KR100468404B1 - Module for photo-transceiver - Google Patents

Abstract

The present invention provides a module for optical transmission and reception.

A light emitting device that emits light of a first wavelength, a light receiving device that receives light of a second wavelength, and light from the light emitting device is incident on an optical fiber, and the light from the optical fiber is inclined to face the light receiving device. In an optical transmitting / receiving module having an optical filter, the light emitting element, the optical filter, and the optical fiber are arranged substantially coaxially, and the light receiving element is disposed at a position where light from the optical fiber is reflected by the optical filter and guided. The end face of the optical fiber was inclined at a predetermined angle with respect to the optical axis of the optical fiber, and the inclined direction of the end face of the optical fiber was provided opposite to the inclined direction of the optical filter arranged inclined.

Description

Optical transmission module {MODULE FOR PHOTO-TRANSCEIVER}

The present invention relates to a module for optical transmission and reception, and to an optical transmission module that can be manufactured in a small size and at low cost.

There is a conventional optical transmitting / receiving module having an optical system shown in FIG. The light transmitting / receiving module 20 enters light of the wavelength n1 (for example, λ = 1310 nm) emitted from the laser diode 11, which is a light emitting element, into the optical fiber 12, and at the same time, the optical fiber 12 Light of the wavelength n2 (for example, lambda = 1550 nm) emitted from the light is received by the photodiode 13, which is a light receiving element.

In addition, the light transmitting / receiving module 20 is provided in close proximity to the laser diode 11 to close the first convex lens 21 for condensing light on the end surface of the optical fiber 12 and the photodiode 13. It is provided, and the 2nd convex lens 23 which condenses the light from the optical fiber 12 to the photodiode 13 is provided. Such an optical system includes a branching filter 24 disposed between the first convex lens 21 and the optical fiber 12 inclined at an angle of 45 degrees with respect to the optical axis. In this example, the branching filter 24 is formed by stacking a multilayer film on parallel optical glass.

In the optical transmission / reception module 20, the end surface 12a of the optical fiber 12 is configured to be inclined obliquely so that the emitted light from the laser diode 11 is not reflected back to the optical fiber 12 (Fig. In Fig. 16, the inclination angle and size are exaggerated.

According to the light transmitting / receiving module 20, the light having the wavelength n1 emitted from the light emitting element 15 of the laser diode 11 passes through the branch filter 24 through the first convex lens 21 and condenses. And enters the optical fiber 12.

In addition, the light of wavelength n2 emitted from the optical fiber 12 is reflected by the branching filter 24, is collected by the second convex lens 23, and enters the light receiving element 14 of the photodiode 13.

In the above-described conventional optical transmission / reception module, the light from the laser diode 11 is converged by the first convex lens 21, and the splitting filter 24 is applied while the converged light reaches the optical fiber 12. Permeate.

However, when the light in the converging state passes through the offset filter including the parallel optical glass inclined with respect to the optical axis, the transmission loss and the astigmatism loss occur and the coupling efficiency to the optical fiber is reduced. In this case, the reduction of the transmission loss can be achieved by implementing the antireflection means to improve the incident rate to the branching filter or by improving the material of the optical glass to lower the absorption rate. Coupling efficiency for optical fibers due to the difference in scores cannot be improved.

An object of the present invention is to provide a module for optical transmission and reception that can minimize the loss of coupling efficiency between a light emitting element and an optical fiber due to astigmatism of a branching filter.

1 is a diagram showing the configuration of an optical system of a module for optical transmission and reception according to an embodiment of the present invention;

FIG. 2 is a graph showing coupling efficiency values and aberration values of the optical system of the optical transmission / reception module shown in FIG. 1;

3 is a view for explaining each parameter of the graph shown in FIG. 2;

4 is a cross-sectional view showing a specific configuration of the module for optical transmission and reception shown in FIG. 1;

5 is a view showing a conventional optical transmission module.

※ Explanation of code in main part of drawing

11 laser diode 12 optical fiber

12a: end face 13: photodiode

14 light receiving element 15 light emitting element

21: convex lens 23: convex lens

24: Offset filter 30: Optical transmission module

31: end face 40: base body

41: sleeve

In this invention, in order to solve the said subject, the optical transmission module was comprised as follows. According to the present invention, a light emitting device emitting light of a first wavelength, a light receiving device receiving light of a second wavelength, and light from the light emitting device are incident on an optical fiber to incline the light from the optical fiber toward the light receiving device. An optical communication module having an optical filter arranged so that the light emitting element, the optical filter, and the optical fiber are arranged coaxially, and the light receiving element is disposed at a position where light from the optical fiber is reflected by the optical filter and guided. The end face of the optical fiber is inclined at a predetermined angle with respect to the optical axis of the optical fiber, and the inclined direction of the end face of the optical fiber is reversed to the inclined direction of the optical filter arranged inclined.

