JPS60233605A - Demultiplexer/multiplexer for and multiplexing optical wave - Google Patents

Abstract

PURPOSE:To enable manufacture of a small sized demultiplexer and multiplexer permitting easy assembly and adjustment by using optical waveguides formed with a pattern for a high refractive index part in a low refractive index substrate and providing a wavelength selecting part to the end face thereof. CONSTITUTION:The demultiplexer and multiplexer are constituted of an optical fiber 10 for conducting light signals for input and output, the low refractive index plane substrate 20 formed internally with the three-dimensional optical waveguide 70 of the high refractive index part for conducting the light signal to be demultiplexed or multiplexed and the wavelength selecting part WRC formed at the end face of the substrate 20. The WRC is constituted of interference film filters 31, 32, 33, 34 having specified wavelength selective transmittability, the substrates 81, 82 formed with the optical waveguides 71, 72, etc. which are connected respectively thereto and conduct the light signals, optical fibers 11, 12, 13, 14, etc. to be connected thereto, etc. The incident light is transmitted or reflected by the respective filters but the transmitted or reflected light are outputted respectively via separate optical waveguides and optical fibers according to such constitution. The need for lenses for condensing is thus eliminated, constituting parts are decreased, the size is reduced and the assembly and adjustment are made easy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical multiplexing/demultiplexing multiplexer that demultiplexes optical signals multiplexed at different wavelengths or multiplexes optical signals of different wavelengths.

In order to realize optical wavelength division multiplexing communication, optical demultiplexers and multiplexers are required. Conventionally, these types of demultiplexers and multiplexers have been used to separate optical wavelengths using prisms, diffraction gratings, or interference film filters. It consisted of a selection element, a lens, and a glass block connecting them.

An example of the structure of a conventional optical wavelength demultiplexer/multiplexer will be explained with reference to FIG. The wavelength λ1 incident from the optical fiber 10. λ2.
The lights of λS and λ4 are focused by a lens 41 and enter the glass block 22. The light entering the glass block 22 travels straight, passes through the glass block 21, and enters the interference film filter 31. As shown in FIG. 2, the interference film filter 31 transmits only the optical signal of wavelength λl, so that the interference film filter 31 transmits only the optical signal of wavelength λl, λ2°λ3, . Among the optical signals of λ4, only the optical signals with a wavelength of 2 ri pass through the interference film filter 31, go straight through the glass block 23, are focused by the lens 42, and are sent to the optical fiber 11 as λM-F circle-''8 wavelengths λ The light of λ1.λ□ is.

It is totally reflected by the interference film filter 31, passes through the glass block 21, and enters the interference film filter 32. Since the interference film filter 32 transmits only the optical signal of wavelength λ2 as shown in FIG. 4, the interference film filter 32 transmits only the optical signal of wavelength λ2. Among the optical signals of λ3° and λ4, only the optical signal of wavelength λ2 passes through the interference film filter 32, travels straight through the glass block 24, is focused by the lens 43, and enters the optical fiber 12. Also, the wavelength λ3. The light of wavelength λ4 is reflected by the interference film filter 32, and the light of wavelength λ! ,λ
Similarly to the optical signal of No. 2, the wavelength λ3. Alternatively, at the filter 33, 34 that transmits the light of wavelength λ4, it is separated from other optical signals, and enters the optical fiber 13, 14 through the glass blocks 25, 26 and lenses 44, 45, respectively.

As described above, the wavelengths λl, λ2. λ3. The optical signals optically multiplexed by λ4 are demultiplexed and sent to optical fibers 11.
It is incident on 12, 13 and 14.

When the configuration shown in FIG. 1 is used as a multiplexer, the direction of light incidence is reversed. That is, an optical signal of wavelength λ4 is transmitted through optical fiber 1.
It enters from 4. Wavelength λ incident from optical fiber 14
The optical signal No. 4 is condensed by a lens 45, passes through a glass block 26, and enters an interference film filter 34. As shown in FIG. 2, the interference film filter 34 transmits the optical signal with the wavelength λ4, so the optical signal with the wavelength λ4 passes through the interference film filter 34, goes straight through the glass block 21, and passes through the interference film filter 3.
3. The interference film filter 33 transmits the optical signal with the wavelength λ3, but totally reflects the optical signals with other wavelengths, so the optical signal with the wavelength λ4 that has passed through the glass block 21 is reflected. On the other hand, the optical signal of wavelength λ3 incident from the optical fiber 13 is focused by the lens 44 and is focused by the glass block 25. It passes through the interference film filter 33 and is combined with an optical signal of wavelength λ4 that is totally reflected by the interference film filter 33. Wavelength λ2. λl
The optical signals K are input from the optical fibers 12 and 11, respectively, and are multiplexed in the same manner as described above. In this way, the wavelength λ1. λ2. λ3. The combined optical signal of λ4 passes straight through the glass blocks 21 and 22, and passes through the lens 41.
The light is focused at wavelength λ1. from optical fiber 1o. λ2. λ3
A multiplexed optical signal of .lambda.4 is obtained.

