JPS62196620A - Laser module - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] A laser module of a light source of an optical communication device, in which both end surfaces of a Faraday rotator of an optical isolator constituting the laser module through which light passes are processed into spherical surfaces to function as lenses. In addition to improving the coupling efficiency between the optical fiber and the laser element, it also aims to reduce the size of the laser module.

[Industrial application field]

The present invention relates to a laser module, and more particularly, to a laser module in which a Faraday rotator of an optical isolator constituting the module is provided with a lens function to increase the coupling efficiency between a laser element and an optical fiber and to reduce the size of the module.

The optical fiber-attached laser diode module used for ultra-high-speed modulation is a Dtstributed-FeedBa that has a diffraction grating function in the active region that emits laser light.
ck-Laser (hereinafter referred to as DFB laser) is widely used.

The oscillation of this DFB laser tends to become unstable due to reflected light, and to prevent this, an optical isolator consisting of a polarizing prism, Faraday rotator, etc.
A laser module is constructed by inserting it between a laser element and an optical fiber.

By the way, when such an optical isolator is inserted between the laser element and the optical fiber, the coupling efficiency between the laser element and the optical fiber decreases, which makes it necessary to operate the laser element at a high output, thereby reducing the power of the laser element. Lifespan decreases.

Such optical communication devices are required to be more and more miniaturized, and the lifespan of the laser element is also required to be maintained for a long time.Therefore, there is a demand for a small laser module with high coupling efficiency. .

[Conventional technology]

A cross-sectional view showing the structure of a conventional laser module is shown in FIG.

As shown in the figure, the conventional laser module includes a DFB laser element 1, a stem 3 in which is installed a ball lens 2 that converts the light emitted from this laser element 1 into almost parallel light, and a laser emitted from this laser element 1. A polarizing prism 4 that passes only a single polarized light, a Faraday rotator 5 made of YIG (indolium-iron-garnet), and an optical isolator 7 that integrates a polarizing prism 6; It is composed of a condensing lens 8 that condenses the light that is transmitted, and a fiber fixing holder 10 in which an optical fiber 9 is installed.

Furthermore, the polarizing prisms 4 and 6 constituting the optical isolator 7 are installed in prism holders 11 and 12, respectively, and a magnet 13 is installed around the Faraday rotator 5.

The stem on which the laser element 1 is installed, the optical isolator 7, and the optical fiber holder 1O are each connected using a solder layer 14 or the like.

[Problem that the invention seeks to solve]

By the way, as mentioned above, such laser modules are required to be further miniaturized in order to miniaturize optical communication devices, and accordingly, it is necessary to reduce the number of optical components that make up the laser module. It is requested.

[Means for solving problems]

In the laser module of the present invention, both end surfaces of the Faraday rotator 25 constituting the laser module through which light passes are processed into spherical surfaces so that the Faraday rotator 25 has a function as a lens.

[Effect]

In the laser module of the present invention, both end surfaces of the Faraday rotator 25 of the optical isolator 27 constituting the laser module are processed into spherical surfaces through which light passes, so that the Faraday rotator 25 has a function as a lens, and the optical isolator 27 and this light A condensing lens as in a conventional laser module is not required between the optical fiber 29 that introduces the light emitted from the isolator 27.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a laser module of the present invention.

As shown in FIG. 1, the laser module of the present invention includes a DFB laser element 21, a stem 23 incorporating a ball lens 22 that makes laser light emitted from this element substantially parallel, and a polarized light beam. A prism 24, a Faraday rotator 25 whose both end surfaces through which light passes are processed to have a lens function, an optical isolator 27 in which a polarizing prism 26 is installed, and an optical fiber 29 installed in an optical fiber fixing holder 28. It becomes more.

This polarizing prism 24 is installed in a prism holder 30 , a magnet 31 is installed around a spherically processed optical isolator 25 , and the polarizing prism 26 is installed in a prism holder 32 .

Further, the stem 23 on which the laser element 21 is installed, the optical isolator 27 and the optical fiber holder 28 are connected using a solder layer 33, respectively.

Here, the laser module of the present invention is different from conventional laser modules in that the Faraday rotator 25 constituting the optical isolator 27 has both end surfaces through which light passes are processed into spherical surfaces, so that it functions as a lens. The reason lies in the fact that it supports

Therefore, unlike the conventional laser module shown in FIG. 2, there is no need for a condensing lens 8 for condensing the light emitted from the optical isolator 7 onto the optical fiber 10, and the number of parts is reduced accordingly. It becomes a small laser module.

Further, since the laser module is miniaturized, the distance between the laser element 21 and the light incident end face of the optical fiber 29 is shortened, so that the coupling efficiency between the laser element and the optical fiber is increased.

〔Effect of the invention〕

As described above, according to the laser module of the present invention,
The formed laser module can be made smaller, and an optical communication device using this laser module can be made smaller.

Further, there is an effect that a laser module with improved coupling efficiency between the laser element and the optical fiber can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a laser module of the present invention, and FIG. 2 is a sectional view of a conventional laser module. In the figure, 21 is a laser element, 22 is a ball lens, 23 is a stem, 2
4.26 is a polarizing prism, 25 is a Faraday rotator, 27 is an optical isolator, 28 is a holder, 29 is an optical fiber, 30.32 is a prism holder, 31 is a magnet, and 33 is a solder layer.

Claims (1)

[Claims] A laser element (21), an optical isolator (27) composed of a polarizing prism (24, 26), and a Faraday rotator (25), and a laser beam that passes through the optical isolator (27) and is emitted. An optical fiber that introduces light and brings it out to the outside (
29), characterized in that both end surfaces of the Faraday rotator (25) through which light passes are processed into spherical surfaces, so that the Faraday rotator (25) has a function as a lens. laser module.