JP3271449B2 - Beam forming circuit for phased array - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phased array beam forming circuit for feeding a signal having a predetermined phase and amplitude to a plurality of radiating elements in a phased array system used in mobile communication or personal communication.

[0002]

2. Description of the Related Art In mobile communication or personal communication, etc., it is required to increase the capacity of transmission signals and to reduce the size of a portable device. For this purpose, a phased array system is being studied. In the phased array system, since power is synthesized in space, highly efficient power transmission is possible. Also,
Since a beam with high directivity can be formed, the frequency can be repeatedly used. Further, since the emission direction of the beam can be made variable, a transmission path with high flexibility against traffic fluctuation can be realized.

In order to realize such a phased array system, a beam forming circuit for feeding a signal having a predetermined phase and amplitude to a plurality of radiating elements is required. However, when this is constituted by an electric circuit, there is a problem that the circuit scale becomes enormous for a large-scale antenna for mounting on a communication satellite having hundreds of radiating elements. Therefore, there has been proposed a beam forming circuit for a phased array in which the circuit scale is significantly reduced by using an optical circuit, and the overall size and weight are reduced.

FIG. 6 shows a configuration example of a conventional beam forming circuit for a phased array using an optical circuit. In the figure,
The light source 1 outputs a signal light whose intensity is modulated by a transmission electric signal. Signal light is beamforming circuit 2 for phased array
And is distributed to N paths according to the number of radiating elements, and a predetermined phase is given to each of the N variable phase shifters 20 arranged in each path. The signal light output from each variable phase shifter of the phased array beam shaping circuit 2 is converted into an electric signal by the light receiver 3, further amplified by the amplifier 4, and supplied to the radiating element 5. The variable phase shifter 20 used here does not change the phase of the light wave, but changes the phase of the finally obtained electric signal. By giving a predetermined phase distribution with such a variable phase shifter, a beam can be formed in an arbitrary direction (radiation angle Θ).

[0005] This configuration example is for a so-called single beam, which forms one beam. Since a multi-beam forming circuit for simultaneously forming a plurality of beams can be configured by combining these, a single-beam forming circuit for a phased array will be described in this specification. FIG. 7 shows a configuration example of a conventional variable phase shifter.

The configuration example shown in FIG. 7A has L fixed delay lines 200 having different line lengths, and signal light is incident on one fixed delay line selected by the optical path selection switch 100. . The signal light having passed through the fixed delay line is output via the optical multiplexer 300. Note that the optical multiplexer 300 may use the optical path selection switch 100 in some cases.

[0007] The configuration example shown in FIG. 7B has L fixed delay lines 200 having different line lengths, and the signal light is distributed to each fixed delay line via an optical distributor 400. One of the signal lights passing through each fixed delay line is an optical path selection switch 1.
This is a configuration that is selected and output at 00. In any of the configurations, the signal light passing through the variable phase shifter can be changed in phase according to the line length of the fixed delay line selected by the optical path selection switch 100.

FIG. 8 shows a study example of a variable phase shifter using a semiconductor optical waveguide (W. Ng, et al., “GaAs Optical Ti
me-Shift Network for Steering a Dual-Band Microw
avePhased Array Antenna ", SPIE Vol.1703, pp.379-38
3, 1992). This study example corresponds to the configuration example shown in FIG. 7B, and includes a delay line 210 using a semiconductor optical waveguide forming an optical distributor 400 and a plurality of fixed delay lines 200 on a semiconductor substrate 7. , Optical path selection switch 10
The MSM detector 6 is monolithically formed as 0 and the light receiver 3. The MSM detector 6 simultaneously realizes a photoelectric conversion function as a light receiver and a switch function of selecting a predetermined optical waveguide by turning on and off a drive voltage.