As described above, in conventional demultiplexing/multiplexing devices, since a glass block is used as an optical path, the light is diffused, and the optical signal from or to the optical fiber needs to be focused through a lens. Furthermore, since the optical fiber, lens, and demultiplexer/multiplexer main body are individually constructed, there are a large number of component parts, making it difficult to assemble and adjust, and also having disadvantages in that it is less economical and mass-producible.

The present invention uses an optical waveguide in which a pattern of high refractive index portions is formed in a low refractive index substrate in the optical path of an optical signal, and provides a wavelength selection portion formed on the end face of the optical waveguide, thereby improving the optical path of the optical signal. It is an object of the present invention to provide an optical demultiplexer/multiplexer which solves the drawbacks, is easy to assemble and adjust, and can be constructed in a small size.

Another object of the present invention is to form an optical fiber or a light emitting element and a waveguide, or a waveguide and an optical fiber, or a light receiving It is an object of the present invention to provide an optical demultiplexer/multiplexer that increases the coupling efficiency of light between elements, reduces the number of components, and reduces insertion loss.

That is, the optical demultiplexer/multiplexer according to the present invention forms a three-dimensional waveguide by creating a high refractive index portion in a low refractive index flat substrate,
The planar substrate is cut along the plane that includes the waveguide, and a wavelength selective element is provided on this cut plane. This eliminates the diffusion of light between the wavelength selective elements and prevents the formation of lenses, etc. A condensing element can be made unnecessary.

In this case, by performing demultiplexing and multiplexing multiple times on one planar substrate, the number of components can be reduced, and a demultiplexer/multiplexer that is small and easy to assemble and adjust can be obtained. Also,
By forming a structure that functions as a lens together with an optical waveguide on a single planar substrate, it is possible to effectively demultiplex and multiplex light with a large radiation angle from light emitting elements, etc., without increasing the number of components. In this respect, it is also possible to obtain a demultiplexer/multiplexer that is small and has low insertion loss.

Embodiments of the present invention will be described below with reference to one drawing. - FIG. 3 is a schematic diagram of a multiplexer/demultiplexer according to an embodiment of the present invention. In this embodiment, input and output optical signals are guided through an optical fiber 1.
0, a low refractive index flat substrate 20 connected to the optical fiber 10 and having a high refractive index three-dimensional optical waveguide 70 formed therein for guiding an optical signal to be demultiplexed or a combined optical signal;
Interference film filters 31, 32, 3 formed on the end face of the substrate 20 and having wavelength selective transmittance as shown in FIG.
3.

34, substrates 81, 82 formed with optical waveguides 71, 72, 73, 74 that are connected to these interference film filters and guide the demultiplexed optical signals or the combined optical signals, and The optical fibers 11, 12, 13, and 14 are connected to the substrates 81, 82 so as to guide the optical fibers.

Next, the operation of the demultiplexer/multiplexer of this embodiment will be explained separately for demultiplexing and multiplexing. First, when the configuration shown in FIG. 3 is operated as a demultiplexer, the wavelengths to be demultiplexed λhλ2. λ3. λ
An optical signal obtained by multiplexing the four lights is made to enter the optical waveguide 70 formed on the substrate 20 from the optical fiber 10. The optical signal entering the optical waveguide 70 travels along the line groove wavepath (without being diffused by the action of the optical waveguide 70) and enters the interference film filter 31.The interference film filter 31 is shown in FIG. Since it is transparent only to the optical signal with the wavelength λ□, only the optical signal with the wavelength λ1 is transmitted, enters the optical waveguide 71 formed in the substrate 81, and proceeds along the waveguide 71. , is outputted through the optical fiber 11. On the other hand, the light wavelength λ2.λ is totally reflected without passing through the interference film filter 31.
3. The optical signal of λ4 is further transmitted to the optical waveguide 7o in the substrate 20.
, and enters the interference film filter 32. Here, like the optical signal of wavelength λl, only the optical signal of wavelength λ2 passes through the interference film filter 32 and is outputted via the optical waveguide 72 and the optical fiber 12. Wavelength λ3. The optical signal of wavelength λ4 is totally reflected by the interference film filter 32, and the optical signal of wavelength λ3. The optical signals of λ4 are also demultiplexed, input into optical fibers 13 and 14, and outputted through the fibers.

