JP2000151014A - Optical function element and optical communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical function element of high performance at low cost, wherein such concept which is related to a conventional optical function element as 'the number of resonator being one' is significantly developed. SOLUTION: Along a signal resonator structure or waveguide structure, a separate resonator structure is formed in another direction. Especially a resonator structure of radiation mode which is irradiated from a waveguide, comprising at least secondary diffraction lattice 2, is configured. The radiation mode is amplified with another amplification mechanism 3, and furthermore is returned to the waveguide again using a reflective mechanism 4. Since the radiation mode radiates on both sides of the waveguide, it is desired that the reflective mechanism 4 be provided on both. With such a unique resonator configuration as the base, an amplifier, optical modulator, laser oscillator, coupler, or optical communication device using them are realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical functional device and an optical communication device. More specifically, the present invention is based on a waveguide mechanism having a second or higher order diffraction grating, and has an optical amplifier having a resonator structure for amplifying a radiation mode radiated from the waveguide mechanism with high efficiency. The present invention relates to an optical function element such as a modulator and a laser oscillator and an optical communication device using the same.

[0002]

2. Description of the Related Art As an optical functional element having a waveguide for guiding an optical wave, for example, a semiconductor laser can be cited. An ordinary semiconductor laser forms a resonator with one waveguide structure. In addition, a semiconductor optical amplifier (SOA: Semicond
uctor Optical Amplifier) also has one waveguide structure. That is, in the conventional optical function element, the concept of "one resonator" was premised.

[0003]

Since this concept is common sense, the description of the configuration of the conventional optical functional device will be omitted with reference to the drawings. There is no major problem with these conventional concepts and concrete structures. However, the drawback of the prior art is that it has a single resonator structure, and thus lacks expandability and flexibility.

[0004]

SUMMARY OF THE INVENTION The present invention is a significant leap of such a conventional concept. That is, the concept is to form another resonator structure in another direction along one resonator structure or waveguide structure. In particular, radiation modes (radiats) emitted from waveguides with holograms
It is based on the concept of configuring a resonator structure in the ion mode. Here, "hologram" is referred to as "a fine structure of complex refractive index or complex reflectance (imaginary part represents loss / gain) capable of generating a spatially controlled radiation mode".
Is defined. The “second-order or higher diffraction grating” employed in a specific example described in detail below is only one form of “hologram”. This is because the diffraction grating is a structure based on a uniform periodic structure mainly composed of a real part having the most simplified refractive index. Since the understanding is easy as described above, the description will be given below with reference to a specific example using a diffraction grating.

On the other hand, as will be described in detail later, the case where the period of the diffraction grating is delicately changed in the waveguide direction or the provision of a phase shift is also an important embodiment of the present invention. Collectively, these variations are the "hologram" as defined above.

Next, the novel resonator structure of the present invention will be described in more detail. Conventionally, it has been common sense that once a waveguide is formed, the resonator structure of the waveguide is unidirectional. When the waveguide has a second-order or higher diffraction grating, the radiation mode is radiated from the entire waveguide as a beam having a narrow spread in a predetermined direction. Attention is paid to the radiation modes having the same characteristics, and a new radiation mode resonator is constructed, and is entangled with the original waveguide resonator.

That is, the present invention seeks to develop a completely new function, rather than improving the disadvantages of the prior art.

Specifically, the optical functional device of the present invention is a waveguide mechanism that guides a light wave and has a gain or a loss,
A first waveguide mechanism having a hologram capable of generating radiation mode light by combining with the guided light wave, and an amplification mechanism for amplifying and emitting the radiation mode light emitted from the first waveguide mechanism And a first reflection mechanism that reflects the radiation mode light emitted from the amplification mechanism toward the first waveguide mechanism.

Here, the amplifying mechanism is configured so that the first guided mode of the guided light wave is a single transverse mode.
Characterized in that it is provided apart from the waveguide mechanism. That is, the radiation mode is stabilized by maintaining the single transverse mode in the waveguide mechanism, and the coupling at the time of extracting light from the end face of the waveguide mechanism can be ensured.

[0010] The amplifying mechanism may give not only a gain effect but also a loss effect to the radiation mode light.

Further, the optical function device according to the present invention is characterized in that the optical function device further comprises a phase control mechanism for controlling a phase of the radiation mode light reflected by the first reflection mechanism.
With such a phase control mechanism, the reflected light from the reflection mechanism can be coupled to the first waveguide mechanism via the diffraction grating with high efficiency.

[0012] Here, the phase control mechanism also performs the first mode so that the guided mode of the guided light wave becomes a single transverse mode.
In this case, a single transverse mode in the waveguide mechanism is maintained, the radiation mode is stabilized, and coupling at the time of extracting light from the end face of the waveguide mechanism can be ensured.

Further, at least two or more of the waveguide mechanism, the amplification mechanism, the first reflection mechanism, and the phase control mechanism may be realized by a common structure. For example, by providing an active layer having a gain as a part of the waveguide mechanism, it is possible to have both functions of the waveguide mechanism and the amplification mechanism.

A second hologram is provided substantially in parallel with the first waveguide mechanism and has a second hologram. The second hologram is optically coupled to the first waveguide mechanism via the second hologram. A waveguide mechanism is further provided.

Here, as a preferred embodiment of the present invention, the hologram is a diffraction grating of second order or higher.

Further, the diffraction grating may have a blaze angle. That is, if the cross-sectional shape of the diffraction grating is made asymmetric, selectivity is generated in the direction of the light wave, and an optical isolator and a directional coupler can be formed.

Further, by providing a discontinuity of the phase, that is, a phase shift in the diffraction grating, the distribution of the waveguide mode and the radiation mode in the waveguide structure can be adjusted.
No.

Further, by modulating the amplification factor of the amplification mechanism, the refractive index of the waveguide mechanism, and the reflectance or the refractive index of the reflection mechanism, the resonance condition of the resonator formed perpendicular to the waveguide mechanism is optimized. Can be

Further, by changing the period of the diffraction grating along the waveguide direction of the waveguide mechanism, it becomes possible to resonate and amplify light of a plurality of wavelengths. Further, functions such as a light emitting element, a multiplexer, and a demultiplexer for wavelength division multiplexing communication can be realized.

The same operation and effect can be obtained by the amplification factor of the amplification mechanism,
It can also be realized by changing the refractive index of the waveguide mechanism, the reflectance of the reflection mechanism, and the like along the waveguide direction.

Further, the same operation and effect can be realized even when a plurality of the phase control mechanisms for adjusting the relative phase exist along the direction of the waveguide, and each of them can be independently modulated.

Alternatively, a plurality of the amplifying mechanisms may be provided along the direction of the waveguide, and each of the amplifying mechanisms may be independently modulated.

