JPS61219924A - Optical module and optical terminal station - Google Patents

Abstract

PURPOSE:To attain a bypass function and a loop-back function by a simple constitution by attaching an optical signal receiving part and an optical signal transmitting part to a part of optical fibers and other optical fibers, respectively, in optical fibers which are attached to the end faces of a pair of focusing rod lenses. CONSTITUTION:Glass blocks 7, 7' are rotated by 180 deg. as indicated with an arrow 12. As a result, an optical signal which is propagated from an arrow 17 through an optical fiber 1 is reflected by an interference film filter 8 through a focusing rod lens 6, propagated as indicated with an arrow 18 through an optical fiber 2 after passing through the lens 6, reflected by a filter 8' through a lens 6' and a block 7', propagated through an optical fiber 1' in the direction as indicated with an arrow 19 through the block 7' and the lens 6' and a bypass function is attained. When the optical fiber 1' is disconnected and an optical signal from an optical signal transmitting part 4 cannot be sent to other terminal station, an optical signal from a semiconductor light emitting element 10 is sent into the optical fiber 1 and transmitted to other terminal station. When the optical fiber 1 is disconnected, an optical signal from other terminal station is received by a photodetector 11 through the optical fiber 1' and a loop-back function is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a highly reliable system having a bypass function and a loopback function in a loop optical network system.

[Background of the invention]

Conventionally, in a loop optical network system, for example, as described in Japanese Patent Application Laid-open No. 111105/1982,
In order to ensure the reliability of the entire system, a bypass function and a loopback function are provided to automatically maintain the system in the event of a failure.

FIG. 1 shows a schematic diagram of a conventional loop optical network system having a bypass function. This is an example in which four terminal stations are connected by optical fibers 1.1' and 1.1. The terminal station 5 consists of an optical signal transmitting section 4, an optical signal receiving section 3, a bypass transmission line 2, and a bypass switching optical switch 50. or when a failure occurs in the optical signal transmission section, the optical switch 50, 50' switches from A to B, and from A' to B', and sends the optical signal 15 through the bypass transmission line 2 to the optical fiber. 1'. In order to provide such a bypass function, an optical switch is required, but the optical switch is currently very expensive, and the benefits of using light are lost. In order to provide a loopback function, an optical signal receiving section is installed in the optical signal transmitting section of the terminal station 5.
The problem is that the cost of the entire system is extremely high due to the large number of optical devices (0 or more) and complex configurations in which optical signal transmitting units are provided separately for each optical signal receiving unit and a configuration for switching between them is added. There is a point.

[Purpose of the invention]

An object of the present invention is to provide a new optical module for a loop network system and an optical terminal station that can realize a bypass function and a loopback function with a simple configuration.

[Summary of the invention]

The present invention comprises an optical module consisting of a semiconductor light emitting element, a lens, a glass block with an interference film filter having an angular displacement function, a focusing rod lens, and three optical fibers A, B, and C attached to the end face of the lens. , an optical module using a semiconductor light-receiving element instead of the semiconductor light-emitting element (
Fiber optic beam.

Let them be E and F. ), an optical signal receiver is attached to the other end of the optical fiber A, an optical signal transmitter is attached to the other end of the optical fiber F, and the other ends of the optical fibers C and D are connected. B and C have two wavelengths λ1. The present invention is an optical module and an optical terminal station for a loop optical network system having bypass and loopback functions for bidirectional transmission of a λ2 optical signal.

[Embodiments of the invention]

FIG. 2 shows an embodiment of the optical terminal station of the present invention. This corresponds to section 5 in FIG. 1 and has a bypass function and a loopback function. In the same figure.