By using such a semiconductor optical waveguide, there is an advantage that a plurality of fixed delay lines and a photoelectric conversion element such as a photodetector can be integrally formed. However, the semiconductor optical waveguide generally has a large propagation loss of 1 dB / cm or more, and is not suitable for a delay line having a line length difference of about the wavelength of a microwave used as a signal (about 1 to 10 cm). Further, although the semiconductor optical waveguide can reduce the bending radius, it has a large bending loss, and a loss of about 0.5 dB occurs in an S-shaped bending with a bending radius of 1.5 mm. Therefore, the semiconductor optical waveguide is not suitable for a delay line that uses many bending optical waveguides. That is, in the variable phase shifter using the semiconductor optical waveguide, the insertion loss of the average circuit becomes large, and the loss difference between the delay lines becomes large, so that it is difficult to set the delay line length difference large. Met. In addition, the optical distributor formed by the semiconductor optical waveguide has a principle of 10
Since there is a branch loss of × log L (dB), the insertion loss is further increased, and there is a problem that the setting range of the line length by the delay line is limited.

FIG. 9 shows a configuration example of a conventional variable phase shifter. This configuration example is a cascade connection of the configuration example shown in FIG. That is, a configuration in which the optical delay line selection circuit 30 composed of the optical path selection switch 100 and the fixed delay line 200 is connected in cascade in M stages, and the optical multiplexer 300 is connected to the optical delay line selection circuit 30 in the M stage. It is.

In such a configuration, L ^M different paths can be selected, and the degree of freedom in selecting the delay amount is much greater than the number of paths L × M when the same number of delay lines are formed in parallel. , Flexible beam steering is possible. However, in the configuration in which delay lines are connected in cascade as in this configuration, the average line length is longer than in the parallel configuration. Therefore, in the case of using a semiconductor optical waveguide, the propagation loss increases, and the degree of freedom in selecting the amount of delay cannot be increased so much due to the limitation of the number M of cascade connections.

FIG. 10 shows a study example for solving the problems of the configuration example of the conventional variable phase shifter (CTSullivan, et al.).
al., "Switched Time Deley Elements Based on AlGaAs /
GaAsOptical Waveguide Technology at 1.32μm for Op
tically Controlled PhasedArray Antennas ", SPIE Vo
l.1703, pp.264-271, 1992). In the present study example, only the 2 × 2 electro-optic effect switch 110 serving as an optical path selection switch is formed on the semiconductor substrate 7, and the fixed delay line 200, which is considered to cause most of the propagation loss and bending loss, is connected to the optical fiber delay switch. It is configured using the line 220. With this configuration, it is possible to reduce the difference in the propagation loss of each path.

However, the 2 × 2 electro-optic effect switch 11
Since the semiconductor optical waveguide constituting the optical fiber 0 has a smaller core diameter than the optical fiber and a mode field shape different from that of the optical fiber, a large fiber connection loss of about 5 dB per connection point occurs, and a fundamentally low loss occurs. It was difficult to realize loss. On the other hand, there is a method using a spherical lens or fiber to reduce the connection loss between the semiconductor optical waveguide and the optical fiber. In this method, the connection loss can be reduced by about 1 to 3 dB per connection point, but connection accuracy on the order of submicrons is required. There was a problem that the variation became large. Further, since the semiconductor optical waveguide has polarization dependency, it is necessary to use a polarization maintaining optical fiber as the optical fiber delay line 220, but it is necessary to connect both ends of the optical fiber as in the present study example. Furthermore, when performing the spherical lens processing, it has been difficult to make a connection while maintaining the polarization.

Further, in the configuration using the optical fiber delay line 220, it is necessary to precisely adjust the length of the fiber.
It was not suitable for anything that had to be adjusted on order. Also, from the viewpoint of manufacturing stability, a planar circuit configuration that can easily realize precise delay amount adjustment has been desired. On the other hand, a configuration using a silica-based optical waveguide capable of realizing the same propagation loss as an optical fiber has been studied.