According to the present invention, the astigmatism caused by the optical filter disposed obliquely in the converging optical path can be canceled by entering the inclined end surface in the opposite direction to the inclined direction of the optical filter of the optical fiber, thereby reducing the coupling efficiency decrease for the optical fiber. You can.

In addition, the optical transmission module according to the present invention comprises a first optical element for converging the light of the first wavelength to the end surface of the optical fiber between the light emitting element and the optical filter, and the second optical element between the light receiving element and the optical filter A second optical element for converging light having a wavelength to the light receiving element is disposed.

According to the module for optical transmission and reception according to the present invention, the light of the first wavelength emitted from the light emitting element passes through the optical filter and is incident directly on the optical fiber by the first optical element, while the light emitted from the optical fiber is transmitted by the optical filter. Reflected and incident on the light receiving element.

In the module for optical transmission and reception according to the present invention, the first and second optical elements are aspherical lenses. According to the present invention using the above-mentioned aspherical lens, an optical system with little aberration can be realized with a minimum lens configuration, for example, one lens.

In the module for optical transmission and reception according to the present invention, the optical filter is used as a branching filter. According to the present invention using an optical filter as a branching filter, the first and second light having two wavelengths can be separated and received at the exit side and the incidence side, so that efficient signal transmission can be performed.

In the module for optical transmission and reception according to the present invention, it is assumed that the optical filter is a branching filter (for example, a half mirror divides the amount of light of the same wavelength), and the first wavelength and the second wavelength are the same wavelength. .

According to the present invention using an optical filter as a branch filter, time-division communication of the mutual communication, that is, communication between the forward and the reverse direction, can be performed sequentially by using an element that transmits and receives the light of the same wavelength, so that the same on both sides of the sorghum Optical devices can be used.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment which concerns on this invention is described based on an accompanying drawing. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing the configuration of an optical system according to an embodiment of a light transmitting / receiving module according to the present invention. Fig. 2 is a graph showing coupling efficiency values and aberration values of the optical system shown in Fig. 1, and Fig. 3 is a graph horizontal axis of Fig. 2. FIG. 4 which shows (theta) in FIG. 4 is a figure which shows the specific example of the module for optical transmission and reception which employ | adopted the optical system shown in FIG.

In the structure of the optical system shown in FIG. 1, light of the first wavelength (λ = 1310 nm) emitted by the laser diode 11 (the light emitting element is denoted by 15), which is a light emitting element, enters the optical fiber 12, and at the same time, the optical fiber The light of the second wavelength (λ = 1550 nm) emitted from (12) is incident on the photodiode 13 (representing a light receiving element 14) as a light receiving element. In addition, this wavelength can be bidirectionally communicated by changing each other at the incidence side and the exit side in the optical transmission / reception module.

In this example, the optical transmission / reception module 30 includes an aspherical convex lens 21 as a first optical element and an aspheric convex lens 23 as a second optical element between the laser diode 11 and the optical fiber 12. It is configured to include. These aspherical convex lenses 21 and 23 can realize a converging optical system with less aberration with one convex lens.

In this example, the inclination direction of the end face 31 of the optical fiber 12 is configured to be in the opposite direction to the inclination direction of the offset filter 24 in which the inclination is arranged. 3, the inclination direction of the branching filter 24 is shown by the arrow A, and the inclination direction of the end surface 31 of the optical fiber 12 is shown by the arrow B, as shown in FIG. In this example, arrow A is a vector whose end point is closer to the optical fiber at the branching surface of the branching filter 24 beyond the optical axis O. Similarly, the arrow B is the inclination of the end surface 31 of the optical fiber 12. A vector closer to the branching filter after the optical axis O in the direction is defined as a vector.

In this example, as shown in Table 1 and as shown in Fig. 2, when the rotation angles (θ in Fig. 3) between arrows A and B are 0 °, it was confirmed that the relative value of the coupling efficiency is maximum. (Table in Fig. 2). In addition, it was confirmed by the simulation of astigmatism that the minimum was obtained at an angle (θ = 0 °) (□ table in FIG. 2).