Alternatively, it can be realized by providing a plurality of mechanisms for modulating the refractive index of the waveguide mechanism along the direction of the waveguide and independently modulating each.

Alternatively, a plurality of mechanisms for modulating the reflectivity of the first reflection mechanism may be provided along the direction of the waveguide, and may be independently modulated. On the other hand, the optical functional device of the present invention can be positioned as having a transmission line through which an optical signal propagates in the waveguide mechanism. Specifically, a tuner amplifier can be mentioned.

That is, the optical signal propagating to the waveguide mechanism of such an optical functional element includes optical signals of a plurality of wavelengths that are independently modulated.

Further, in the present invention, the optical signal can be converted into the radiation mode light and output.

Further, the radiation mode output can be amplified with respect to the signal intensity input to the waveguide mechanism.

Further, the radiation mode output can be divided and outputted to a plurality of output ports.

Further, the optical signals of the plurality of wavelengths can be selectively tuned according to the wavelength and taken out as a radiation mode output.

The optical functional device of the present invention described above can be configured to perform a laser oscillation operation in the waveguide mechanism.

In this case, the laser oscillation characteristics can be improved by providing the second reflection mechanism at at least one end of the waveguide mechanism.

Further, such a laser output may be taken out from at least one end of the waveguide mechanism.

Alternatively, the laser output may be taken out from the resonator formed by the first reflection mechanism as the radiation mode light.

Further, the resonator formed by the first reflection mechanism may be configured to perform a laser oscillation operation.

Further, the input of the light from the outside or the output of the light to the outside is performed by comparing the waveguide mode from at least one end face of the first waveguide mechanism and the radiation mode from the first waveguide mechanism. The method is characterized in that the operation is performed in any one of the modes or both the waveguide mode and the radiation mode.

Further, a light collecting function for optically coupling to another optical element is provided in the external light input section or the external light output section. Further, at least one of the waveguide mechanism and the amplification mechanism includes a medium that generates a gain by optical excitation.

More specifically, the medium for generating a gain by the light excitation is a medium containing at least one of erbium (Er), Pr (praseodymium), and other rare earth elements. .

Further, a light-transmitting electrode for supplying current or applying an electric field is provided between the waveguide mechanism and the amplification mechanism.

Further, the present invention is characterized in that the real part or the imaginary part of the refractive index of the waveguide mechanism can be changed by applying an electric field.

On the other hand, by providing a plurality of resonators formed by the first reflection mechanism along the waveguide mechanism, pumping in the waveguide mechanism can be changed along the waveguide direction. This allows tuning of the oscillation wavelength. Further, the light intensity in the waveguide direction becomes flat, and it is possible to compensate for oscillation instability depending on non-uniformity such as spatial hole burning.

Further, the plurality of resonators may be controlled and modulated independently.

The oscillation wavelengths of the laser beams of the plurality of resonators may be different from each other.

Alternatively, the oscillation wavelengths of the laser beams of the plurality of resonators have different wavelengths depending on the reflection characteristics of the first reflection mechanism, the wavelength characteristics of the phase control mechanism or the amplification mechanism, or the control mechanism thereof. Control may be performed as follows.

The output of the laser beam from the resonator formed by the first reflection mechanism may be taken out from at least one end of the first waveguide mechanism.

Alternatively, the output of laser light from a resonator formed by the first reflection mechanism may be taken out from at least one of the reflectors of the resonator as the radiation mode light.

On the other hand, in the optical function device described above,
A light receiving mechanism for output light may be further provided.

Further, at least one of the amplification mechanism, the phase control mechanism and the reflection mechanism may constitute a waveguide mechanism independent of the waveguide mechanism. A specific example is an active DBR structure.

Further, such an independent waveguide mechanism can be formed perpendicular to the first waveguide mechanism.

Alternatively, such an independent waveguide mechanism is formed in parallel with the first waveguide mechanism, has a diffraction grating, and is provided with the first waveguide structure and the diffraction grating interposed therebetween. May be optically coupled.

The optical function device described above can be formed as a device in which at least two or more of the above mechanisms are monolithically integrated.

Further, such a monolithic integration state can be a state of being stacked in a direction perpendicular to the substrate surface.

Further, of the plurality of mechanisms stacked in the direction perpendicular to the substrate surface, a portion having a pn junction may have a lateral junction stripe (TJS) structure.

Further, an insulating or semi-insulating layer may be inserted between the plurality of lateral junction stripe structures.

On the other hand, an optical communication device according to the present invention includes any one of the above-described optical functional elements.

[0055]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a hologram capable of generating radiation mode light, for example, in a waveguide having a second-order or higher diffraction grating, a part of the guided light is radiated as radiation mode light in a direction perpendicular to the waveguide direction. In the present invention, the radiation mode light is amplified by another amplification mechanism, and is returned to the waveguide again using the reflection mechanism. Since the radiation mode light is emitted on both sides of the waveguide, it is desirable to provide a reflection mechanism on both sides. The present invention
It includes many applied inventions based on this unique resonator configuration. One of them is an amplifier. The present invention further includes an optical modulator, a laser oscillator, and an optical communication device using the coupler.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a conceptual diagram showing an optical functional device according to the first embodiment of the present invention. The basic principle of the optical functional device of the present invention will be described with reference to FIG. First, the optical functional device according to the present invention has a waveguide mechanism for guiding light.
In the illustrated example, the optical waveguide 1 is used as a waveguide mechanism.
Is provided. On the optical waveguide 1, a second-order diffraction grating 2
Are formed. The waveguide 1 may be an optical fiber, a general dielectric waveguide, or a semiconductor waveguide. For example,
An InGaAsP / InP waveguide can be used.
This is a laminated structure (slab waveguide: slab waveguide) in which InGaAsP quaternary mixed crystal having a high refractive index is used as the core of the waveguide, and InP having a low refractive index is sandwiched from above and below by cladding. This is a one-dimensional cross section, but it may also be a two-dimensional buried waveguide embedded with InP from a lateral direction.

As shown in FIG. 1, a part of the light guided in the waveguide 1 having the secondary diffraction grating 2 is radiated in both the vertical and vertical directions substantially perpendicular to the waveguide direction. This is so-called radiation mode light.

In the present invention, the configuration is such that this radiation mode light is passed through the amplification mechanism 3. This amplification mechanism 3
It has the function of amplifying light. The amplification mechanism 3 is an EDFA
(Erbium Doped Fiber Amplifier), SOA (Semicond
uctor Optical Amplifier) or an optically pumped gain medium. For example, when InG
It can be a pn junction of an aAsP / InP laminated structure.