Next, when using the configuration shown in FIG. 3 as a multiplexer, the wavelength λ1 to be multiplexed. λ2. λ3. Optical signals of λ4 are input from optical fibers 11, 12, 13, and 14, respectively. Wavelength λhλ2. λ3. The optical signals of λ4 are incident on optical waveguides 71, 72, 73, and 74 connected to the fibers, respectively, and guided by the optical waveguides to interference film filters 31, 32, and 3.
3.34.

The interference film filters 31, 32, 33.34 have wavelengths λl, λ2, . λ3. Since it is transparent to the optical signal of λ4, the incident optical signal is transmitted and enters the optical waveguide 70 in the substrate 20. The incident optical signal with a wavelength of λ□ enters the optical fiber IOK as it is, and becomes λ2゜λ3. Optical signals with a wavelength of λ4 are transmitted from the optical waveguide 70 to the interference film filters 31, respectively.
, 32.33, but these interference film filters have wavelengths λ2. λ3. Since the light of λ4 has no transparency, it is totally reflected here and roughly travels through the optical waveguide 70. As described above, the wavelength λ1 transmitted through the interference film filter 31
with optical signals.

Proceeding through the optical waveguide 70, interference film filters 31 and 32
．． 33, the wavelength λ2. λ3. The optical signals of λ4 are multiplexed and output from the optical fiber 10.

In the above embodiment, since the optical signals to be demultiplexed and multiplexed are guided by the optical waveguide, there is no need for a condensing lens between the optical fiber and the demultiplexer and multiplexer. Further, the optical waveguide 71.73 and the leading waveguide 72.74 are connected to the substrate 81.82 as shown in FIG.
Furthermore, since the interference film filter can be formed directly on the end surface of the substrate 20, the number of components can be reduced compared to the configuration shown in FIG. Therefore, the demultiplexer/multiplexer is miniaturized, and furthermore, assembly and adjustment are facilitated.

FIG. 4 is a schematic diagram showing another embodiment of the present invention. This embodiment includes an optical fiber 10 for guiding input/output light, an optical waveguide 70 connected to the optical fiber 1o and formed in a substrate 2o for guiding optical signals to be demultiplexed and multiplexed; Waveguide lens 5 incorporated in the optical waveguide end of the substrate 2o
1, 52, 53° 54, and interference film filters 31, 32, 33, and 34 formed at the ends of the substrate and having wavelength selective transmittance as shown in FIG. 2, for example, and in contact with these interference film filters. A light-receiving element 6 that is arranged and converts an optical signal into an electrical signal or a light-emitting element 6 that converts an electrical signal into an optical signal.
1, 62, 63, and 64.

Next, the operation of the embodiment shown in FIG. 4 will be explained. In the configuration shown in FIG. 4, the elements 61, 62, 63, and 64 are used as light receiving elements to operate as an optical wavelength multiplexing receiver, and the elements 61, 62, 63, and 64 are used as light emitting elements to operate as an optical wavelength multiplexing transmitter. First, as an optical wavelength multiplex receiver, wavelengths λ], λ2 . λ3. A multiplexed optical signal of λ4 is made to enter an optical waveguide 70 formed in a substrate 20 from an optical fiber 10. The optical waveguide 70 guides the incident optical signal to the waveguide lens 51 . The light incident on the waveguide lens 51 is focused by the waveguide lens 51 and is incident on the interference film filter 31.

As shown in FIG. 2, the interference film filter 31 is transparent only to the optical signal with the wavelength λl, so only the optical signal with the wavelength λ1 is transmitted and enters the light receiving element 61, where electricity is extracted from the optical signal. converted into a signal. On the other hand, the wavelength λ2. λ3. λ4
The optical signal is totally reflected by the interference film filter 31, focused by the waveguide lens 51, and travels through the optical waveguide 70 again to the waveguide lens 52. Wavelengths λ2°λ3. focused by the waveguide lens 52. The optical signal of λ4 is passed through an interference film filter 32.
1C is incident. Here, only the optical signal of wavelength λ2 passes through the interference film filter 32, similar to the optical signal of wavelength λ1 described above.

The light enters the light receiving element 62 and is converted from an optical signal to an electrical signal. Hereinafter, wavelengths λ3, . λ
The optical signals of No. 4 are also demultiplexed by interference film filters 33 and 34, and enter respective light receiving elements 63 and 64.

