JPS6146801B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical device that performs optical demultiplexing or multiplexing, and has a simplified configuration.

Conventionally, as shown in Fig. 1, this kind of lens is equipped with wavelength-selective reflective surfaces 2, 4 on gradient index lenses (hereinafter referred to as lenses) 1, 3, and these surfaces 2, 4 are bonded together with the same lens. 2 of lens groups 5 and 6
The groups are arranged as shown in the figure, and the light enters the lens group 5 from the optical fiber 7 and is transmitted through the wavelength-selective reflecting surface 2, and then enters the optical fiber 8. Further, the light reflected by the reflective surface 2 enters the lens group 6, and the light is further divided into transmitted light and reflected light by the wavelength-selective reflective surface 4. The transmitted light is transmitted to the optical fiber 9, and the reflected light is transmitted to the optical fiber 10.
incident on .

Therefore, in this configuration there are at least 4 lenses.
In addition, it was necessary to provide four optical fibers for input and output, one at each end of each of the four lenses, which was complicated in terms of the number of parts and assembly.

The present invention obviates these drawbacks.
An embodiment shown in the drawings will be described below.

In FIG. 2, 11 and 13 are graded index lenses, 12 and 14 are wavelength-selective reflective surfaces, and 16 to 1
Reference numerals 9 indicate optical fibers, and 20 to 23 indicate optical paths. In this case, the transmitted three waves 24, 25, 26 as shown in FIG. 4 are combined, transmitted through one optical fiber 16 in FIG. Here, the optical path 20 passes through the wavelength selective reflecting surface 12 having the wavelength characteristic 27 shown in FIG.
4 is reflected, passes through the optical path 21, and enters the optical fiber 18. Wavelengths 25 and 26 are transmitted through the wavelength-selective reflecting surface 12, and the light with wavelength 25 is reflected by the wavelength-selective reflecting surface 14 having wavelength characteristics 28 shown in FIG. Transmitted and optical path 22
and enters the optical fiber 17. At this time, the wavelength-selective reflecting surface 14 is arranged at an angle α with respect to the wavelength-selective reflecting surface 12, and the optical paths 21, 22 of the wavelengths 24, 25 reflected and passing through the lens 11 are different, and the same surface Optical fibers 18, 17 arranged in
It is made so that it can be input to.

Wavelength 26 transmitted through the wavelength selective reflective surface 14
passes through the lens 13 through the optical path 23 and enters the optical fiber 19. In this way, the three wavelengths 24, 25, and 26 that were multiplexed can be separated and input into each optical fiber.

Although the above description has been given as a demultiplexer, it can be used as a multiplexer by reversing the optical paths 20, 21, and 23 in FIG. 2 (reversing the arrows) and replacing the input and output.

The core diameter of optical fibers currently in use is typically 50 to 60 μΦ, and the cladding diameter is typically 125 to 150 μΦ. The inclination of the wavelength-selective reflective surface 14 in FIG. 6 is θ
Let the length of the lens be L, and the optical fiber 16,1
If the interval between 7 and 18 is l, then L・tanθ/
The formula 2=l holds true. FIG. 7 shows the relationship between optical fiber deviation and optical loss in the x, y, and z directions, which was determined through experiments. From this, it is necessary to perform adjustments mainly in the x and y directions more precisely. Therefore, the accuracy of the inclination α of the wavelength-selective reflective surface 14 shown in FIG. 2 is required. FIG. 8 shows an example of the adjustment method. First, the optical fibers 16, 17, and 18 shown in FIG. It is fixed to the lens 11. Next, the slope α is adjusted so as to maximize the optical input of wavelength 25 incident on the fibers 16 to 17. Regarding the y direction in FIG. 6, an arm 32 is attached so as to increase the distance 31 of the jig in FIG.
Similarly, in the x direction, attach the arm 36 so as to increase the distance 35, and move the arrow 3 around the axis 37.
Adjust in 8 directions.

By repeating this adjustment in the x and y directions, the amount of light incident on the optical fiber 17 is maximized. Finally, the optical fiber 19 is fixed so that the light input of the wavelength 26 that enters the optical fiber 19 is maximized.

Also, in FIG. 3, normal lenses 11' and 1 are used instead of the gradient index lenses 11 and 13 in FIG.
3', a similar configuration can be achieved.

As explained above with reference to the embodiments, according to the present invention, the number of lenses is reduced to two, which is half that of the conventional example, and the number of connections for four optical fibers is also reduced to two, compared to the conventional example.
(Three on one side can be connected at the same time), which simplifies the number of parts and assembly.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional optical device, FIG. 2 is a block diagram of an optical device according to an embodiment of the present invention, and FIG.
The figure shows the configuration of another embodiment, Figure 4 shows the spectral characteristics of light, Figure 5 shows the characteristics of the transmission and reflection layers, Figure 6 shows the angle between the reflective surfaces, and Figure 7 shows the characteristics of the transmission and reflection layers. The optical loss characteristic diagram, FIG. 8, is a diagram showing the angle adjustment method. 11, 13... Lens, 12, 14... Wavelength selective reflective surface.

Claims (1)

[Claims] 1 A first lens with one input (or output) fiber and two output (or input) fibers in the focal plane on one side and a wavelength-selective reflective surface on the other side; A second lens is provided on one side of the focal plane, and the other side is a wavelength-selective reflecting surface, and the wavelength-selective reflecting surfaces of the first and second lenses are arranged to provide three outputs for one input. An optical device characterized in that the optical devices are arranged facing each other at an angle that separates (or combines three inputs into one output).