However, it is desirable that the amplifying mechanism 3 is arranged at a sufficient distance so as not to directly hinder the waveguide mode of the waveguide 1. This is in accordance with the gist of the present invention in that a resonator structure is formed for a light wave converted from a waveguide mode to a radiation mode.

At the end of the amplification mechanism 3, a reflection mechanism 4 having a higher reflectance is arranged. This reflection mechanism 4
It has a function of reflecting the radiation mode light with a high reflectance, and for example, can be constituted by a dielectric multilayer film. The radiation mode light reflected by the reflection mechanism 4 is amplified again by the amplification mechanism 3 and returns to the waveguide 1 via the diffraction grating 2. By repeating such amplification / reflection / amplification cycles, a unique resonator structure is realized. A more specific configuration example of the optical functional element will be described later in detail.

Next, a second embodiment of the present invention will be described. FIG. 2 is a conceptual diagram illustrating an optical functional device according to a second embodiment of the present invention. That is, in the element shown in the figure, a stronger resonator mechanism is realized by providing the above-described resonator structure both above and below the waveguide 1. That is, each of the radiation mode lights emitted upward and downward in the waveguide 1 repeats the cycle of amplification / reflection / amplification.

A feature of the radiation mode is that a very sharp beam can be output over the entire area where the diffraction grating exists. Therefore, the radiation mode light has the flexibility to configure various optical functions along the waveguide, unlike the output of the end face of the waveguide regarded as a point light source. For example, there is an input / output light collecting function for coupling with another optical element. Specifically, there are a lens function, another hologram, an optical isolator, and the like.

Next, a third embodiment of the present invention will be described. FIG. 3 is a conceptual diagram illustrating an optical functional device according to a third embodiment of the present invention. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. In the present embodiment, a phase control mechanism 5 is added to the configuration of the above-described second embodiment. The phase control mechanism 5 has a function of controlling the phase of the light, and adjusts the phase of the reflected light so that the reflected light from the reflection mechanism 4 can be efficiently coupled to the waveguide 1 via the diffraction grating 2. is there. Thereby, the coupling efficiency of the reflected light to the waveguide 1 can be improved, and resonance can be performed with higher efficiency.

As a specific example of the phase control mechanism 5, an InGaAsP / InP slab type waveguide structure having a pn junction can be given. The p of such a waveguide
When a current is applied to the n-junction or an electric field is applied with a reverse bias, the refractive index changes and the phase of light can be controlled. Further, the phase control mechanism 5 may be provided between the amplification mechanism 3 and the reflection mechanism 4 or may be provided between the waveguide 1 and the amplification mechanism 3.
May be provided in between. The amplification mechanism 3 can change the carrier density and the refractive index by energization. An application in which the phase is canceled by the phase control mechanism 5 is also conceivable.

The basic structure of the optical functional device of the present invention has been described as the first to third embodiments. Next, the theoretical background of the resonator structure according to the present invention will be described. First, it is assumed that a waveguide having a second-order or higher diffraction grating oscillates by distributed feedback. In the analysis method proposed by the inventor, the amplitude of the radiation mode in the diffraction grating is approximately expressed by the following equation.

[0067]

(Equation 1) Here, it is assumed that the diffraction grating exists from x = 0 to x = g of the coordinates of the waveguide. A (x) in equation (1) represents the amplitude of a radiation mode radiated downward from the lower end (x = 0) of the diffraction grating area, and b (x) in equation (2) is the upper end (x = G) x of the radiation mode radiated upward from
Represents the amplitude at. T (x) is the Fourier coefficient of the diffraction grating and the field of the guided mode (field:
It is a function determined by the field.

The constants C _a and C _b are constants determined by boundary conditions. This constant is determined under the boundary condition that the radiation modes emitted above and below the waveguide are respectively reflected by the reflection mechanism. The reflectance above the waveguide is r _g , and the amplitude reflectance below the waveguide is r ₀ . Note that these reflectivities include the phase. The effect of the layer structure from the radiation mode being emitted from the diffraction grating to the reflection mechanism is also included in this reflectivity, and is determined on the assumption that the reflection mechanism is present at the boundary of the diffraction grating region. That is, a _n (g) = r _g b _n (g), b _n (0) = r ₀ b
_n (0).

Then, the constants C _a and C _b can be expressed by the following equations, respectively.

[0070]

(Equation 2) However, the following equation was defined.

[0071]

(Equation 3) Here, what is important is the denominator of Expression (3). That is,

[0072]

(Equation 4) If the following relationship holds, the denominator of equation (3) becomes zero,
The constants C _a and C _b are infinite. That is, equation (1),
As can be seen from (2), oscillation occurs as a “radiation mode resonator”. That is, it can be seen that oscillation occurs when the reflectance is large, the gain is high, and the phase condition is satisfied.

Further, when viewed from the waveguide side, the radiation mode, which has been a loss in the past, is amplified and returned in the present invention, so that it becomes a gain. Therefore, the radiation mode loss in the coupled wave equation used for the analysis of the DFB laser is replaced by the gain term. Even if the emission mode resonator does not reach the oscillation condition, the DFB laser can oscillate at a low threshold.

It is easy to understand from the description that the claims of the present application claim three elements for the radiation mode: an amplification mechanism, a reflection mechanism, and a phase control mechanism.

The configurations of the first to third embodiments described above are the basis of the present invention. However, in the present invention,
Elements such as the above-described amplification mechanism, reflection mechanism, and phase control mechanism need not exist independently of each other. For example, as in a fourth embodiment described below, two or more mechanisms may be commonly included in one component.

FIG. 4 is a conceptual diagram illustrating the configuration of an optical functional device according to a fourth embodiment of the present invention. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. In the optical function device shown in FIG. 1, there is no medium 3 having a gain. Instead, an active layer 6 having a gain is provided near the waveguide 1. The reflection mechanism 4 'also has a gain. That is, the active layer 6 and the reflection mechanism 4 'function as an amplification mechanism.

As an example in which the reflection mechanism has a gain, a DBR (Distributed Bragg Reflector) mirror made of a semiconductor multilayer film stacked in a plane direction is provided with a pn.
A junction may be formed to provide gain by current injection, or another waveguide may be provided perpendicular to waveguide 1,
A DBR mirror may be provided therein.

Next, a fifth embodiment of the present invention will be described.

