JPH049823A - Optical crossbar switch - Google Patents

Abstract

PURPOSE:To obtain the switch which can be increased in scale with low loss by crossing row optical waveguides and column optical waveguides in three dimensions. CONSTITUTION:The row optical waveguides 1 (Xi: i=1 - 4) and wavelength demultiplexing deflectors 2 (Aij: i=1 - 4, j=1 - 4) are arranged on the top surface of a substrate 3. A wavelength demultiplexing deflector 2Aij demultiplexes a light signal with wavelength lambdaj and deflects it downward at right angles to the substrate 3. The column optical waveguides 4 (Yj: j=1 - 4) are arranged on a substrate 5 arranged in parallel to the substrate 3 and column optical waveguides 4Yj are provided with couplers 6 (Cj: j=1 - 4) which couples the light signal from the wavelength demultiplexing deflector 2Aij with a column optical waveguide 4Yj. Namely, the row optical waveguides 1 and column optical waveguides 4 cross each other in three dimensions, so there is no intersection present. Consequently, excessive loss at an intersection and performance deterioration due to the accumulation of crosstalk are eliminated and the switch is increased in scale.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical crossbar switch used in an optical exchange.

[Conventional technology]

Conventional optical crossbar switches are disclosed, for example, in Japanese Patent Application Laid-Open No. 58-15
As described in Japanese Patent No. 4821, an optical crossbar switch was constructed by intersecting a row optical waveguide and a column optical waveguide on the same plane and controlling the propagation direction of an optical signal at the intersection.

[Problem to be solved by the invention]

In the above conventional structure, there are N2 intersections in the NXN optical crossbar switch, and the optical signal must pass through a maximum of 2N-1 intersections, and the excessive loss and crosstalk experienced by the optical signal at each intersection are reduced. Due to stacking, the scale of optical crossbar switches has been limited.

An object of the present invention is to provide an optical crossbar switch that has low loss and can be scaled up.

[Means to solve the problem]

The above problem can be solved by intersecting the row optical waveguide and the photometric waveguide.

[Effect]

Since the row optical waveguide and the photometric waveguide intersect with each other, there is no intersection.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram illustrating a first embodiment of the present invention, and is an example in which the present invention is applied to a 4×4 wavelength selective optical crossbar switch. FIGS. 2 and 3 are examples of the wavelength demultiplexer and deflector portions. In FIG. 1, a row optical waveguide 1 (
Xi: i = 1 to 4) and wavelength demultiplexing deflector 2 (Ai,:
i: 1-4. , j=1 to 4) were arranged on the upper surface of the substrate 3. A□ of the wavelength demultiplexing deflector 2 demultiplexes the optical signal of wavelength λJ and deflects it perpendicularly to the substrate 3 and downward. The photometric waveguide 4 (YJ: j=1 to 4) was placed on a substrate 5 that was placed parallel to the substrate 3. The optical signal from Art of the wavelength demultiplexing deflector 2 is sent to YJ of the photometric waveguide 4.
Coupler 6 for guiding light of J (CJ: j=1 to 4)
has been established. A cylindrical lens 7 is provided on the lower surface of the substrate 3 for guiding the optical signal split and deflected on the upper surface of the substrate 3 to the Ct of the Yt coupler 6 of the photometric waveguide 4. here,
The CJ of the coupler 6 is placed on the focal line of the cylindrical lens 7.
The optical waveguides 1 in one row are arranged so that the optical signals separated and deflected at A 17 of each wavelength demultiplexing deflector 2 of XI in the row optical waveguide 1 become the guided light of YJ in the photometric waveguide 4. A wavelength demultiplexing deflector 2, a cylindrical lens 7, a coupler 6, and a photometric waveguide 4 are arranged. Here, between the cylindrical lens 7 and the substrate 5, there is a support 8 that is transparent to optical signals.
Assume that there is.

In FIGS. 2 and 3, the wavelength demultiplexer 9 is a distributed Bragg reflection type directional coupler in which a grating 12 is provided between an optical waveguide 10 and an optical waveguide 11 that are spaced apart from each other. In order to demultiplex an optical signal with a wavelength λ, the wave number of the grating 12 may be made equal to the wave number of the light with a wavelength λ in the optical waveguide. The optical signal demultiplexed by the wavelength demultiplexer 9 is transferred to the blaze grating 13 in FIG.
The beam is deflected in a direction perpendicular to the substrate 3 by a deflector 14 using a . Here, instead of the deflector 14, a mirror 15 may be used as shown in FIG.