FIG. 11 shows a study example of a variable phase shifter using a silica-based optical waveguide (W. Ng, et al., "GaAs and Silica-B").
ased Integrated Optical Time-Shift Network for Pha
sedArrays ", SPIE Vol.2155, pp.114-123, 1994. In this example, an L ₁ × L ₂ optical star coupler 410 using a silica-based optical waveguide is sandwiched on a silica-based optical waveguide substrate 8. so,
L ₁ A delay line 230 using a silica-based optical waveguide and L ₂
A delay line 231 using a plurality of quartz optical waveguides is formed, and a configuration including L ₁ light sources 1 corresponding to the delay line 230 and L ₂ light receivers 3 corresponding to the delay line 231 is provided. is there. Here, by using any one light source, one of the L ₁ delay lines 230 in the preceding stage can be selected. Further, by turning on any one of the light receivers 3, one of the L ₂ delay lines 231 at the subsequent stage can be selected. Thus, L ₁ × L ₂ delay amounts can be selected.

In this configuration, since a silica-based optical waveguide is used, the propagation loss in the delay line is small. However, an optical star coupler 41 is provided between the delay line of the preceding stage and the delay line of the subsequent stage.
Since the coupling is performed at 0, a branch loss of 10 × log L ₂ (dB) occurs in principle, and the low loss property of the optical waveguide cannot be utilized, and the number of delay lines at the subsequent stage is limited. Further, in such a configuration in which the optical path selection switch is not interposed between the delay lines, the number of stages of the conventional connection of the delay lines is limited to two stages in the present study example, and there is no expandability. Further, L ₁ light sources and L ₂ light receivers must be prepared for the variable phase shifter in one optical path, which has been a factor of increasing the circuit scale.

[0017]

As described above, in a real-time delay type phased array beam forming circuit requiring a line length difference of about the wavelength of a microwave, a fixed delay line of a variable phase shifter is used. The configuration using the semiconductor optical waveguide has a problem that a large insertion loss is unavoidable and a large loss difference occurs between different paths. Therefore, the delay amount difference and the freedom of selecting the delay line are limited,
Flexible beam steering could not be realized.

Further, although the LiNbO ₃ optical waveguide has a smaller propagation loss than the semiconductor optical waveguide, it has a large bending loss because it is an optically anisotropic crystal, so that it is not possible to form a delay line that requires bending on a substrate. It was difficult. Also, LiNb
Since O ₃ has a greater polarization dependency than a semiconductor, its manufacturability was poor as in the case of using an optical fiber delay line.

On the other hand, in a configuration using a silica-based optical waveguide,
The quartz optical waveguide functions as a passive circuit, and there is no active circuit such as an optical path selection switch. Therefore, the low loss property of the optical waveguide cannot be utilized,
The circuit expandability or beam steering flexibility was limited. SUMMARY OF THE INVENTION An object of the present invention is to provide a phased array beam forming circuit that has low loss, excellent manufacturing stability, excellent environmental stability, and has a high degree of freedom in selecting a delay amount for enabling flexible beam steering. I do.

[0020]

SUMMARY OF THE INVENTION The present invention relates to a phased array beam for dividing a transmission signal light into a plurality of paths, applying a predetermined amplitude and phase to the signal light of each path, and supplying the signal light to a plurality of radiating elements. In the shaping circuit, an optical distributor using a silica-based optical waveguide that divides the transmission signal light into a plurality of paths, and a plurality of variable phase shifters connected in parallel at the subsequent stage, the variable phase shifter, One or more optical delay line selection circuits, which connect an optical path selection switch using a thermo-optic effect optical switch and a delay line using a plurality of silica-based optical waveguides having different line lengths, are connected in cascade. An optical path selection switch using a thermo-optic effect optical switch or an optical multiplexer is connected to the optical delay line selection circuit (claim 1).

The variable phase shifter of the beam shaping circuit for a phased array according to the present invention comprises an optical path selection switch using an optical gate switch and a plurality of quartz optical waveguides connected to the subsequent stage and having different line lengths. This is a configuration including a delay line used and an optical multiplexer using a silica-based optical waveguide connected to the subsequent stage. Further, the beam forming circuit for a phased array according to the present invention includes an optical distributor using a silica-based optical waveguide that divides a transmission signal light into a plurality of paths, and a plurality of quartz with different line lengths connected in parallel in a subsequent stage. A plurality of fixed phase distribution providing circuits each of which sets a predetermined phase distribution, and an optical path selection for inputting transmission signal light to one of the plurality of fixed phase distribution providing circuits. The switch includes a switch and an optical multiplexing unit using a silica-based optical waveguide that multiplexes delay line outputs corresponding to the plurality of fixed phase distribution providing circuits and supplies the multiplexed outputs to corresponding radiating elements. ).

