KR100489809B1 - Tunable Semiconductor Laser And Method Thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength tunable semiconductor laser including a Fabry-Perot filter and an array of electrodes. The present invention can continuously change the traveling direction of an optical signal inside a cavity by applying an electric field or current to the electrodes. In addition, the wavelength can be continuously changed over a wide wavelength band by the continuous angle change of the intra cavity laser beam.

Description

Tunable semiconductor laser and method thereof {Tunable Semiconductor Laser And Method Thereof}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength tunable semiconductor laser, and more particularly to a semiconductor laser capable of varying wavelengths over an optical fiber communication band.

In the 80's and 90's, the explosion of information required an explosion in communication network capacity that required many channels allocated over a wide frequency range. Tunable semiconductor lasers are key components in a wide range of applications, including wavelength division multiplexing (WDM) and packet switching architectures. The network capacity of such a system increases with the number of wavelengths accessible by the tunable laser transmitter.

For this reason, expanding the wavelength tunable area of semiconductor lasers has been an important research area for decades. These studies have focused mainly on devices with integrated structures and predictable tuning algorithms that achieve wavelength variability with faster electrical effects than thermal effects at relatively low speeds.

Tunable semiconductor lasers are generally implemented in two different ways: monolithic integration or non-monolithic integration.

Non-monolithic technology mainly employs a method of wavelength tunable solid state laser or die lasers, which consists of an active material and a tunable filter inside the cavity mirror. A typical example of a non-monocular outer cavity includes a diffraction grating having a semiconductor portion having a facet mirror at one end and another end non-reflectively coated with a different mirror. The beam oscillates through the antireflective coated facet between the facet mirror and the diffraction grating. The diffraction grating rotates for wavelength tuning. The device offers a nearly 100nm single-mode tuning range and several milliwatts of power. In the lab, the technique demonstrated a wavelength variation from 1550nm to 240nm.

However, these external cavities must discard many of the conventional advantages of semiconductor lasers such as variable speed, small size, mass productivity, low cost and integration. These drawbacks provide strong motivation for tunable semiconductor lasers using the monolithic method.

Early types of monolithic tunable semiconductor lasers are distributed feedback (DBF) and distributed reflector (DBR) lasers. DBR and multisection DFB tunable lasers are limited in tunable regions by the fundamental problem that the partial wavelength change (Δλ / λ) does not exceed the effective refractive change (Δμ / μ) in the grating section of the device. In other words, the maximum tuning range is around 10 nm. Therefore, new schemes are needed that can overcome the limits of this wavelength tunable range.

In the early nineties, several research groups published promising wavelength tuning schemes. The first is a Y-cavity laser, and extended tuning can be realized with a simple modification of the Mach-Zender interferometer. The device offers 38nm tuning and has an easy fabrication advantage that requires no grating. This simple process and tuning scheme has the significant disadvantage of having a low side mode suppression ratio (SMSR) of 15-20 dB. The second device tunes with a tunable intra-cavity Grating-Assisted co-directional coupler (GACC) filter. This wavelength tunable range depends on Δμ / (μ ₁ -μ ₂ ) rather than Δμ / μ. Where μ _{1 and} μ ₂ are the effective refractive indices of the two coupled optical waveguides. Although showing a 57nm tuning range, the device increases filter tunability by reducing μ _1- μ ₂ , which has limitations that degrade side-mode suppression. In addition, the GACC has a very narrow design window to obtain an acceptable SMSR.

To date, the most successful devices commercially available are semiconductor lasers using a grating (SG) DBR sampled in a periodic manner (US Pat. No. 4,896,325). Sampled gratings provide periodic reflection peaks in the wavelength spectrum. Tuning is accomplished by shifting the reflection peaks of two sampled gratings with slightly different periods from each other. Despite the advantages of many SGDBR lasers over other tuning schemes, they still have some fundamental drawbacks. Wavelength tuning is achieved quasi-continously, not continuously. This means that moving from one wavelength to another is very complicated and time consuming. The user can only use wavelengths defined by the provider of the device. Superstructure grating DBR lasers are a slight modification to SGDBR lasers, which use chirped gratings instead of sampled gratings to generate periodic reflection maximums (US Pat. No. 5,325,325). The device not only shares semi-continuous tuning issues like SGDBR lasers, but also has manufacturing challenges requiring E-beam lithography. This can be an important obstacle to mass production.

Accordingly, the present invention is to solve the above-described problem, and provides a new method capable of continuously changing the wavelength over a wide wavelength band for semiconductor lasers.

Further, another object of the present invention is to solve the problems of non-monolithic and monolithic semiconductor lasers and to take advantage of each other only.

It is another object of the present invention to provide a wavelength tunable semiconductor laser having low mirror loss, using a high degree of perfection of dielectric coating, and implementing a simple and easy process.

In addition, another object of the present invention is to provide a wide band variable wavelength scheme that is immediately applicable to the optical fiber communication composed of a plurality of wavelength channels.