Further, a second embodiment is shown in FIG. 4 in which the cylindrical lens 7 in FIG. 1 is replaced with a hologram 16 having a similar function.

Next, the operation of the embodiment will be explained. Here, the row optical waveguide 1
is an input-side optical waveguide, and the photometric waveguide 4 is an output-side optical waveguide. Assume that a laser whose wavelength is tunable from λ to λ is connected to each channel of the optical waveguide 1.For example, in order to realize the connection between input channel 1 and output channel 2, the input channel The wavelength of the incident light to 1 may be selected to be λ2.The optical signals split and deflected from each row of input optical waveguides are combined by a cylindrical lens 7 for each channel of the output rows of optical waveguides to be connected. be done.

Furthermore, if the wavelength selective optical crossbar switch described above is constructed from an amorphous dielectric material, such as a glass material, it is possible to construct an optical crossbar switch with low loss and whose main body is entirely passive. This eliminates the need for control at intersections, and allows optical signals to be exchanged simply by controlling the wavelength of the incident light.

Alternatively, if the wavelength demultiplexer part of the wavelength selective optical crossbar switch mentioned above is made of a material whose refractive index or absorption rate can be changed by applying an external voltage, current, light, or ultrasonic wave, the wavelength demultiplexer section can be demultiplexed. The wavelength of the waves can be controlled externally, making it possible to realize multiple different optical connection patterns with a single optical crossbar switch.

Although the embodiment has been described using a wavelength selective 4×4 optical crossbar switch as an example, the present invention is also generally applicable to an optical crossbar switch on the scale of NXM.

〔Effect of the invention〕

According to the present invention, performance deterioration due to excessive loss and crosstalk accumulation at intersections does not occur, so
It becomes possible to increase the scale of optical crossbar switches.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an optical crossbar switch showing a first embodiment of the present invention, Fig. 2 is a diagram showing a first embodiment of a wavelength demultiplexer and a deflector, and Fig. 3 is a diagram showing a wavelength demultiplexer and a deflector. FIG. 4 is a configuration diagram of an optical crossbar switch showing a second embodiment of the present invention. 1... Row optical waveguide, 2... Wavelength demultiplexing deflector, 3...
・Substrate, 4... Photometric waveguide, 5... Substrate, 6...
Coupler, 7... Cylindrical lens, 8... Support, 9... Wavelength demultiplexer, 10... Optical waveguide, 11.
...Optical waveguide, 12...Grating, 13...
Blaze grating, Z 2 RO 1 ROY 3 Figure/f

Claims (1)

[Claims] 1. An optical crossbar switch having optical coupling between an optical waveguide consisting of a plurality of rows and an optical waveguide consisting of a plurality of columns, characterized in that the row optical waveguide and the column optical waveguide are crossed three-dimensionally. Optical crossbar switch. 2. The optical crossbar switch according to claim 1, which has a structure in which the row optical waveguide and the column optical waveguide are optically coupled using at least one of a lens, a grating, a hologram, and a mirror. 3. The optical crossbar switch according to claim 1, wherein all the constituent parts are formed using an amorphous dielectric material. 4. In the optical crossbar switch according to claim 1, at least the optical signal branching portion from each row optical waveguide to each column optical waveguide is adjusted to have a refractive index or absorption coefficient by applying a voltage, current, light, or ultrasonic wave. 1. An optical crossbar switch, characterized in that it is made of a material that changes in temperature, and is provided with means for applying voltage, current, light, or ultrasonic waves to its optical signal branching portion. 5. The optical crossbar switch according to claim 1, wherein the optical signal branching portion from each row optical waveguide to each column optical waveguide is constituted by an optical circuit having wavelength selectivity. . 6. An optical crossbar switch characterized in that the optical circuit of the optical signal branching portion having wavelength selectivity as set forth in claim 5 is comprised of a distributed Bragg reflection type directional coupler having a grating in the coupling portion. 7. In the optical crossbar switch according to claim 5, the optical crossbar switch main body is composed of passive elements,
An optical crossbar switch characterized in that the optical crossbar switch is controlled by the wavelength of an optical signal input to the optical crossbar switch. 8. The optical crossbar switch according to claim 4 or 5, characterized in that the wavelength of the light branched at the optical signal branching point from the row optical waveguide to the column optical waveguide is externally controlled. crossbar switch.