[0022]

The beam shaping circuit for a phased array according to the present invention divides a transmission signal light into a plurality of paths, applies a predetermined amplitude and phase to the signal light on each path, and supplies the signal light to a plurality of radiating elements. It is almost the same as technology. The present invention is characterized in that a quartz optical waveguide is used and a flexible delay amount switching function is provided.

The silica-based optical waveguide has a propagation loss similar to that of an optical fiber and is extremely low, a bending loss and a crossing loss are small, and a circuit can be formed on a large-area substrate.
It has features such as a small connection loss with an optical fiber and excellent environmental stability against temperature, humidity and the like. Table 1 shows a general comparison between a silica-based optical waveguide and a semiconductor optical waveguide.

[0024]

[Table 1] By using such a silica-based optical waveguide, a relatively long circuit having a wavelength of about the microwave can be easily formed, and the difference in loss when propagating through paths having different line lengths can be extremely reduced. it can. Further, since the bending loss of the silica-based optical waveguide is extremely small, a group of delay lines having a large line length difference can be collectively formed on the same substrate. Further, since a large-area substrate can be used, it can be formed on the same substrate even if the circuit scale becomes large to some extent. Furthermore, the silica-based optical waveguide has good connectivity with the optical fiber, and can reduce connection loss with the optical fiber when inputting / outputting to / from the optical waveguide. In addition, since environmental stability with respect to temperature, humidity, and the like is excellent, it is possible to avoid a large-scale peripheral device such as a temperature control device.

Further, by using a thermo-optic effect optical switch utilizing the thermo-optic effect of a quartz optical waveguide as the optical path selection switch, the optical distributor, the optical path selection switch, the delay line, and the optical multiplexer are all integrated. And can be formed on the same substrate (claim 1). Further, by using an optical gate switch using a semiconductor gate element or the like as an optical path selection switch, an optical path can be selected at high speed. As a result, high-speed steering of the beam can be performed, and the power consumption of the switch unit can be reduced (claim 2).

In the beam shaping circuit for a phased array according to the third aspect, the signal light is input from the optical path selection switch to one fixed phase distribution providing circuit, and the corresponding phase distribution is set. Here, by using the silica-based optical waveguide having a small cross loss, the signal light output from each fixed phase distribution providing circuit can be supplied to the corresponding light receiver and radiating element without any trouble.

[0027]

【Example】

(First Embodiment) FIG. 1 shows the configuration of a first embodiment of the present invention. The phased array beam shaping circuit of the present embodiment corresponds to the conventional phased array beam shaping circuit 2 shown in FIG. 6, and is characterized in that the circuit is configured using a quartz-based optical waveguide. is there.

In the figure, on a silica-based optical waveguide substrate 8,
An optical distributor 420 using a silica-based optical waveguide and N variable phase shifters 20 all formed of a silica-based optical waveguide are formed. The signal light is input to the optical splitter 420, distributed to N paths according to the number of radiating elements, and given a predetermined phase by N variable phase shifters 20 arranged in each path, respectively. Sent to the receiver. The variable phase shifter 20 of the present embodiment is an optical delay line composed of a thermo-optic effect switch 120 used as an optical path selection switch and a delay line 230 using two quartz optical waveguides having different line lengths. The configuration is such that the selection circuits 30 are connected in cascade in M stages, and a thermo-optic effect switch 310 used as an optical multiplexer is connected to the M-stage optical delay line selection circuit 30.

FIG. 2 shows the thermo-optic effect switches 120 and 31.
0 shows a configuration example. In the figure, the thermo-optic effect optical switch is configured by a Mach-Zehnder interferometer formed by two 3 dB directional couplers 121 and an arm waveguide 122 on which a heater electrode 123 is loaded on a silica-based optical waveguide. By turning on / off the power supply 124 connected to the heater electrode 123, the power supply 124 functions as an optical path selection switch or an optical multiplexer.