FIG. 5 is a conceptual diagram showing an optical functional device according to a fifth embodiment of the present invention. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. In the example shown in the figure, the second-order or higher diffraction grating 2 has a phase shift 20, that is, a phase discontinuity. The phase shift 20 is effective for controlling the intensity distribution of the radiation mode in the direction parallel to the waveguide. That is, when a radiation mode is generated from the waveguide, the waveguide allows two waves having opposite traveling directions. The intensity distribution in the axial direction of the radiation mode, that is, in the waveguide direction, is greatly affected by the increase or decrease of the intensity due to the interference between the respective radiation modes generated by the two waveguide modes. The state of this interference changes due to the phase shift. Therefore, providing an appropriate phase shift has a great merit. In addition, since the phase shift affects the axial strength of the waveguide mode itself, it can be an important component of the present invention.

That is, when there is no phase shift, a longitudinal mode having a small radiation mode intensity oscillates at the center of the waveguide.
On the other hand, for example, when the reflection at both end surfaces of the waveguide is suppressed low, a phase shift equivalent to λ / 4 is provided at the center of the waveguide, and this waveguide is oscillated by DFB (distributed feedback), the phase shift At the position, a longitudinal mode in which the intensity of the waveguide mode and the radiation mode is large oscillates.

In other words, the intensity distribution in the axial direction of the radiation mode that is fed back with the gain matches the intensity of the waveguide mode.
Because of spatially strong synchronization at the phase shift position, optical feedback,
That is, the effect that the efficiency of the resonator becomes extremely large is obtained.

Incidentally, instead of such a phase shift,
The same effect can be obtained even if a structure that changes the effective refractive index of the waveguide is adopted. That is, even if the period of the diffraction grating is uniform, it can be replaced by providing an effective phase shift region (not shown) in which the width, thickness, or refractive index of the waveguide structure is changed. Further, it is desirable that the phase shift has a phase shift amount in a range from an integral multiple of the wavelength λ in the waveguide to １ ／ to ／. The aforementioned ４ corresponds to the center value of this range.

Next, a sixth embodiment of the present invention will be described. FIG. 6 is a conceptual diagram illustrating an optical functional device according to a sixth embodiment of the present invention. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. In the present embodiment, a so-called blaze angle (bl) in which the cross-sectional shape of the diffraction grating 2 is asymmetric.
aze angle). In a diffraction grating having a symmetrical cross-sectional shape without blaze, a radiation mode generated by a guided mode traveling in a predetermined direction is radiated almost equally in two vertical directions. However, if there is a blaze, selectivity can be given to the radiation mode radiated up and down. For example, in FIG. 6, a light wave passing through the waveguide from left to right has a large proportion radiated upward in the drawing, and has a large proportion radiated downward in the opposite direction.

The following merits can be obtained by introducing such a blaze angle. That is, when the signal light is always propagating in one direction with respect to the waveguide, the radiation mode radiated to any one of the upper and lower sides of the waveguide can be increased depending on the angle of the blaze. And
If the one-side mechanism is enhanced by increasing the reflectance on the large side or increasing the gain of the amplification mechanism, the function can be efficiently enhanced. If the effect of amplifying a signal propagating in the opposite direction is reduced, the function of an optical isolator or a directional coupler can be provided.

Next, a seventh embodiment of the present invention will be described. The optical function device of the present embodiment can be described using the configurations illustrated in FIGS. That is,
In the present embodiment, the modulation of the waveguide mechanism, the amplification mechanism, and the reflection mechanism is independently controlled. These are basic requirements for an optical functional device that handles optical signals, together with the phase control mechanism described in the third embodiment. For example, by controlling the modulation of the amplification mechanism, the condition of the above-described expression (5) is satisfied, and the oscillation of the resonator perpendicular to the waveguide can be controlled by current injection. The modulation of other parameters, that is, the parameters of the waveguide mechanism and the reflection mechanism, can be similarly controlled.

Next, an eighth embodiment of the present invention will be described. FIG. 7 is a conceptual diagram illustrating an optical functional device according to the present embodiment. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. In the present embodiment, another resonance structure using the radiation mode is formed along the waveguide. Forming along the waveguide means that the entire length of the long waveguide can be utilized. Therefore, it is possible to make the resonator structure change along the waveguide. Also, a number of resonator structures can be formed along the waveguide.

In the example shown in FIG. 7, the waveguide structure 1
The period of the diffraction grating 2 changes along the waveguide. In this example, the period of the diffraction grating is 3 of Λ1, Λ2, and Λ3.
Kind. Further, a reflection mechanism 4, a phase modulation mechanism 5, and an amplification mechanism 3 are provided corresponding to the diffraction grating of each period.

The operation of the optical function device will be described as follows. In other words, the waveguide 1 is excited to generate spontaneous emission light. The diffraction grating period in it Λ
The radiation modes of the wavelength components radiated vertically corresponding to 1, Λ2 and Λ3 are amplified in the respective radiation mode resonators. As for the degree of amplification, a specific wavelength can be freely amplified by independently controlling gain, reflectance, phase and the like. The reflection mechanism itself can also enhance the wavelength selectivity by employing a configuration such as a DBR. Also,
It is also possible to match the peak of the gain spectrum to that particular wavelength. If the amplification is strong, it can be oscillated. Such amplified light can be extracted from each resonator. Further, it can be returned to the waveguide 1 and taken out from the end face. Further, it is also possible to take out a signal obtained by modulating a specific wavelength in each resonator.

Since such a structure also has functions of a multiplexer and a demultiplexer, the optical circuit can be laid out in a small space. Therefore, it is suitable for monolithic integration. In the example of FIG. 7, the waveguide mechanism and other mechanisms can be monolithically integrated on a substrate such as InP. However, besides, for example, the waveguide may be a fiber and the diffraction grating may be a fiber grating.

Further, instead of changing the period of the diffraction grating, a wavelength selecting function can be provided by locally changing the effective refractive index of the waveguide 1. Others
An application example in which the period of the diffraction grating is not changed stepwise but continuously changed is also conceivable.

Next, a ninth embodiment of the present invention will be described.

FIG. 8 is a conceptual diagram showing an optical functional device according to a ninth embodiment of the present invention. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. The configuration is similar to that of the above-described eighth embodiment. The main difference is the way of application. That is, in the present embodiment, the waveguide 1 is positioned as a transmission line through which signals, particularly a plurality of signals having different wavelengths, propagate. With the same configuration as in the eighth embodiment, it is possible to realize a function of tuning (tuning) the signal and separately amplifying and extracting the signal. That is, the present embodiment corresponds to a tuner amplifier.

At the same time, the transmission system of this embodiment is also a ring network. That is, a signal input from the left end of the waveguide is also output from the right end and detected at another terminal. In this case, the amplification function of the radiation mode resonator structure also serves as a repeater, preventing signal attenuation.

The operation of the device of this embodiment is the same as that of the eighth embodiment.
It is based on the concept of the embodiment. That is, the radiation modes vertically radiated from the diffraction gratings having different periods are amplified by a resonator having wavelength selectivity, and the output is detected. In FIG. 8, each resonator is regarded as an output port, and signals having different wavelengths are output downward for each port and received by a detector (not shown).

