JPH0222630A - Optical phase distribution control element - Google Patents

Abstract

PURPOSE:To obtain the element which has no mechanically moving parts, is small in size and make space modulation of the light controllable from the outside by providing a carrier density distribution control means which can form carriers of the density distribution of the prescribed pattern nonuniform along the transverse direction orthogonal with a light propagation direction. CONSTITUTION:The density distribution of the carriers generated in a light guide 13 to allow the passage of the light to be space-modulated by using a stock capable of generating the carriers is controlled to control the phase distribution of the light propagating in the waveguide. The optical phase distribution control element 10 is formed by using an n-GaAs substrate as a substrate 11, and laminating an n-AIxGa1-xAs layer 12 having a low refractive index as a lower light confining layer, an AIyGa1-yAs layer 13 having a high refractive index as the light guide, and p-AIzGa1-zAs layer 14 having a low refractive index as an upper light confining layer. The deflection angle is controllable by the current ratio to be impressed to a pair of control electrodes 21-1, 21-2 in this case. The light phase distribution control element with which the high- speed operation can be expected and which allows the easy control from the outside while the size is small is obtd. in this way.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a solid-state element that spatially modulates light, that is, it scans or switches the deflection direction of light, or changes the focal point when converging. On the other hand, regarding solid-state devices that can vary the divergence angle during divergence, in particular, by applying external electrical control signals or optical control signals, the various types described above can be achieved without using mechanically movable parts. This invention relates to an element improved to control the optical phase distribution in an optical waveguide so as to perform a spatial modulation function.

<Prior art> Light is highly anticipated as an information transmission medium in the future, but when dealing with such optical signals, it is necessary to use devices that deflect or scan the light in a predetermined direction, or to change the convergence position, that is, the focal point. A device that can make the divergence angle variable or conversely, a device that can make the divergence angle variable is required.

However, looking at the devices that have been developed to meet this need, there are devices that rotate a reflecting mirror for deflection and scanning, devices that use medium compression waves using ultrasonic waves, and devices that use angle control for convergence and divergence. Regarding this, there was a device that moved and adjusted a converging or diverging lens in the optical axis direction.

<Problems to be Solved by the Invention> As mentioned above, conventional devices in this type of field, except for devices that utilize compression waves in an ultrasonic medium, do not require any methods such as rotating a reflecting mirror or moving a lens. It is also taken care of by the mechanical system.

Therefore, as is usual for such mechanical systems, their operating speed is so slow that it does not pose a problem compared to the speed at which optical signals are handled, so no matter how high-speed optical signals are promoted, However, if a single system is constructed that includes such devices, all of these advantages will actually be lost.

In addition, such mechanical systems have problems in their angular resolution and accuracy compared to the geometrical dimension orders of circuit systems that use optical signals.First, there are many causes of failure, and maintenance is difficult. Poor reliability.

In contrast, deflection and scanning devices that utilize ultrasonic compression waves are the only so-called solid-state devices, and do not have mechanically movable parts.

Therefore, although this device is desirable in that respect, it has drawbacks such as a small deflection angle and difficulty in miniaturizing the device, so it cannot be said to be a very practical device.

The present invention was made in view of the above circumstances, and as an element that spatially modulates light, (1) there are no mechanically movable parts;

- Deflection direction, convergence focal point position, divergence angle, etc. can be controlled easily and with good controllability using external electrical control signals and optical control signals.

■There are no wood-related factors that hinder the miniaturization of the element itself.

■Can be reliably manufactured using existing technology.

The objective is to provide a solid-state device that satisfies all of the following main requirements.

Means for Solving the Problems> In order to achieve the above object, the present invention uses a material capable of generating carriers in a leading wave path that passes light to be spatially modulated, and changes the density distribution of carriers generated in the leading wave path. We propose a device that controls the phase distribution of light propagating in a waveguide.

In other words, with such a device, the shape of the carrier density distribution can be controlled at least in one-dimensional direction perpendicular to the light propagation direction, and desirably, the shape along the light propagation direction can be taken into consideration, and a predetermined two-dimensional shape can be obtained. By forming a distribution pattern, you can control light deflection, scanning control, convergence focus position,
Variable control of divergence angle.

In addition, in order to generate carriers in the optical waveguide and control its density distribution as described above, for the waveguide,
This can be done by applying a voltage to an electrode provided to allow carrier injection and injecting a predetermined amount of current, or by controlling the necessary strength through a window of a predetermined shape opened in a predetermined waveguide region. This can also be done by irradiating light.