10 is a semiconductor light emitting element whose emission wavelength is λ2, and 11 is a wavelength λ
2, a light receiving element that receives the optical signal; 9 and 9' are ball lenses;
6.6' is a focusing rod lens whose length is slightly shorter than 1/4 pitch, 7 and 7' are glass blocks, and 8.8' has characteristics as shown in Figure 4 (a) or (b). An interference film filter having an interference film filter, that is, transmitting an optical signal of wavelength λ2,
A filter having a characteristic of reflecting an optical signal of wavelength λ1,
1゜1', 13.14 are transmission optical fibers, 2 is a bypass optical fiber transmission line, 3 is an optical signal receiving section that receives an optical signal of wavelength λ1, and 4 is a light that emits an optical signal of wavelength λ□. Signal transmitter, arrow 12 indicates glass block 7.7' 18
Arrows 15, 15', and 16, 16' indicate the direction of rotation of the mechanical part (not shown) that rotates 0a, arrows 15, 15', and 16, 16' indicate the flow direction of the optical signal during normal operation, and arrows 17, 18, and 19 indicate the direction of flow of the optical signal during bypass. Arrow 20. indicates the flow direction of the optical signal.
21 is an arrow indicating the flow direction of the optical signal during loopback. First, we will discuss normal operation. An optical signal (wavelength λ1) propagating within the optical fiber 1 as indicated by an arrow 15 passes through a convergent rod lens and enters the interference film filter 8. Since this interference film filter 8 is formed at a desired inclination angle θ with respect to the glass block 7, the above-mentioned incident optical signal (wavelength λ1) is reflected by this filter 8 and propagates inside the condensing condenser lens 6 again. , enters the optical fiber 13 which is spaced apart from the optical fiber 1 by a distance d. Here d
is approximately proportional to the inclination angle θ and inversely proportional to the product of the refractive index of the Ronde lens and the refractive index distribution constant of the Ronde lens. Then, it propagates within this optical fiber 13 as indicated by an arrow 15',
The optical signal receiving section 3 receives the signal. The optical signal (wavelength λ1) from the optical signal transmitter 4 propagates within the optical fiber 14 as indicated by an arrow 16, passes through a focusing rod lens 6', and enters an interference film filter 8'. Since this interference film filter 8' is also formed at a desired inclination angle θ with respect to the glass block 7', the above-mentioned incident light signal (wavelength λ1) is transmitted to this filter 8.
', propagates again through the converging rod lens 6', and enters the optical fiber 1', which is spaced apart from the optical fiber 14 by a distance d'. The signal then propagates within this optical fiber 1' as indicated by an arrow 16' and is sent to the next optical terminal station. In this normal state, the semiconductor light emitting cord 10. The light receiving element 11 may also be kept in operation, that is, the optical signal of the semiconductor light emitting element 10 with one emission wavelength of λ2 is converted into parallel light by the ball lens 9, and then the light receiving element 11 is converted into parallel light by the interference film filter 8, glass block 7, and focusing rod lens. 6, the light is focused into the optical fiber 1, and propagates within the optical fiber 1 as shown by an arrow 20. Conversely, the optical signal of wavelength λ2 propagating in the optical fiber 1' as shown by the arrow 21 is transmitted through the focusing Rondo lens 6' and the interference film filter 8'.
, enters the ball lens 9' through the glass block 7',
The light is focused by the ball lens 9' and received by the light receiving element 11.

Wavelengths λ4.
Optical signals of λ2 can be transmitted bidirectionally.

Next, we will discuss the bypass function. In FIG. 2, the glass block 7.7' is rotated 180" in the direction of arrow 12. The configuration shown in FIG. signal(
The wavelength λ, ) passes through the focusing rod lens 6 and enters the interference film filter 8 . The light is then reflected by this filter 8, passes through the rod lens 6 again, and is focused into the optical fiber 2 which is spaced apart from the optical fiber 1 by a distance d'.

It propagates within the optical fiber 2 as indicated by an arrow 18. The light then passes through a focusing rod lens 6' and a glass block 7' and enters an interference film filter 8'.

It is reflected by this filter 8', passes through the glass block 7' and the focusing rod lens 6' again, and is connected to the optical fiber 2.
The light is focused into an optical fiber 1' spaced apart by a distance d from
The light propagates within the optical fiber 1' as indicated by arrow 19, and a bypass function is achieved.

Next, the loopback function will be explained using Fig. 3(b).0For example, if the optical fiber 1' is disconnected, the optical signal from the optical signal transmitter 4 cannot be sent from the terminal station 5 to 5'. In that case, an optical signal of wavelength λ2 is sent from the semiconductor light emitting device 10 into the optical fiber 1 and transmitted to the terminal station 5' through the optical fiber 1.1' shown in FIG. Conversely, if optical fiber 1 is disconnected, the optical signal is transmitted from terminal station 5 to terminal station 5 by transmitting an optical signal with wavelength λ3 from terminal station 5'' through optical fibers 1'', 1'', 1', and receiving the light. The element 11 receives the light.