When the wavelength interval determined by the period of the diffraction grating (the wavelength interval between # 1, # 2, and # 3 in the example of FIG. 8) is wide, except for the diffraction grating portion having a period corresponding to each wavelength, The radiation is emitted in a direction deviated from the direction perpendicular to the waveguide. Therefore, tuning is performed only by the arrangement of the resonators. Tuning is also performed by modulating the refractive index of the waveguide.

When the wavelength interval is small, tuning can be performed by modulation by the phase control mechanism 5 or by changing the refractive index of the DBR reflection mechanism.

Next, a tenth embodiment of the present invention will be described.

FIG. 9 is a conceptual diagram showing the optical functional device of the present embodiment. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. The present embodiment is centered on an optical functional element having a function of oscillating a laser. A remarkable feature of the present invention is that a radiation mode resonator is provided in addition to the waveguide resonator of the ordinary waveguide laser. Therefore, a variation occurs in which one is the main resonator and which is the auxiliary resonator.
Of course, there is also a combination in which both are oscillated. There is also a variation where output is taken from.

FIG. 9 exemplifies a case where the waveguide mechanism 1 can generate optical feedback only by the diffraction grating, but is provided with a reflecting structure 30 on both end surfaces for further enhancing the feedback.

When the waveguide mechanism is used as the main resonator as in the conventional laser, the radiation mode resonator can be interpreted as an optical pumping mechanism for the main resonator. Since this pumping mechanism can be densely arranged along the waveguide 1, very efficient excitation can be achieved. In a conventional semiconductor laser in which a current is injected only into a waveguide, the current density in a narrow waveguide becomes high, and there is a problem that the active layer 6 is deteriorated and local heat is generated. In contrast, according to the invention, the injection of the current is distributed towards the auxiliary resonator,
The effect of heat can be reduced, and the reliability can be improved. Another advantage of the present invention is that both current excitation and optical excitation can be balanced with respect to the main resonator.

The optical output can be implemented both in the conventional case where it is extracted from the end face (output 100) and in the case where it is extracted along the waveguide as a radiation mode amplified from the radiation mode resonator (output 200). Either convenient output mode can be selected.

When the main resonator is a radiation mode resonator, the waveguide mechanism 1 can be considered as an optical pumping mechanism. As in the above-described example, both the case where the optical output is extracted from the end face (output 100) and the case where the optical output is extracted from the radiation mode resonator along the waveguide (output 200) can be implemented. Of course, any convenient output form can be selected.

The present embodiment also has a light receiving mechanism 40 as a mechanism commonly added to the present invention. in this case,
The output light is monitored by the light receiving mechanism 40,
The output of the laser can be controlled using an external circuit (not shown). For example, APC (Automatic power control) for keeping the output of the laser constant can be applied. The optically pumped waveguide mechanism 1 can be provided with a medium that cannot be current-excited as a material, in particular, a medium that has gain only by optical excitation. For example, it is a silica-based waveguide doped with Er (erbium) or Pr (praseodymium). These are similar to a so-called fiber amplifier. The resonator in the radiation mode along the waveguide 1 has a strong optical pumping effect on the waveguide amplifier. If the purpose is only for excitation, the reflectivity for the radiation mode can be almost 100% and the output 200 can be neglected.

The light excitation and the current excitation can be selectively used on the opposite side, ie, on the radiation mode resonator side. However, in general, the above example in which excitation is performed along a long waveguide is more efficient. In addition, a passive (pa
The use of a ssive) material also provides significant manufacturing advantages. That is, this is a case where it is difficult to form a waveguide having an appropriate difference in refractive index from a semiconductor having a pn junction. At this time, the waveguide may be formed of a material other than a semiconductor.
This is a configuration having a quartz (SiO ₂ ) cladding and a SiN core, for example.

FIG. 10 is a conceptual diagram illustrating the cross-sectional structure of a device employing a quartz cladding. That is, FIG. 2A is a cross-sectional view along the central axis of the waveguide.
FIG. 2B is a cross-sectional view cut perpendicularly to the waveguide.

The structure will be described according to the manufacturing process.
It is as follows. First, the active layer 3 having a gain by a pn junction with the DBR reflector 4 'is grown on the semiconductor substrate 50.
The troublesome crystal growth alone is sufficient, and the number of times of growth can be reduced. The electrode is a transparent electrode 55 such as ITO (indium tin oxide). On top of this, quartz (Si
O ₂ ) A waveguide structure 1 comprising a clad 1b and a SiN core 1a is formed. A secondary diffraction grating 2 is formed in the SIN waveguide core 1a. On this waveguide structure 1, a dielectric high reflection multilayer film 4 'made of SiO ₂ and Si (silicon) is further formed. An electrode 70 is formed on the back surface of the substrate 50. A wire 60 is bonded to the transparent electrode 55. The current injected through the transparent electrode 55 is applied to the active layer 3 under the waveguide structure 1 by the current block region 53 as shown by an arrow in FIG.
Flows into.

According to this modification, the current-carrying region and the waveguide region can be separated by completely different material systems, so that the fabrication is easy. For example, in addition to the above-described combination of SiO ₂ clad / SiN core, the waveguide region may be an optical fiber on which a diffraction grating is formed, or a diffraction grating is formed on a transparent electrode such as ITO. A clad made of a material such as SiO ₂ may be laminated.

As described above, if the waveguide region is made of a material different from that of the current-carrying region, the waveguide portion is formed so as not to damage the expensive semiconductor growth wafer even if the fabrication of the waveguide portion fails. The process of forming can be redone.
In addition, since a waveguide can be formed with a refractive index smaller than that of a semiconductor, the size thereof can be about twice as large, so that there is an advantage that processing is easy.

Further, since the temperature change of the refractive index of the diffraction grating 2 and the waveguide portion 1 which determine the oscillation wavelength is smaller than that of the semiconductor material, a laser whose wavelength is stable with respect to temperature can be realized.
This is WDM (wavelength division mult) in optical communication.
Suitable for light sources for iplexing. In addition, since the waveguide section 1 is similar to a silica-based fiber, coupling with the fiber is facilitated.

As described above, it is not necessary to process the semiconductor on the waveguide in the gain region. Since there is no need to provide a light-mode bleeding area outside the active layer stripe, the manufacture of the semiconductor portion is greatly facilitated.

On the other hand, a great effect can be obtained even if the waveguide is formed of a passive semiconductor material. If the waveguide is passive, the waveguide itself is not affected by the carrier density. Therefore, it is possible to prevent a phenomenon called "hole burning" in which the refractive index is nonuniform due to the spatial nonuniformity of the carrier density and the horizontal mode and the vertical mode are unstable. therefore,
The mode is stable even at high output, and the current-light output characteristics do not have a bending called "kink".