The optical signal is converted into an electrical signal.

Next, when the configuration shown in FIG. 4 is used as an optical wavelength multiplex transmitter, the light emitting elements 61, 62, 63, and 64 transmit electric signals at wavelengths λ1, . λ2. λ3. It is converted into an optical signal of λ4 and input to interference film filters 31, 32, 33°34. Interference film filters 31 , 32 .

33.34 are the wavelengths λ□, λ2. λ3. Since it is transparent to the optical signal of λ4, the incident optical signal is transmitted and enters the waveguide lenses 51, 52, and 53° 54, respectively. Generally, the radiation angle of light from a light emitting element is large, but 2
In the present invention, waveguide lenses 51, 52, 53 .
54 is provided, and the optical signal is focused by this waveguide lens and made to enter the optical waveguide 70 with high efficiency. incident wavelength λ
2. λ8. The optical signal of λ4 travels along the optical waveguide 70, is focused by the waveguide lenses 51, 52.53, and enters the interference film filters 31, 32, 33, but the interference film filters 31, 32, 33 Each wavelength λ1. λ2λ3
Since it has no transparency for other optical signals, it is totally reflected and transmitted through the interference film filters 31, 32, and 33, respectively.
, λ2. Combined with the optical signal of λ3, the waveguide lens 51,
52 and 53 and enters the optical waveguide 70Vc. The 4° optical signal combined as described above is sent to the waveguide 7.
In the embodiment shown in FIG. 4 described above, in which the light is input from 0 to the optical fiber 10, a lens is formed in the optical waveguide to demultiplex the light, receive the light directly to the multiplexer, attach a light emitting element 9, and transmit the light. Since it can be used as a wavelength multiplex receiver and transmitter, it is possible to convert a drowsiness signal to an optical wavelength multiplexed signal, or from an optical wavelength multiplexed signal to an electrical signal, with fewer components.
This can be achieved with a small device.

As explained above, the present invention uses an optical waveguide in the optical path in the demultiplexer and multiplexer, and also provides a waveguide lens in the optical waveguide that takes advantage of the difference in refractive index between the optical waveguide and the substrate. By using 95 demultiplexers, you can easily prevent light divergence in the multiplexer, eliminate the need for an external lens, and use the demultiplexer and multiplexer body [direct optical fiber,
A light receiving element and a light emitting element can be attached. As a result, the number of components is small and the structure is simple, resulting in a demultiplexer and multiplexer that has high optical coupling efficiency, is compact overall, and is easy to assemble and adjust.

[Brief explanation of the drawing]

Figure 1 is a schematic plan view of a conventional optical multiplexer/demultiplexer, Figure 2 is a diagram showing the wavelength transmission characteristics of an interference film filter that acts as a wavelength selection mechanism, and Figure 3 is an embodiment of the present invention. FIG. 4 is a schematic plan view showing another embodiment of the present invention. 10.11, 12, 13.14... optical fiber, 20
．． 81.82 ...low refractive index flat substrate, 31.32,
33.34...Interference film filter, 51.52,53.
54... Waveguide lens, 61.62, 63.64...
- Light receiving element or light emitting element, 70.71, 72, 73.
74...High refractive index optical waveguide. Agent Patent Attorney Rikichi Someyo No. 1 Figure 2 Torunaga Figure 3 Figure 4 Procedural Amendment (Female) Date of 1939 and March 30th Patent Participant ゛r Mutsurugaku-dono Incident Display Spit. 1937, Sex Request No. 7062θ, EIFI's synopsis, Oa 1, Imasaka Shaba Akuta, 3, Relationship with the case of the person making the amendments, Taketsuri°de I'K, Mei Kojinuki - Agency Letters (nup, AnP Le L)

Claims (3)

[Claims] (1) A three-dimensional optical waveguide with a high refractive index portion is provided on a low refractive index flat substrate, and at the intersection of the optical waveguides, only the optical signal of the required wavelength is transmitted through the end face of the flat substrate, and the other optical signals are transmitted. A demultiplexer/multiplexer characterized by being provided with a wavelength selection mechanism that reflects optical signals of different wavelengths. (2) A three-dimensional waveguide is provided in the same plane substrate to re-guide the light reflected by the wavelength selection mechanism, and demultiplexing and multiplexing are performed multiple times using another wavelength selection mechanism. The demultiplexing/multiplexing device according to claim 1, characterized in that: (3) A waveguide lens using a high refractive index portion is provided in a low refractive index flat substrate together with the three-dimensional waveguide. Wave combiner.