As the silica-based optical waveguide, an embedded single-mode optical waveguide having a relative refractive index difference of 1.5% between the core and the clad is used.
A propagation loss of 0.1 dB / cm or less, a coupling loss with an optical fiber of 1 dB, and a bending radius of 2 mm, which are comparable to those of an optical fiber, are realized. Such an optical waveguide can be easily manufactured on a silicon substrate by flame deposition and reactive ion etching. The heater electrode 123 is formed by depositing a chromium thin film on the upper clad in the final step.

In the beam forming circuit for a phased array of this configuration, when N = 4 and M = 4, 2 ^M = 16 kinds of path selections are possible. In addition, the width in the beam direction is 2.5G
Beam scanning is possible in a large range of -50 to +50 degrees with respect to a microwave signal of Hz. In addition, the total insertion loss of the circuit is suppressed to 9 dB or less.
dB and fiber splice loss of 2 dB are included.

As described above, by using the silica-based optical waveguide, the width in the beam direction is large, the operation of the delay amount can be finely performed, and the beam steering can be performed flexibly by setting the phase of each path. Further, since a large-area circuit can be formed with low loss, it is possible to form all of the beam forming circuits for a phased array on the same substrate. Such good characteristics are due to the use of a silica-based optical waveguide having excellent low-loss characteristics and the use of an optical path selection switch (thermo-optic effect optical switch) formed of the silica-based optical waveguide.
Conventionally, materials having an electro-optical effect, such as LiNbO ₃ and semiconductors, have been widely used as optical path selection switches. In the present embodiment, a thermo-optical effect optical switch utilizing the thermo-optical effect of quartz glass is used. Is used. As a result, the optical path selection switch, the delay line, the optical multiplexer, and the optical distributor can all be formed collectively on the same substrate, and the connection loss can be reduced and a precise delay line length can be easily realized. .

The thermo-optical effect switch using the quartz optical waveguide has a disadvantage that the operation speed is slower (about 1 msec) than the electro-optical effect switch such as a semiconductor. However, for applications such as changing the frequency allocation in response to long-term traffic fluctuations, the switching time of the beam direction does not matter so much, and the operation speed of the thermo-optic effect optical switch is sufficient. Can be handled.

(Second Embodiment) FIG. 3 shows the configuration of a second embodiment of the present invention. The configuration of the variable phase shifter 20 is different from that of the first embodiment. In this embodiment, an optical gate switch 130 using a semiconductor gate element as an optical path selection switch, and a delay line 230 using a silica-based optical waveguide having a different line length are used.
And an optical multiplexer 320 using a silica-based optical waveguide.

FIG. 4 shows a configuration example of the optical gate switch 130 when the number of delay lines is four. Optical gate switch 130
Is composed of an optical four-branching circuit 131 and a semiconductor gate array 132. Such a configuration uses a hybrid optical integration technique on a silica-based optical waveguide, and thereby, the delay line 230 and the optical multiplexer 3 using the silica-based optical waveguide are used.
20 can be formed on the same substrate (Y. Yamada,
et al., "Hybrid-Integrated 4 × 4 Optical Gate Matri
x Switch Using Silica-Based OpticalWaveguides and
LD Array Chips ", J. Lightwave Technol., Vol. 10, pp. 3
83-390,1992). That is, an element mounting portion may be formed at a predetermined position on the quartz optical waveguide substrate by reactive ion etching, and the semiconductor gate array 132 may be mounted and fixed. In addition, if it is a configuration using a quartz optical waveguide,
The optical gate switch 130 may be made of another material.

In such a configuration, the optical gate switch 1
Since the path can be selected by turning on / off the switch 30, a high-speed optical path selection operation can be performed, and the present invention can be applied to an application in which a beam is scanned at a high speed. Further, the thermo-optical effect light switch requires about 0.5 W of power to be consumed by one switch because it has a heater. However, in this embodiment, since the semiconductor gate element is used, the driving power is at most 0.05 W, Significant power reduction can be achieved.