As described above, in the present invention, the bypass function and the loopback function can be realized with a simple configuration without using an optical switch. Further, bidirectional transmission can also be performed using two optical signals with different wavelengths.

The invention is not limited to the above embodiments. A spherical lens may be used instead of the focusing Rondo lenses 6, 6'. The two rod lenses 6.6' may also be in close contact and arranged in an array, the glass blocks 7.7'
may be a rod-shaped or trapezoidal glass block like the focusing Rondo lenses 6, 6'. The total length including the glass block 7 (7') and the focusing rod lens 6 (6') is set to 1/4 pitch, or slightly shorter than that. In addition to the direction of the arrow 12, the glass block 7.7' may be rotated 180'' in the radial direction of the focusing Rondo lenses 6, 6' as shown by the arrows 40 and 40' to provide a bypass function ( ).

〔Effect of the invention〕

The present invention makes it possible to obtain a new optical module and optical terminal station for a loop network system that can realize a bypass function and a loopback function with a simple configuration. Therefore, an economical system can be realized. In addition, since two-wavelength bidirectional transmission can be performed even in normal conditions, larger-capacity information transmission can be realized.

Furthermore, since the optical terminal station of the present invention has a symmetrical configuration, 1
It is easy to make and is small in size.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional loop-shaped optical network system with a bypass function, FIGS. 2 and 3 are examples of optical modules and optical terminal stations used in the loop-shaped network system of the present invention, and FIG. The figure is a characteristic diagram of an interference film filter used in the optical terminal station of the present invention. 1.1', 1', 1"', 13.14... Optical fiber. 2... Optical fiber transmission line for bypass, 3... Optical signal receiving section, 4... Optical signal transmitting section, 5 t 5',
5 #, 5r*1... Optical terminal station, 6, 6'... Focusing rod lens, 7°7'... Glass block, 8
, 8'... interference film filter, 9.9'... lens,
1o... Semiconductor light emitting element, 11... Semiconductor light receiving element, 12, 40, 40'... Arrow indicating rotation direction, 15
,15', 16,16'. 17. 18, 19, 20, 21... Optical signal propagation method Figure 3 (b) Figure 4 (b) 'JL Husband

Claims (1)

[Claims] 1. A function for propagating an optical signal with a wavelength λ_2 to a transmission optical fiber B, and a function for changing the angle of the optical signal having a wavelength λ_1 propagated through the transmission optical fiber B to the left or right. An optical module having a function of switching and propagating the transmission optical fiber A to the receiving optical fiber A and the bypass optical fiber C arranged on the left and right sides of the transmission optical fiber B. 2. A function of receiving an optical signal of wavelength λ_2 propagated through the transmission optical fiber E with a light receiving element, and the transmission optical fiber E
A function to propagate the optical signal of wavelength λ_1, which has been propagated through the transmission optical fiber F juxtaposed on the left side, to the transmission optical fiber E by an angle switching displacement function, and a bypass juxtaposed on the right side of the transmission optical fiber E. An optical module having a function of propagating an optical signal of wavelength λ_1 that has been propagated through the transmission optical fiber D to the transmission optical fiber E using the angle switching displacement function. 3. A function to propagate an optical signal of wavelength λ_2 to transmission optical fiber B, and a function to change the angle of the optical signal of wavelength λ_1 that has propagated through the transmission optical fiber B to the left or right. An optical module having the function of switching and propagating the optical fiber A for reception and the optical fiber C for bypass arranged side by side on the left and right side of and a function of propagating the optical signal of wavelength λ_1 that has been propagated through the transmission optical fiber F arranged on the left side of the transmission optical fiber E to the transmission optical fiber E by an angle switching displacement function.
an optical module having a function of propagating an optical signal of wavelength λ_1, which has been propagated through a bypass optical fiber D juxtaposed to the right side of the transmission optical fiber E, to the transmission optical fiber E using the angle switching displacement function; , an optical signal receiving section is attached to the other end of the optical fiber A, an optical signal transmitting section is attached to the other end of the optical fiber F, the other end of the optical fiber C and the other end of the optical fiber D are connected, and the transmission optical fiber B is attached. , E is capable of bidirectionally transmitting optical signals of two different wavelengths, and has bypass and loopback functions.