<Operations and Effects> In the present invention, the density distribution of carriers intentionally generated in an optical waveguide is controlled to a predetermined pattern.

Therefore, for example, even if we consider only the linear distribution shape in the lateral direction perpendicular to the propagation direction of light propagating in the waveguide, if the carrier density changes in the lateral direction, the refractive index in the lateral direction in the waveguide The distribution, gain distribution, etc. also change depending on the carrier density pattern at this time.

When the refractive index changes in the lateral direction, the phase of the light propagating in the waveguide also relatively advances or lags at each lateral position, and the overall phase distribution changes. Change.

If this happens, the light will be directed at a certain angle, converged, or diverged depending on the phase distribution and ultimately the shape of the generated carrier density distribution.

Even if the gain distribution in the optical waveguide changes according to the given carrier density distribution, the optical intensity will become non-uniform, which will affect the optical phase distribution from that point onwards, allowing for deflection, convergence, and divergence. becomes.

In other words, since the above mechanism is expected, the element of the present invention is called an optical phase distribution control element. In other words, even if the starting point of controlling the carrier distribution in the optical waveguide is the same, there are differences in the intermediate mechanism, whether it is a change in the shape of the refractive index distribution or a change in the gain distribution, or whether both are synergistic. Because there are various cases such as whether the light acts on the waveguide, rather than the name of the refractive index distribution control element or gain distribution control element for the leading waveguide, it is rather the light itself that is the reason for spatially modulating the light. It seems appropriate to use a name that focuses on the phase distribution of .

Of course, the horizontal one-dimensional phase distribution control in the above explanation can be expanded two-dimensionally, and if it is applied continuously along the light propagation direction, the resulting light deflection, convergence, and divergence. Functionality is further enhanced. This can be accomplished by providing electrodes for applying control voltage (current) and windows for controlling light irradiation continuously along the length of the waveguide. If the lateral carrier density distribution at each point along the axial direction can be controlled differently from other points depending on the electrode shape and window shape, wider controllability and design freedom can be obtained. .

In any case, according to the optical phase distribution control element of the present invention, as a solid-state element that applies predetermined spatial modulation to incident light and irradiates it, all of the drawbacks of the conventional examples described above can be eliminated. can do. The effects of the present invention can be listed as follows.

■For spatial modulation of light, a procedure of generating carriers in the waveguide through which the light passes and controlling its density distribution is adopted, resulting in high-speed operation that is incomparable to modulation devices using conventional mechanical systems. This can be expected without compromising the fundamental advantage of optical signals themselves, which is high speed.

■Since there are no mechanically moving parts, the element configuration can be simplified, and failure factors are greatly reduced, so sufficient reliability can be achieved. In principle, there is no factor that prevents miniaturization.

■Optical phase distribution can be easily controlled from the outside depending on the voltage applied to the control electrode or the value and position of the control current passed through the element, the shape of the electrode, the intensity of the control light, the position and shape of the control light, etc. can be controlled.

■The minimum requirements of the present invention for optical waveguides are:
The only fact is that it is a material that can generate carriers, so if it is made of a suitable semiconductor, the device of the present invention can be used on a common substrate or in combination with semiconductor lasers and other optical integrated circuit devices. , it can contribute to the realization of extremely multi-functional, high-performance devices such as so-called opto ICs and OE-ICs.

■The principles and structural examples of generating carriers in a predetermined material layer by applying a current or irradiating it with light are well known, so by utilizing these existing techniques, the device of the present invention The manufacture itself is simple.

(Embodiment) FIG. 1 shows an embodiment of an optical phase distribution control element IO constructed according to the present invention.

In the present invention, as mentioned above, the minimum requirement for the optical waveguide 13 used in the device of the present invention is that it be made of a material that can generate carriers therein.
In general, it is preferable to use semiconductors in view of handling, manufacturing, processing, etc., and silicon-based materials are also suitable, but in this example, AlG, which has been attracting a lot of attention recently, is
The aAs system is used.

In accordance with this, the example of the element structure shown in the first drawing will be explained while giving specific examples of materials. First, as the substrate 11, n
- Using a GaAs substrate, a lower optical confinement layer (cladding layer) of n-AlxGa+- with a low refractive index is sequentially formed on the substrate.
xAs layer 12, high refractive index AI, Ga,
-, AS layer 13, p-A1 with a low refractive index as an upper optical confinement layer (cladding layer). Ga+- and As layers 14 are laminated.