In the optical gate switch 130, a branch loss occurs because light is distributed and passes through only a predetermined path, and a connection loss occurs because the gate portion is made of a different material. However, by driving with an appropriate current using a semiconductor gate element, not only connection loss can be compensated, but also gain can be obtained. Further, by controlling the drive current, it is possible to compensate for variations in connection loss of each port of the optical gate switch, and to obtain a predetermined amplitude.

(Third Embodiment) FIG. 5 shows the configuration of a third embodiment of the present invention. In the figure, an optical path selection switch 100, a fixed phase distribution providing circuit 40 for setting J kinds of phase distributions, and an optical multiplexing section 50 are formed on a silica-based optical waveguide substrate (not shown). The fixed phase distribution providing circuit 40
It is composed of an optical distributor 420 using a silica-based optical waveguide and a delay line 230 using a silica-based optical waveguide having a predetermined line length. The optical multiplexing section 50 includes an intersection section 51 using a silica-based optical waveguide and an optical multiplexer 320. The outputs of the corresponding delay lines of the fixed phase distribution providing circuits 40 are multiplexed by the optical multiplexer 320 via the intersections 51 and sent to the corresponding light receivers.

The signal light is input to the optical path selection switch 100 and sent out to one fixed phase distribution providing circuit 40 for setting a predetermined phase distribution. In the fixed phase distribution providing circuit 40, the signal light is distributed to N paths according to the number of radiating elements by the optical distributor 420, and a predetermined phase is provided to each of the N delay lines 230 arranged in each path. Then, the light is transmitted to the light receiver via the corresponding optical multiplexer 320. That is, in the configuration of the present embodiment, by selecting one of the fixed phase distribution applying circuits 40 with the optical path selection switch 100,
A phase distribution corresponding to the length distribution of the delay line 230 is set.

In this embodiment, the number of optical path selection switches can be significantly reduced as compared with the first and second embodiments. As a result, even if the optical path selection switch is constituted by a thermo-optic effect optical switch, the power consumption can be significantly reduced. On the other hand, in the present embodiment, the number of delay lines is larger than in the past, and further intersections are generated. By doing so, it is possible to respond without any trouble.

In a large-sized phased array beam forming circuit for which the number of radiating elements is assumed to be several hundreds for use on a satellite or the like, each circuit element is divided and manufactured, and the circuit elements are connected by an optical fiber. . In this case, the configuration of this embodiment has an advantage that the fiber connection is easy and the phase distribution of the signal is not affected. That is, it is necessary to provide a precise line length for each path in a path subsequent to the optical distributor for distributing the signal light to each radiating element, and it is preferable that the subsequent stage from the optical distributor is not divided as much as possible. In the configuration of this embodiment, only the fixed delay line group exists at the subsequent stage of the optical distributor, and it is easy to set a precise line length for each path.

Further, in the configuration of this embodiment, the optical path selection switch can be formed separately from other circuit elements, so that a material different from that of the quartz-based optical waveguide may be used. Configuration can be selected. For example, using a LiNbO ₃ waveguide switch, a semiconductor switch, or the like enables high-speed operation and integration of a light source and an optical path selection switch.

[0043]

As described above, the beam forming circuit for a phased array of the present invention has the following effects. A delay line group having a precise delay amount difference can be formed with low loss and without loss variation due to a path. Further, environmental stability against temperature, humidity, and the like can be remarkably improved.

By integrally forming a large-scale circuit on a large-area substrate, the degree of freedom in selecting the amount of delay can be significantly increased. By using a silica-based optical waveguide, a plurality of fixed phase distribution providing circuits can be formed, and one of them can be selected and used. This makes it easy to set a precise line length for each path, and can greatly reduce the number of optical path selection switches that consume large power.

Therefore, it is possible to realize a beam forming circuit for a phased array which is excellent in low loss, production stability and environmental stability and has a high degree of freedom in selecting a delay amount for enabling flexible beam steering. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration example of thermo-optic effect light switches 120 and 310.

FIG. 3 is a block diagram showing the configuration of a second embodiment of the present invention.

