necessary to set the reference surface of the optical system on the entire side surface of the package 22, so that highly accurate processing was required for the package, but in the case of the present embodiment, the reference surface of the optical system is Since it can be set on the sliding surface 30a of the flange member 30, the area of the portion that requires highly accurate processing can be small.

By the way, since the chip carrier 34 on which the optical semiconductor chip 32 is mounted is minute, it is difficult to set the chip carrier 34 obliquely with respect to the package side plate as in the embodiment shown in FIG. Accompanied by sex. Therefore, in such a case, as shown in FIG.
Is arranged in parallel with the side plate of the package 22 and the sapphire window 36, and by using the flange member 30 ′ whose sliding surface 30a ′ is not parallel to the sapphire window 36, it is possible to prevent reflection on the light receiving surface. Good. Since the flange member 30 'is larger than the chip carrier 34, its sliding surface 30'
It is easy to form a'obliquely. This further simplifies the manufacture of the optical receiver module.

In the embodiment described above, the light receiving module in which the light receiving element is used as the optical semiconductor chip is configured, but the present invention is similarly applied to the light transmitting module using the light emitting element as the optical semiconductor chip. It can be carried out.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to provide an optical module that can perform good hermetic sealing and is easy to manufacture.

[Brief description of drawings]

1 is a sectional view of an optical coupling portion of an optical module showing an embodiment of the present invention, FIG. 2 is a sectional view of an optical coupling portion of an optical module showing another embodiment of the present invention, and FIG. FIG. 4 is a perspective view of an optical module (excluding a portion corresponding to a lid) showing the embodiment of FIG. 22 ... Package, 22a ... Opening, 30,30 '... Flange member, 30a, 30a' ... Sliding surface, 32 ... Optical semiconductor chip, 40 ... Optical fiber.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kaoru Moriya Kaoru Moriya 1015 Kamitadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited (56) References JP 64-10685 (JP, A) (JP, U)

Claims (2)

(57) [Claims] 1. An optical module in which an optical fiber and an optical semiconductor chip arranged in a package are optically coupled to each other, and an opening is formed in the package so as to face the optical semiconductor chip, and the opening is a sapphire window. Is sealed with a flange member joined to, a flat sliding surface is formed on the flange member, and the fiber assembly holding the optical fiber is closely fixed to the sliding surface. The flange member is joined with a high melting point wax material, the opening of the opening is sealed with the flange member by joining the flange member to the package with a low melting point solder, and an antireflection film is formed on the sapphire window. An optical module characterized by being used. 2. The optical module according to claim 1, wherein a sliding surface of the flange member is formed obliquely with respect to a surface of the optical semiconductor chip perpendicular to an incident optical path or an outgoing optical path. .