In the case of a normal optical waveguide device structure, it is sufficient to have the above-mentioned upper and lower optical confinement layers 12 and 14 and a waveguide layer 13 with a relatively high refractive index sandwiched between them, and it is necessary to take into account the conductivity type in particular. However, in this embodiment of the present invention, carriers are first injected or generated into the waveguide 13 by current injection, so as mentioned above, the upper and lower optical confinement layers 12 and 14 are pn It is adapted to form a junction.

In addition, since it is used by passing a current in the same way, a control electrode 21- for current injection and carrier distribution control, which will be described later, is used.
, 21-2, in order to make good ohmic contact,
On the upper optical confinement layer 14 is a p-Ga conductive layer.
A high conductivity layer 5 of As is formed, and a SiN protective insulating film 16 is formed thereon, while a common electrode 20 made of germanium-doped gold or other suitable material is formed on the back surface of the substrate 11.
are provided for ohmic contact.

In the illustrated case, it is formed on the protective insulating film 16. There is a pair of control electrodes for current injection and carrier distribution control.
1-r and 21-z are attached, but these are geometrically spaced apart from each other in the direction perpendicular to the light propagation direction, and are electrically insulated along the light propagation direction. both extend parallel to each other. The material is chromium and α, but it may be a laminated material of chromium and gold.

However, in each control electrode 2L, 2L2, each control current 1. The effective area for implanting I2 is the area that is in ohmic contact with the conductive layer 15 below through the opening made in the insulating film 16 below. In Figure 1,
The end face portions of the effective electrode portions 2L, 2L2 are shown.

Furthermore, since the area immediately below the waveguide 13 corresponding to this area is used in the later explanation, similarly in FIG. ±x2. It is shown as an end face area defined by two points each separated by ±×2.

However, if the control electrodes as carrier density distribution control means are considered as a pair in the current flow direction, the common electrode 20 provided on the back surface of the first illustrated element is replaced by each control electrode 2L provided on the top surface. 2L2.

Incidentally, antireflection films 17 and 17 made of a suitable material are also attached to both end surfaces of the waveguide in the optical axis direction, as is normally provided in this type of optical waveguide technology.

As previously explained in the section of the function, if the lateral refractive index distribution in the waveguide 13 changes, the incident light Ll entering the waveguide 13 of the first illustrated structure will change as it propagates through the waveguide. The phase distribution also becomes non-uniform due to the phase leading and slowing relationships in each part in the lateral direction, and as a result, light is emitted from the opposing end face. is deflected, converged, or
It becomes something that emanates. This holds true even if the gain distribution in the waveguide changes.

On the other hand, the refractive index distribution and gain distribution are determined or controlled by the wavelength of propagating light and the carrier density within the waveguide.

Therefore, using the element lO shown in the first figure, each control electrode 2L+
, 21-2 toward the common electrode 20, the following operation can be caused.

First, a current ff1 with the same polarity and the same value forward biases the upper and lower optical confinement layers 14.12 from both control electrodes 2L, 2L2.
When I+ and h are supplied symmetrically, if the electrical resistances of the conductive layer 15 and the upper optical confinement layer 14 are properly made, the injected current will spread uniformly in these layers, so that as shown in FIG. As shown in (A), the waveguide 13 below
±x1. respectively from the optical axis center. With respect to the region immediately under the current injection which is defined by two points separated by ±×2, the carrier density becomes uniform in the region between them.

Under these conditions, the refractive index and gain are both uniform in the region -X2<x<X2, and therefore the incident light propagates without being particularly subjected to spatial modulation such as deflection, and the outgoing light. is almost the same as the incident light L1 in its optical axis direction and width.

However, if we try to increase the amount of current injected into the device through one electrode 21-1 and make it asymmetrical in relation to the current injected through the other control electrode 21-2, then
As shown in FIG. 2(B), the carrier distribution within the waveguide 13 has a slope even in the same region -X2<x<X2, and the region immediately below the control electrode 22-9 is X2<X<-X.
The carrier concentration is higher in I than in other parts, resulting in a kind of unimodal lateral distribution pattern.

The light propagating in the waveguide 13 under such conditions is deflected by a corresponding angle by subjecting the phase distribution to corresponding modulation, as described above. In other words, the deflection angle is the same as that of the pair of control electrodes 2L, 2L2.
It can be controlled by the current ratio applied to.

