JPH0882767A - Optically functional parts - Google Patents

Abstract

PURPOSE: To provide optically functional parts easy to adjust optically, excellent in productivity, preventing a return beam from entering an optically functional element and showing a stable characteristic. CONSTITUTION: This optically functional parts have sticking type optical isolators 5a, 5b joined one or more of Faraday rotators and two or more of polarizers by adhesive material so that the transmission polarization directions of respective polarizers are positioned so as to be rotated relatively by a prescribed angle around an optical axis each other are arranged at connection parts between respective optical transmission lines 3a, 3b and the optically functional elements. Thus, the fluctuation in the characteristic of the optically functional elements due to a reflection return beam is prevented, and stable operation is attained, and further, by using the sticking type optical isolators 5a, 5b, the optically functional parts easy to adjust optically and excellent in productivity are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical isolator used for removing return light generated when light emitted from a light source or the like is introduced into an optical transmission line such as various optical elements, optical fibers or optical waveguides. And an optical functional component provided with an optical isolator.

[0002]

2. Description of the Related Art Conventionally, when light emitted from a light source such as a laser light source is made incident on various optical elements and optical fibers, a part of the incident light is generated on the end surfaces and inside of these various optical elements and optical fibers. It is reflected and scattered. Then, a part of the reflected and scattered light returns to the light source as return light and changes the light output emitted from the light source. An optical isolator is used to prevent this returning light.

Conventionally, in this type of optical isolator, a lithographic Faraday rotator is arranged between two polarizers, and these three components are housed in a cylindrical magnet via a component holder. I was making up. Here, normally, the Faraday rotator is configured to have a thickness that rotates the polarization plane of light of a predetermined wavelength by 45 ° in a saturation magnetic field, and the two polarizers have their transmission polarization directions shifted by 45 °. The rotation is adjusted.

In the optical isolator having such a structure, the Faraday rotator and the two polarizers are separate parts, and a holder is required for each element. Therefore, not only the number of parts increases and the number of assembling steps increases, but also each part increases. The optical adjustment work of is complicated.

[0005]

However, in the conventional coupling between the optical transmission line and the optical isolator or coupling between the optical functional element and the optical isolator, a condensing means such as a lens is used for the coupling. There was a need. Transmission lines such as optical fibers and optical waveguides used for optical communication, etc., have a very small portion where light propagates, on the order of a micrometer, so adjustment to introduce light into this transmission line is extremely difficult. Have difficulty. Moreover, in the conventional optical isolator,
Since it is necessary to adjust each element, the workability is poor, the assembly process is complicated, and there is a possibility that the forward loss may increase when the position shift occurs.

[0006]

SUMMARY OF THE INVENTION In order to solve these problems, the present invention provides one or more Faraday rotators and two or more polarizers in which the transmission polarization directions of the respective polarizers are relative to each other. In an optical functional component such as an optical isolator using a coupling element bonded with an adhesive so that the coupling element is rotated by a predetermined amount in the center, the coupling element is used as an optical transmission line such as an optical waveguide or an optical fiber and an optical package. Provided is an optical function component arranged between a coupling part with an optical function element.

[0007]

According to the structure of the present invention, by arranging the bonded element type optical isolator between the coupling portions of the optical transmission line and the optical function element, the optical axis adjustment at the coupling portions is simplified, and further, The reflected return light generated in the optical transmission line and the optical function element is removed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the basic structure of a bonded optical isolator. This is a configuration in which a Faraday rotation plate 2 made of a YIG crystal is arranged between two polarizing plates 1a and 1b in which a complex dielectric is dispersed in a dielectric. Although a magnet is not shown in this figure, in practice, an element for generating a magnetic field is laminated and is formed so as to surround the bonded element.

FIGS. 2 and 3 are specific examples of the present invention in which an optical package is used as an optical functional element, and are configuration diagrams in which a bonded optical isolator is provided. The optical package in this embodiment guides the incident light from the optical fiber to the light receiving portion of the OEIC (electro-optical integrated circuit) and further deflects the light emitted from the OEIC to the output side optical fiber such as a diffraction grating. It is composed of elements.

The optical signal incident from the input side optical fiber 3b passes through the microlens array 4b, the bonded optical isolator 5b, and is guided to the inside of the optical package. The optical signal 8 incident on the optical package is deflected by the deflecting element 6 and is incident on the light receiving portion on the OEIC 7. However, a part of the optical signal is reflected on the surface of the light receiving portion of the OEIC 7. In particular, when the incident optical signal is close to vertical incidence, the reflected optical signal 10 is
There is a risk of returning through the optical path close to the incident optical path and making reverse incidence on the incident side optical fiber.
No. 1 is removed by the bonded optical isolator 5b and is prevented from entering the incident side optical fiber 3b.

FIG. 4 is a schematic view of a specific embodiment according to the present invention when a semiconductor laser array is used as an optical functional element. This semiconductor laser becomes unstable in light emission when reflected return light is incident on the device. In the configuration of the present invention, the semiconductor laser array 15 and the optical waveguide 12 that is a transmission line are provided.
When the optical coupling is performed, the bonded optical isolator 13 is inserted in the coupling portion in order to remove the reflected return light.

The optical signal emitted from the semiconductor laser array 15 is condensed by the microlens array 14, passes through the bonded optical isolator 13, enters the optical waveguide 12, and is transmitted. On the other hand, the return light reflected or scattered during the transmission and transmitted in the direction opposite to the transmission direction or the return light reflected by the end face of the optical waveguide is removed by the bonded optical isolator 13 and the semiconductor laser array is removed. It cannot enter 15.

[0014]

As described above, according to the present invention, by using the bonded type optical isolator in the coupling portion between the optical transmission line and the optical function element, the fluctuation of the characteristics of the optical function element due to the reflected return light can be prevented. In addition, the bonded optical isolator can provide stable operation of the optical functional element, and further, because the optical adjustment of the bonded optical isolator is simple, it provides an optical functional component with excellent productivity. be able to.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a basic configuration of a bonded element of the present invention.

FIG. 2 is a schematic view showing a specific example of an optical package according to the present invention.

FIG. 3 is a schematic view showing a diagram for explaining a specific embodiment of the present invention.

FIG. 4 is a schematic view showing a specific example of a semiconductor laser array according to the present invention.

[Explanation of symbols]

 1a, 1b Polarizer 2 Faraday rotator 3a, 3b Optical fiber array 4a, 4b Microlens array 5a, 5b Bonding optical isolator 6 Deflecting element 7 OEIC 8 Incident optical signal 9 Deflected incident signal light 10 Reflection of signal light Return light 11 Reflected return light of deflected signal light 12 Optical waveguide 13 Bonding optical isolator 14 Microlens array 15 Semiconductor laser array 16 Electrode

Claims (1)

[Claims] 1. One or more Faraday rotators and two or more polarizers are bonded with an adhesive so that the transmission polarization direction of each polarizer is relatively rotated by a predetermined amount around the optical axis. In an optical functional component such as an optical isolator using a coupling element, the coupling element is arranged between a coupling portion between an optical transmission path such as an optical waveguide or an optical fiber and an optical functional element such as an optical package. Optical functional parts to do.