Further, there is a method of operating the waveguide 1 with a reverse bias. FIG. 11 is a conceptual diagram illustrating a cross-sectional structure of an element in which a waveguide is operated with a reverse bias. In the figure, the same parts as those in the above-described specific examples are denoted by the same reference numerals, and detailed description is omitted.

In this device, the layer between the waveguide structure 1 and the gain region 3 is formed of an n-type InP ground.
So that the upper and lower layers are p layers. Here, when the waveguide 1a (core) is formed of a material having a crystal composition such that the real part of the refractive index changes with an electric field, the oscillation wavelength can be adjusted by the electric field. That is, a tunable laser having a wide tuning range can be realized.

Alternatively, if the waveguide 1a (core) is formed of a material having a crystal composition in which the imaginary part of the refractive index changes with an electric field, the loss changes with the electric field. This is the same operation as the electroabsorption type external modulator. The change due to the electric field can be used for modulating the output light. In this case, unlike the direct modulation by the electric current, the modulation is by the electric field of the optical loss. Compared to the case where the injected carrier density in the forward direction is modulated, in the case of this specific example, a clear output waveform with high speed and little influence of relaxation oscillation can be obtained. This corresponds to obtaining a so-called "eye open state" when observing the output waveform, and enables high-speed optical transmission with a very low bit error rate. Further, the laser and the modulator can be integrated.

FIG. 12 is a conceptual diagram illustrating a cross-sectional structure of an optical function element in which a laser and an optical modulator are integrated. In a so-called direct modulation method in which a current injected into a laser is changed, chirp also occurs due to a change in refractive index. On the other hand, in this specific example, by separating and integrating the EAM, which is an electro-absorption type modulator, it is possible to achieve higher speed and more stable optical transmission.

That is, the core portion 1a of the waveguide 1 has a crystal composition such that the imaginary part of the refractive index changes due to an electric field. For example, InGaAsP is used. Then, the loss of light changes by the application of the electric field. This is the same operation as the electroabsorption type external modulator. The change due to this electric field can be used for light modulation.

In addition to the main structural part of the present invention which functions as a laser, an extended part of the waveguide with a diffraction grating (in this part, the diffraction grating is removed to eliminate the laser function) is provided by an electroabsorption type external modulator ( EAM: Electro-Absorption M
odulator). In this case, it can be formed from the active (gain) region to the waveguide by a single crystal growth. The waveguide of the present invention is separated from the active region and the DBR and can be prevented from affecting the propagation of the guided mode, and thus can be grown in a single operation. In the EAM portion, no current is injected into the active region and no excitation occurs. If the active region is not excited, the absorptance increases, but in the present invention, since the waveguide 1 is provided separately, light can propagate and modulate through the waveguide 1.

The waveguide portion of the active region having the diffraction grating is:
Tunable within a range that does not significantly increase absorption
It can also be a type of laser.

The EAM is different from the direct modulation of a laser by an electric current, in which an optical loss is modulated by an electric field. Compared with the modulation of the injected carrier density in the forward direction, there is an advantage that a clear output waveform with high speed and little influence of relaxation oscillation can be obtained. Next, an eleventh embodiment of the present invention will be described. FIG. 13 is a conceptual diagram illustrating an optical functional device according to the present embodiment. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. In the present embodiment, a plurality of radiation mode resonators are arranged along the long waveguide 1, and control modulation is performed independently of each other. With this configuration, when the waveguide 1 is the main oscillator, the pumping can be changed in the waveguide axis direction. This allows tuning of the oscillation wavelength. Further, the light intensity in the waveguide axis direction becomes flat, and it is possible to compensate for oscillation instability depending on non-uniformity such as spatial hole burning.

When a plurality of radiation mode resonators are used as main oscillators, each of them can be independently modulated. Furthermore, wavelength multiplexing communication (WDM: wavelength communication) for controlling each oscillation wavelength to be different so as to output to the waveguide 1 is performed.
It can also be applied to light sources for ngth division multiplexing.

The tuner amplifier according to the ninth embodiment is an optical functional element that receives an optical signal by demultiplexing it. In the present embodiment, the radiation mode resonator is used as a wavelength division multiplexing laser oscillator. An optical functional element that multiplexes and transmits to the waveguide can be obtained. Since the transmitter of the present embodiment and the receiver of the ninth embodiment have similar configurations, they are also excellent in productivity.

Next, a twelfth embodiment of the present invention will be described.

FIG. 14 is a conceptual diagram showing an optical functional device according to the present embodiment. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. The present embodiment is a modification of the radiation mode resonator, and the radiation mode resonator itself has a waveguide function. That is, in the optical function device shown in FIG. 14, a resonator for amplifying a radiation mode is provided with a waveguide type active DB.
6 is a configuration example realized by an R structure 7. Here, the “active DBR” is a distributed reflector having gain and wavelength selectivity. In the present embodiment, an amplification mechanism,
The reflection mechanism and the phase control mechanism are put together in the active DBR waveguide 7.

This has a configuration partially similar to a normal DFB laser. That is, if the waveguide has a diffraction grating, has an active layer, and a gain can be obtained by supplying a current, it has an amplifying function. If the refractive index is changed by a reverse bias electric field, a phase control function can be obtained. Of course,
Needless to say, it also has a reflection function of reflecting and returning an input by the diffraction grating.

The radiation mode is formed so as to be guided to the DBR waveguide 7 via the tapered region 8 for receiving the radiation mode. The direction of the DBR waveguide 7 is made perpendicular to the waveguide 1 in consideration of the direction of the radiation mode.

Next, a thirteenth embodiment of the present invention will be described.

FIG. 15 is a conceptual diagram showing an optical functional device according to the present embodiment. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. This embodiment is related to the twelfth embodiment described above. That is, the upper side of the resonator that amplifies the radiation mode is configured as a waveguide 1 ′ parallel to the original waveguide 1. An active region 6 'is formed in the waveguide 1' and has a gain, that is, an amplifying effect. The reflection film 30 'is formed on the end face. The coupling of the radiation mode to the waveguide 1 ′ is performed by a diffraction grating 2 ′ similar to the secondary diffraction grating 2 formed in the waveguide 1. From another point of view, the present embodiment can be said to have a plurality of structures of the waveguide 1 and to be coupled by diffraction gratings. Therefore, as a modification of the present embodiment, a vertical resonator (not shown) may be further provided above the waveguide 1 ′.

Next, a fourteenth embodiment of the present invention will be described.