FIG. 4 shows an optical gate switch 130 when the number of delay lines is four.
The figure which shows the example of a structure of.

FIG. 5 is a block diagram showing a configuration of a third embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration example of a conventional beam forming circuit for a phased array using an optical circuit.

FIG. 7 is a block diagram showing a configuration example of a conventional variable phase shifter.

FIG. 8 is a diagram showing a study example of a variable phase shifter using a semiconductor optical waveguide.

FIG. 9 is a block diagram showing a configuration example of a conventional variable phase shifter.

FIG. 10 is a diagram showing a study example for solving a problem of a configuration example of a conventional variable phase shifter.

FIG. 11 is a block diagram showing a study example of a variable phase shifter using a silica-based optical waveguide.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light source 2 beamforming circuit for phased array 3 light receiver 4 amplifier 5 radiating element 6 MSM detector 7 semiconductor substrate 8 quartz-based optical waveguide substrate 10 light distributor 20 variable phase shifter 30 optical delay line selection circuit 40 fixed phase distribution giving circuit Reference Signs List 50 optical multiplexing part 51 intersection part 100 optical path selection switch 110 2 × 2 electro-optical effect switch 120 thermo-optical effect optical switch 121 3 dB directional coupler 122 arm waveguide 123 heater electrode 124 power supply 130 optical gate switch 131 optical four branch circuit 132 semiconductor gate array 200 fixed delay line 210 delay line using semiconductor optical waveguide 220 optical fiber delay line 230,231 delay line using silica-based optical waveguide 300 optical multiplexer 310 thermo-optic effect optical switch 320 silica-based optical waveguide Optical multiplexer 400 used Optical splitter 410 Optical star coupler 420 Optical splitter using silica-based optical waveguide

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-261902 (JP, A) JP-A-3-6504 (JP, A) JP-A-1-267526 (JP, A) JP-A 64-64 68103 (JP, A) Special Table Hei 6-506814 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01Q 3/36 G02F 1/01 H01Q 3/26

Claims (3)

(57) [Claims] 1. A phased-array beam forming circuit for dividing a transmission signal light into a plurality of paths, applying a predetermined amplitude and phase to the signal light of each path, and supplying the signal light to a plurality of radiating elements. And a plurality of variable phase shifters connected in parallel at the subsequent stage, wherein the variable phase shifter includes a thermo-optic effect optical switch. One or more optical delay line selection circuits connecting the optical path selection switches used and the delay lines using a plurality of silica-based optical waveguides having different line lengths are connected in cascade, and the final stage optical delay line selection circuit is connected. A beam forming circuit for a phased array, characterized in that it is connected to an optical path selection switch using a thermo-optic effect optical switch or an optical multiplexer. 2. A beam shaping circuit for a phased array which divides a transmission signal light into a plurality of paths, applies predetermined amplitude and phase to the signal light of each path, and supplies the signal light to a plurality of radiating elements. And a plurality of variable phase shifters connected in parallel in the subsequent stage, wherein the variable phase shifter uses an optical gate switch. A configuration including an optical path selection switch, a delay line connected to a subsequent stage using a plurality of silica-based optical waveguides having different line lengths, and an optical multiplexer using a silica-based optical waveguide connected to a subsequent stage. A beam forming circuit for a phased array. 3. A beam forming circuit for a phased array which divides a transmission signal light into a plurality of paths, applies a predetermined amplitude and phase to the signal light in each path, and supplies the signal light to a plurality of radiating elements. And a delay line using a plurality of silica-based optical waveguides of different line lengths connected in parallel at the subsequent stage, each having a predetermined length. A plurality of fixed phase distribution providing circuits for setting a phase distribution, and one of the plurality of fixed phase distribution providing circuits for transmitting the transmission signal light.
An optical path selection switch for inputting the output signal to the corresponding one of the plurality of fixed phase distribution providing circuits, and an optical multiplexing unit using a silica-based optical waveguide that multiplexes the corresponding delay line output and supplies the multiplexed output to the corresponding radiating element A beam forming circuit for a phased array.