FIG. 3 shows an example of the characteristics (far-field image) of an experiment to prove this, and for the upper and lower optical confinement layers 12 and 14, the current value 1. The current value I is increased from =-10mA to 9011+A in 10IIIA steps, while the other current value 2 is increased from 90+aA to 10mA.
The upper and lower optical confinement layers 12 are similarly reduced in steps,
Regarding 14, the current value that becomes reverse bias is I2 = IO
Seven combinations were taken, varying up to ImA.

As is clear, as the current value 11 increases every 10 mA step and therefore the current value 12 decreases every 10 mA step, the deflection angle of the light changes continuously and favorably from about +3° to about 13°. It is variably controlled while maintaining its properties.

For these reasons, the phase distribution control element IO of the present invention has the following characteristics:
Light beam deflection angle variable device, each current value 1, , I
It can be seen that by scanning 2 as in the above example, it can be used as a light beam in-plane scanning device.

On the other hand, in the device IO shown in FIG. 1, the electrical resistance of the conductive layer 15 and the upper optical confinement layer 14 thereunder is intentionally increased, or for this purpose, each effective electrode portion 2L, , When ion implantation or etching is performed on a region of corresponding size under the part where 22-2 contacts to form a local high resistance part, the current injected into the waveguide 13 is concentrated in the part directly under the current injection. , Figure 2 (C)
, As shown in (D), the carrier distribution is bimodal with a concavity in the center (center of the optical axis).

In this case, the light propagating in the waveguide 13 is subjected to convergence or divergence, and therefore the present element 10 performs a kind of lens action, as shown in the relationship between FIGS. 2(C) and 2(D). Thus, as the amount of current injection increases and the height of each peak (carrier concentration at that point) increases, the focal position becomes shorter and the divergence angle becomes wider.

To demonstrate this, FIG. 4 shows experimental characteristics when this element functions as a variable focus element.

When the amount of control current supplied through each control electrode z1-+ and 2L2 is both 30 mA, the focus is almost at a position 1150 μm apart in the optical axis direction from the output end face of this element. When both currents I, , I are increased to 60+aA, the focal length is shortened to about 30-1.

From these facts, it can be seen that the present element 10 can also be used as a variable focus element for a light beam controlled by an external electric signal.

Furthermore, although not shown, if a new control electrode is provided between the control electrodes 2L, 212, and a current is intensively passed through this central electrode, a carrier distribution with a peak in the center is formed.
It can be used as a light beam divergent element, and its divergence angle can also be controlled by electrical signals.

Furthermore, Figure 2 (A), (B) and the same figure (C)
, (D) can be used in conjunction with a device that can obtain a variable deflection angle with a variable focal point, for example, as one way to use this element IO.

Regarding the control electrode, for example, regarding the optical axis, Fig. 2 (C)
, If it is sufficient to obtain a carrier distribution that is symmetrical in the horizontal direction as shown in (D), the pair of control electrodes shown in FIG.
Alternatively, they may be electrically connected to each other so as to straddle the waveguide using a conductive line pattern of an appropriate thickness.

However, in such a case, it can be considered that a substantially single control electrode is used and its pattern shape is appropriate for forming a bimodal carrier density distribution.

And from the point of view of a single electrode, for example, the second
When used as a deflection device with unimodal characteristics as shown in Figure (B), there is a special case, that is, the output light beam L. For applications where it is only necessary to be able to deflect from the non-deflected state to either the left or right side, the control electrode 21-, shown in the first figure.

A configuration in which either one of 21-2 is not provided is also conceivable.

On the other hand, in order to control the carrier distribution more precisely, for example, the pair of control electrodes 21-+ and 2L2 shown in the first figure arranged in the direction perpendicular to the optical axis can be formed from a plurality of control electrodes arranged in parallel independently of each other. It can also be configured.

Furthermore, taking into consideration the change in shape along the light propagation direction, it may be possible to form the shape of the control electrode itself into a special geometric pattern. FIGS. 5(A) and 5(B) show an example of such a case, and in FIG. 5(A), the pair of control electrodes 2L+ and 21-2 have a continuous triangular wave or prism shape when viewed in the optical axis direction. However, they are separated from each other by a groove.