Review the results Measurement result Aberration Simulation Results Angle No filter With filter Coupling efficiency 0 2.758 2.537 92.0% 0.0719λ _RMS 30 2.630 2.250 85.6% 60 2.700 2.000 74.1% 90 2.700 2.200 81.5% 0.0935λ _RMS 120 2.650 2.066 78.0% 150 2.703 1.980 73.3% 180 2.730 1.975 72.3% 0.0959λ _RMS

Note: When the filter angle and the fiber inclined cut angle were opposite, the angle was 0 degrees and the same direction was 180 degrees.

As shown in Table 1 and FIG. 2, it is understood that excellent coupling efficiency can be obtained by configuring the inclined direction of the end face 31 of the optical fiber 12 in the opposite direction to the inclined direction of the branching filter 24.

4 shows a specific example of the optical transmission / reception module including the optical system described above. In this example, the optical system is accommodated in a base body 40 formed integrally with stainless steel. In addition, the optical fiber 12 has its end face inclined in a reverse direction with respect to the branching filter 24 by an installation sleeve 41 for the base body 40.

Moreover, in the said embodiment, although the wavelength of the light which received was made into another thing, it is possible to divide | communicate communication by time and to communicate by dividing alternately or a specific time by making these wavelengths the same.

Even in such a case, the present invention can cope with selecting the characteristics of the optical filter, for example, a branching filter for dividing a wavelength or a branching filter for splitting light having the same wavelength.

As described above, the optical transmission / reception module according to the present invention has the following excellent effects. The light emitting element, the optical filter, and the optical fiber are arranged coaxially, and the light receiving element is disposed at a position where light from the optical fiber is reflected by the optical filter and guided, and the end surface of the optical fiber is inclined at a predetermined angle with respect to the optical axis of the optical fiber. At the same time, according to the present invention in which the inclined direction of the end face of the optical fiber is reversed to the inclined direction of the optical filter inclined, the astigmatism caused by the optical filter inclined in the converging optical path is inclined in the inclined direction of the optical filter. It can cancel by making it enter the inclined end surface in the reverse direction, and it can reduce the coupling efficiency fall with respect to an optical fiber.

Further, a first optical element for converging light of a first wavelength on the optical fiber end surface is disposed between the light emitting element and the optical filter, and light of a second wavelength is converged on the light receiving element between the light receiving element and the optical filter. According to the present invention in which a second optical element is arranged, light of the first wavelength emitted from the light emitting element passes through the optical filter and is incident directly to the optical fiber by the first optical element, while light emitted from the optical fiber is the optical filter. By reflecting by the light incident to the light receiving element can be reduced the score of the optical element.

According to the present invention using the above-mentioned aspherical lens, an optical system with little aberration can be realized with a minimum lens configuration.

In addition, according to the present invention using an optical filter as a branching filter, the first and second light having two wavelengths can be separated and received at the exit side and the incident side, whereby efficient signal transmission can be performed.

According to the present invention, in which the optical filter is a branch filter and the optical transmission and reception of the same wavelength is performed, time division of the mutual communication, that is, communication between the forward and reverse directions, is sequentially performed using an element that receives light of the same wavelength. The same optical device can be used on both sides of the sorghum.

Claims (5)

A light emitting device that emits light of a first wavelength that is outgoing light, a light receiving device that receives light of a second wavelength that is receiving light, and light from the light emitting device is incident on an optical fiber to direct light from the optical fiber toward the light receiving device In the optical transmission module having an optical filter arranged inclined, The light emitting element, the optical filter, and the optical fiber are arranged coaxially, Arranging the light receiving element at a position where light from the optical fiber is reflected by the optical filter and guided; And inclining the end surface of the optical fiber at a predetermined angle with respect to the optical axis of the optical fiber, and making the inclination direction of the optical fiber end surface opposite to the inclination direction of the arranged optical filter. The method of claim 1, A first optical element for converging the light of the first wavelength to the end surface of the optical fiber is disposed between the light emitting element and the optical filter, and the light of the second wavelength to the light receiving element between the light receiving element and the optical filter. And a second optical element for converging. The method of claim 2, And said first and second optical elements are aspheric lenses. The method according to any one of claims 1 to 3, And said optical filter is a branching filter. The method according to any one of claims 1 to 3, And said optical filter is a branching filter, and said first wavelength and said second wavelength are the same wavelengths.