FIG. 16 is a partially cutaway perspective view showing an optical functional device according to the present embodiment. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. The configuration of the optical functional device of the present embodiment,
The following is a description along the manufacturing process.

First, on the same n-type InP substrate 501,
After growing the same n-type InP buffer layer (not shown),
Active layer and waveguide layer made of InGaAsP (1 + 6)
Grow. This is patterned to form a second-order diffraction grating 2 on the side surface. At this time, the gain region 3 is also formed as the remaining portion.

On top of this, a p-type InP cladding layer 502,
A p-type InGaAsP contact layer 503 is grown. Next, in order to excite the active waveguide (1 + 6) and the gain region 3 independently, a proton irradiation region 504 for isolation is formed. Further, the p-side electrodes 505, 50
6, and an n-side electrode 507 is formed on the back surface of the substrate. Finally, a high reflection film 4 is deposited on the cleavage plane outside the gain region 3.

As described above, the configuration of the present invention can be monolithically integrated on the InP substrate. This example is an example in which functions are integrated in a direction horizontal to the surface of the substrate. Also, the illustrated example is a simple basic element, but it is also possible to integrate a plurality of elements such as an array.

Next, a fifteenth embodiment of the present invention will be described.

FIG. 17 is a schematic perspective view showing an optical functional device according to the present embodiment. Also in this figure, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description is omitted. The example shown in FIG. 17 is GaAlAs / G
This is an example in which an aAs-based material is used, and the configuration will be described below along the manufacturing process.

First, on a semi-insulating GaAs substrate 601,
A lower high-reflection multilayer film 4 is grown. The multilayer film 4 can have, for example, a multilayer structure of an AlAs layer and a GaAs layer. Further, with respect to the multilayer film 4 thus grown, the AlAs layer may be changed to an Al oxide by a selective oxidation method to further increase the reflectance. On this, a GaAs amplification layer 3 having a gain is grown,
Further, an n-type AlAs layer 602, GaAlAs (Al
(Composition ratio: 0.3) The cladding layer 603 is grown. After successively growing the active layer 6, GaAlAs (Al composition ratio:
The waveguide layer 1 of 0.15) is grown. After being taken out of the growth furnace, a second-order diffraction grating 2 is formed. next,
The GaAlAs cladding layer 603 is grown again in the crystal growth step. Further, the GaAs contact layer 60 is continuously formed.
Grow 4.

A pn junction is formed by a diffusion region 610 in which Zn (zinc) is diffused. This is a so-called transverse junction strip (TJS).
e) The structure. A pn junction can be formed simultaneously with the layer structure of the amplification mechanism 3 and the layer structure of the active layer 6 that are stacked and integrated. The TJS structure has a feature that light is confined near the junction and guided. Further, a dielectric multilayer film is formed as the high reflection film 5 on the upper side.

In this manner, an integrated device in which each mechanism is stacked in a direction perpendicular to the substrate surface can be obtained. In addition, a part of the AlAs layer 602 is changed to the Al oxide film 650 by the selective oxidation method using water vapor from the lateral direction, and the active layer 6 and the gain layer 3 are changed.
And an effect of current constriction can be provided.

Further, a p-side electrode 505, an n-side electrode (for a waveguide) 507, and an n-side electrode (for an amplification layer) 508 are formed to complete an optical functional device.

The optical functional device of this embodiment can be said to be a surface-type vertical integrated device. As in the fourteenth embodiment, the present invention can be applied to an array having a plurality of elements.

Next, a sixteenth embodiment of the present invention will be described. FIG. 18 is a conceptual diagram illustrating the optical communication device according to the embodiment. That is, the optical communication device shown in the figure applies the optical functional element 700 according to the present invention. Around the optical function element 700, an electronic circuit unit 900 such as a drive circuit of a laser diode (LD), a circuit for measuring a photocurrent from a photo diode (PD), an APC circuit, and a signal generator is connected. The optical signal generated in the optical function element is transmitted through the optical fiber 800. Of course, it may be transmitted by spatial transmission without using a fiber.

According to the present invention, since various functions are integrated, the size of the transmission / reception device can be extremely reduced. In addition, since the assembly is simplified when manufacturing the transmission / reception device, the cost can be significantly reduced. Furthermore, connection with an optical fiber becomes easy. Further, since the waveguide having a small temperature change can be separated from the gain region having a large temperature change, the wavelength stability can be maintained.

The embodiments of the present invention have been described with reference to the examples. However, the present invention is not limited to these specific examples.

For example, in the above specific example, In
Although the GaAsP / InP system and the GaAlAs / GaAs system have been described, the present invention can be similarly applied using various material systems other than these. As such a material system, for example, an InGaAlP system, BInG
various Al-based III-V compound semiconductors, such as Zn
Group II-IV compound semiconductors such as Se-based and ZnS-based, SiC
And other materials such as Group IV semiconductors.

Further, the specific configurations of the waveguide mechanism, the amplification mechanism, the reflection mechanism, the phase control mechanism, and the like used in the present invention are the same as those of the above-described specific example using the configuration appropriately selected by those skilled in the art. The effect can be obtained.

Further, those skilled in the art can appropriately determine the number of these mechanisms and the specific arrangement relation to obtain the same effect.

That is, the present invention can be variously applied or extended without departing from the gist thereof.

[0147]

According to the present invention, a novel optical device having various functions can be realized by applying a new concept of a radiation mode resonator structure along various waveguide structures.

In the above description, the number of specific examples is large, and the effects are described individually in each specific example.
Here, general effects are mentioned.

According to the present invention, since elements such as the amplification mechanism and the reflection mechanism are arranged along the waveguide, efficient interaction with the waveguide is possible. One example is efficient light excitation. In addition, by providing them along the waveguide, efficient arrangement is possible, and a large area is not required. This also lends itself to monolithic integration. In addition, since the diffraction grating itself has the wavelength selectivity and the function of the diffraction grating coupler, the functions of a demultiplexer and a multiplexer are realized, and when used as an optical device for wavelength multiplexing, a compact and low-cost optical device is used. A functional element can be realized.

Further, by using a low-cost, high-performance optical functional element as described above, a high-performance optical communication device can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating an optical functional device according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram illustrating an optical functional device according to a second embodiment of the present invention.

FIG. 3 is a conceptual diagram illustrating an optical functional device according to a third embodiment of the present invention.

FIG. 4 is a conceptual diagram illustrating a configuration of an optical functional device according to a fourth embodiment of the present invention.

FIG. 5 is a conceptual diagram illustrating an optical functional device according to a fifth embodiment of the present invention.

FIG. 6 is a conceptual diagram illustrating an optical functional device according to a sixth embodiment of the present invention.