In such a case, as in the first illustrated configuration example, the lateral carrier density distribution is continuously formed along the optical axis direction,
As the traveling wave progresses, it continues to be integrally influenced by the specific carrier density distribution, whereas the incident light has a relatively low polarity that corresponds to the area where the current ■2 is flowing, for example. From the area, the light is deflected only every time it crosses a triangular contour part that enters a relatively high polarity area where the current 1 is flowing, but the number of these wave shapes increases and the light crosses this contour part. By increasing the number of times, a sufficient deflection angle can be obtained.

Similarly, as shown in FIG. 5(B), a plurality of control electrodes are arranged in convex lens-shaped electrode portions 21-2 arranged at predetermined intervals in the optical axis direction, and grooves are placed around them. When configured from the surrounding portion 21-1, light is emitted by controlling the amount of current or current ratio given to each control electrode. With respect to its focal position f. It has also been confirmed that it is possible to realize an element with a variable divergence angle or a variable divergence angle.

From now on, II of various numbers and shapes can be prepared as necessary.
Now that the present invention has been disclosed, what can be achieved with the J control electrode is:
This will be obvious to those skilled in the art.

By the way, the material of the waveguide 13 used in the present invention may be any material as long as it can generate carriers inside it, as mentioned several times before, but it may be used as a material combination such as the material combination shown in the first figure.
If a suitable semiconductor is selected, integral molding or integration with semiconductor devices such as semiconductor lasers and photodetectors, and even if not mechanical combinations and connections, will be facilitated.

FIG. 6 schematically shows some examples of such cases. However, in this figure, the element I according to the present invention
Regarding O, only the waveguide 13 and the presence of an antireflection film 17 on one end surface are shown only schematically. This is because the present invention does not indicate an example of structural modification of the device itself.

However, first, the structure shown in FIG. 6(A) uses a diffraction grating for the reflection mechanism 31 or uses a predetermined repetition period of the refractive index, thereby achieving distributed Bragg reflection that does not require a reflection mirror on the end face. This figure shows a case in which the optical phase distribution control element 10 of the present invention is integrated into the output end face of a semiconductor laser 30 of a type (DBR) type or a distributed feedback type (DFB).

In other words, since such a laser 30 does not require a reflecting mirror on the laser side output end face as described above, in FIG. Although line 32 schematically illustrates a coupling portion, in reality this coupling portion 32 can be formed continuously from a series of semiconductor materials, connecting the active layer 33 of the semiconductor laser 30 and the waveguide of the present invention. 13 can be formed as a series of layer regions. This is extremely desirable in that a state with the least coupling loss can be obtained.

On the other hand, in the case of a normal semiconductor laser that requires Fabry-Bello type resonators or reflecting mirrors on both end faces in the optical axis direction, the sixth
As shown in Figure (B), for example, a semiconductor laser 4
After forming the active layer portion 43 of the semiconductor laser 40 and the waveguide 13 of the present device 10 in series and laminating the layer structures necessary for forming each device, the coupling portion 4 of the semiconductor laser 40 with the present device 10 is formed.
2, a groove 41 for forming one reflecting mirror of the semiconductor laser;
It is sufficient to excavate it by reactive ion etching or the like to form a vertical wall surface.

In fact, since the technique of forming a vertical wall surface corresponding to the arm opening surface by etching has already been established in the past, the structure shown in FIG. 6(B) can be easily obtained. It will be done.

Furthermore, the sixth
Figure (C) As shown in the figure, in a more primitive manner, the lasers 30, 40 and the device of the present invention are placed on a suitable fixed table 50.
The connecting portion 42 may be formed by fixing the two in a butt position and positioning them.

Furthermore, it will be understood that, from the various methods described above, coupling with other opto-electrical elements such as a photodetector can be easily performed in place of the semiconductor laser.

By the way, in all of the embodiments of the present invention described so far, the carrier density distribution control means for generating carriers in the waveguide 13 and controlling the density distribution is the upper and lower optical confinement layers that sandwich the waveguide between the upper and lower sides. and a control electrode pair 21-+ for intentionally supplying current to this p-n junction.
, 20: 21-2, 20, but instead of such a current excitation type, the optical phase distribution control element 10 of the present invention may be operated as a light excitation type element that introduces the concept of control light. can.

FIG. 7 shows an embodiment in which the optical phase distribution control element of the current excitation type shown in FIG. The lower optical confinement layer 12 with a low refractive index
After forming the high refractive index waveguide 13 and the low refractive index upper optical confinement layer 14, a light shielding layer 18 is formed thereon, and the effective electrode portion 22 of the first illustrated embodiment is formed on the light shielding layer 18.
Openings or windows 2L, 2L2 are opened in areas corresponding to -r, 22-2, and these windows 2L, 2:
12, a control light tc-tlLC- having a photon energy larger than the energy gap of the waveguide 13
It is designed to irradiate 2.