FIG. 7 is a conceptual diagram illustrating an optical functional device according to a seventh embodiment of the present invention.

FIG. 8 is a conceptual diagram illustrating an optical functional device according to a ninth embodiment of the present invention.

FIG. 9 is a conceptual diagram illustrating an optical functional device according to a tenth embodiment of the present invention.

FIG. 10 is a conceptual diagram illustrating a cross-sectional structure of a device employing a quartz cladding.

FIG. 11 is a conceptual diagram illustrating a cross-sectional structure of an element in which a waveguide is operated with a reverse bias.

FIG. 12 is a conceptual diagram illustrating a cross-sectional structure of an element in which a laser and an optical modulator are integrated.

FIG. 13 is a conceptual diagram illustrating an optical functional device according to an eleventh embodiment of the present invention.

FIG. 14 is a conceptual diagram illustrating an optical functional device according to a twelfth embodiment of the present invention.

FIG. 15 is a conceptual diagram illustrating an optical functional device according to a thirteenth embodiment of the present invention.

FIG. 16 is a partially cut perspective view showing an optical functional device according to a fourteenth embodiment of the present invention.

FIG. 17 is a schematic perspective view illustrating an optical function element according to a fifteenth embodiment of the present invention.

FIG. 18 is a conceptual diagram illustrating an optical communication device according to an embodiment of the present invention.

[Explanation of symbols]

 1, 1 'waveguide mechanism 2, 2' second or higher order diffraction grating 3 amplification mechanism 4 reflection mechanism 5 phase control (modulation) mechanism 6, 6 'active layer (gain part of waveguide mechanism) 7 waveguide active DBR Reference Signs List 8 radiation mode input taper portion of waveguide type active DBR 11 phase shift 20 high reflection structure 21 end face high reflection structure 30, 30 'reflector at waveguide end face 40 light receiving mechanism 50 substrate 53 current block region 55 transparent electrode 60 wire 70 electrode Reference Signs List 100 vertical output 200 waveguide end output 501 n-type InP 502 p-type InP 503 InGaAsP contact layer 504 proton irradiation region 505 p-side electrode (waveguide) 506 p-side electrode (amplification region) 507 n-side electrode 508 n-side electrode (conductive) Waveguide) 601 SI (semi-insulating) GaAs 602 GaAlAs cladding layer 603 AlAs 604 GaAs Optical functional device 800 optical fiber 900 external circuit of the selective oxidation layer 700 present invention tact layer 610 Zn diffusion region 650 AlAs603

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 10/02 F-term (Reference) 2H047 KA03 KA05 LA01 LA16 MA01 QA02 RA08 TA05 TA47 2H079 AA02 AA12 AA13 BA01 BA03 CA04 CA06 CA09 DA16 DA22 EA07 EB06 EB15 KA08 5F073 AA43 AA44 AA63 AA89 AB17 AB21 AB22 AB25 5K002 BA01 BA02 BA07 BA13 FA01

Claims (20)

[Claims] 1. A waveguide mechanism for guiding a light wave and having a gain or a loss, comprising: a first waveguide mechanism having a hologram capable of generating radiation mode light by being combined with the guided light wave; An amplification mechanism that amplifies and emits the radiation mode light emitted from the first waveguide mechanism; and a first mechanism that reflects the radiation mode light emitted from the amplification mechanism toward the first waveguide mechanism. An optical function device, comprising: a reflection mechanism; 2. The amplifying mechanism according to claim 1, wherein the amplifying mechanism is provided apart from the first waveguide mechanism so that a guided mode of the guided light wave becomes a single transverse mode. The optical functional device according to the above. 3. The optical function device according to claim 1, further comprising a phase control mechanism for controlling a phase of the radiation mode light reflected by the first reflection mechanism. 4. The apparatus is provided substantially in parallel with the first waveguide mechanism,
4. The apparatus according to claim 1, further comprising a second hologram, further comprising a second waveguide mechanism optically coupled to the first waveguide mechanism via the second hologram. The optical function device according to any one of the above. 5. The optical function device according to claim 1, wherein the hologram is a second-order or higher diffraction grating. 6. The optical functional device according to claim 5, wherein said diffraction grating has a blaze angle. 7. The optical function device according to claim 5, wherein the diffraction grating has a discontinuity in phase. 8. The method according to claim 1, wherein at least one of a period of said diffraction grating, a refractive index of said first waveguide mechanism, an amplification rate of said amplification mechanism, and a reflectance of said first reflection mechanism is equal to said first reflection mechanism.
The optical function device according to any one of claims 5 to 7, wherein the optical function device changes along a direction of the waveguide in the waveguide mechanism. 9. The apparatus according to claim 1, wherein at least one of said amplification mechanism and said first reflection mechanism is provided in a plurality along the direction of said waveguide of said first waveguide mechanism. 8. The optical functional device according to any one of items 7 to 7. 10. The light according to claim 1, further comprising a second reflection mechanism provided at at least one end of said first waveguide mechanism. Functional element. 11. An external light input or an external light output is defined as a waveguide mode from at least one end face of the first waveguide mechanism and a radiation mode from the first waveguide mechanism. The optical functional device according to any one of claims 1 to 10, wherein the optical function is performed in any one or both of the waveguide mode and the radiation mode. 12. A light collecting means for optically coupling to another optical element is provided at the external light input section or the external light output section. Item 12. The optical function element according to Item 11. 13. The optical function device according to claim 1, wherein at least one of the waveguide mechanism and the amplification mechanism includes a medium that generates a gain by optical excitation. 14. A medium according to claim 13, wherein said medium generating a gain by said optical excitation is a medium containing at least one of erbium (Er), Pr (praseodymium) and other rare earth elements. The optical functional device according to the above. 15. A light-transmitting electrode for supplying a current or applying an electric field is provided between said waveguide mechanism and said amplifying mechanism. Optical functional element. 16. The method according to claim 1, wherein a real part or an imaginary part of the refractive index of the waveguide mechanism can be changed by applying an electric field. The optical functional device according to the above. 17. The optical function device according to claim 1, further comprising a light receiving mechanism for the radiation mode light. 18. Modulating at least one of a refractive index of the first waveguide mechanism, an amplification rate of the amplification mechanism, a reflectance of the first reflection mechanism, and a phase of the diffraction grating. The optical function device according to claim 5, wherein the optical function device is configured to be capable of performing the operation. 19. The first waveguide mechanism has a modulator in which the hologram is not provided, and changes a real part or an imaginary part of a refractive index by applying an electric field to the modulator. 19. The optical function device according to claim 1, wherein the optical function device is configured to modulate light propagating through the modulation unit. 20. An optical communication device comprising the optical functional element according to claim 1.