Of course, unlike the current excitation type described above, there is no need to have a current injection mechanism such as a pn junction, so in principle a wider selection range is given to the materials of the waveguide structure and the optical confinement layers above and below it. However, considering the convenient relationship in combination with other semiconductor lasers, etc., even as an optically pumped type,
Semiconductor-based materials such as silicon-based materials and aluminum-gallium-arsenic materials are desirable.

Even in such a structure, although there is a difference that carriers excited in the waveguide 13 are caused by optical excitation, the functions, effects, and modifications already described for the current type can be applied almost as they are.

For example, if the light intensities of the control lights t, c-1+Lc-z emitted through the goodwill 23-1.2L2 are made equal and the light intensities are increased symmetrically, the results will be as shown in Fig. 2(C), ( D
) and FIG. 4, a lens effect can be expected, and it can be applied as a variable focus light beam converging device or a variable divergence angle light beam emitting device. Especially in this case,
The control lights LC-1 and LC-2 to be irradiated may be uniform irradiation light onto the upper surface of the element.

On the contrary, if each control light LC-1+'C-2 is irradiated from an individual optical system with its light intensity individually changeable, the asymmetry of the control lights LC-1+'C-2, that is, the magnitude of their light intensities. Depending on the ratio, it becomes possible to use the device as a light beam output device or a light beam scanning device with a variable deflection angle, as explained with reference to FIGS. 2(B) and 3.

In the case of this photo-excitation type embodiment, various controls similar to those of the current-excitation type can be performed by making the shape of each window into a special pattern based on the idea explained with reference to Fig. 5. Moreover, as shown in FIG. 6, it is of course possible to integrate or integrate with other opto-electrical elements.

Furthermore, as can be understood by considering the configuration in which the control electrode portion and the window for introducing control light coexist, the present invention can also provide an element that uses both current excitation and optical excitation.

In the current excitation type of the first embodiment, a pn junction using upper and lower optical confinement layers is used as part of the current injection mechanism, but although this is certainly desirable, it is not essential. It is sufficient that these layers are made of a material that allows control current to be injected into the waveguide 13 via the control electrode.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an optical phase distribution control element configured to control spatial modulation of light using a control current as a first embodiment of the present invention. FIG. 2 is an explanatory diagram of the correlation between the carrier excitation energy (current) and the lateral carrier distribution obtained in the waveguide with respect to the application site. FIG. 3 is an explanatory diagram of the operation using a far-field image obtained when the device of the present invention is used as a light beam deflection device. FIG. 4 is an explanatory diagram of the operation when the device of the present invention is used as a variable focus optical beam focusing device. FIG. 5 is an explanatory diagram of an example in which the control electrode shape is specialized. FIG. 6 is an explanatory diagram when the device of the present invention is combined with a semiconductor laser. FIG. 7 is a schematic configuration diagram of an optical phase distribution control element in an embodiment of the present invention modified so that spatial modulation of light is controlled by control light. It is. In the figure, IO represents the optical phase distribution control element of the present invention as a whole;
11 is a substrate, 12 is a lower optical confinement layer, 13 is a waveguide,
14 is an upper optical confinement layer, 15 is a conductive layer, 18 is a light shielding layer, 20 is a common electrode constituting the unipolar side of the control electrode, 2L
, , 2L are control electrodes, 22-, , 22-2 are effective electrode portions, 2:LI, 2L2 are windows for control light irradiation. Designated Agent Director, Electronics Technology Research Institute, Agency of Industrial Science and Technology

Claims (3)

[Claims] (1) A waveguide capable of propagating light incident on one end surface to the other end surface and outputting the light; In the waveguide, in the light propagation region, at least along a lateral direction perpendicular to the light propagation direction, An optical phase distribution control element comprising: carrier density distribution control means capable of generating carriers having a non-uniform density distribution in a predetermined pattern. (2) Optical phase distribution control according to claim 1, characterized in that the carrier density distribution control means has a pn junction formed by an optical confinement layer sandwiching the upper part of the waveguide, and a control electrode in ohmic contact with the pn junction. element. (3) Claim 1, wherein the carrier density distribution control means has a window means capable of introducing control light into the waveguide.
The optical phase distribution control element described in .