As a technical means for achieving the above object, one side of the present invention is formed on a substrate, the curved optical waveguide for guiding the optical signal by the cladding layer; An active region formed on a portion of the optical waveguide and generating an optical signal; An electrode array formed at one side of an active region and changing an advancing direction of an optical signal transmitted through the optical waveguide by applying an electric field or a current to a predetermined portion of the optical waveguide; A Febri-Perot filter for filtering only an optical signal of a selected wavelength according to a change in the traveling direction of the optical signal; And a curved mirror reflecting the one-wavelength optical signal passing through the Fabry-Perot filter.

On the other hand, the one electrode of the electrode array is configured to be different from the angle at which the advancing light is incident and the exit angle, and the inside of the one electrode is preferably configured to have a different refractive index than the outside according to the application of an electric field or current. More preferably, one electrode of the electrode array is triangular or trapezoidal in shape.

The wavelength tunable semiconductor laser may further include an output mirror which may be formed on the other side of the active region and outputs an optical signal transmitted from the optical waveguide. The output mirror may be a structure having a uniform grating engraved in a curved waveguide or a structure having a chirped grating engraved in a straight waveguide.

In addition, an antireflection thin film may be further included between the Fabry-Perot filter and the curved mirror.

The wavelength tunable semiconductor laser may further include a phase controller that can be formed on the other side of the active region.

On the other hand, it is preferable that the curved mirror is subjected to reflection coating.

In addition, the optical waveguide is preferably formed in a curved structure so that the light reflected from the Fabry Perot filter can escape the optical waveguide.

The Fabry-Perot filter may adopt a structure installed in one facet of a semiconductor laser, and may be formed of a TiO ₂ / SiO ₂ or SiN _x / SiO ₂ thin film. A curved mirror can be added on top of this Fabry Perot filter.

As another alternative, the Fabry-Perot filter may be formed of a cavity structure by alternately forming the cladding layer and an insulating material having a different refractive index from the cladding layer. Such a structure is a structure in which a Fabry-Perot filter is embedded in the semiconductor portion of the wavelength tunable laser. The insulating material usable may be silicon nitride. In addition, the curved mirror may be formed of a metal or dielectric material on the side of the Fabry-Perot filter to reflect the optical signal passed from the Fabry-Perot filter.

Another aspect of the present invention is to form a buffer layer, an optical waveguide core layer and an active layer of the lower cladding layer on the substrate; Patterning a core layer and an active layer to form an active region generating an optical signal on a portion of the optical waveguide and a curved optical waveguide core layer guiding the optical signal; Depositing an upper cladding layer and an ohmic layer over the entire structure; Performing an ion implantation process to insulate regions other than the formed optical waveguide; Manufacturing a semiconductor laser by forming an electrode including an electrode array for changing an advancing direction of an optical signal transmitted through the optical waveguide by applying an electric field or a current to a predetermined portion of the optical waveguide; And sequentially forming a Fabry-Perot filter and a curved mirror on one face of the semiconductor laser, wherein the Fabry-Perot filter has a light having one wavelength selected according to a change in the traveling direction of the optical signal by an electrode array. Only a signal is filtered, and the curved mirror provides a method of manufacturing a wavelength tunable semiconductor laser that reflects the optical signal of one wavelength passing through the Fabry-Perot filter.

Another aspect of the present invention is to form a buffer layer of the lower cladding layer, the core layer of the optical waveguide and the active layer on the substrate; Patterning a core layer and an active layer to form an active region generating an optical signal on a portion of the optical waveguide and a curved optical waveguide core layer guiding the optical signal; Depositing an upper cladding layer and an ohmic layer over the entire structure; Performing an ion implantation process to insulate regions other than the formed optical waveguide; Manufacturing a Fabry-Perot filter by etching the upper cladding layer into a group of grooves having a predetermined distance and depth in one region of the optical waveguide, and filling the groove with an insulating material having a different refractive index from the upper cladding layer; Forming a curved mirror on the side of the Fabry Perot filter; And forming an electrode including an electrode array configured to change an advancing direction of an optical signal transmitted through the optical waveguide by applying an electric field or a current to a portion of the optical waveguide between the Fabry-Perot filter and the active region. However, the Fabry-Perot filter filters only the optical signal of one wavelength selected according to the change in the propagation direction of the optical signal by the electrode array, and the curved mirror of the one wavelength passing through the Fabry-Perot filter A method of manufacturing a wavelength tunable semiconductor laser that reflects an optical signal is provided.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention. However, embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

(First embodiment)

1 is a diagram showing a wavelength tunable semiconductor laser 1 according to a first embodiment of the present invention. The wavelength tunable semiconductor laser 1 is composed of a semiconductor portion and a dielectric portion, and the semiconductor portion can be configured to include an active region 14 and an electrode array 18 of a general semiconductor laser, and the phase control region 15 and an output mirror ( 16), wherein the dielectric portion includes a Fabry-Perot filter 13 and a curved mirror 17. Meanwhile, the antireflective thin film 11 may be further included between the Fabry-Perot filter 13 and one facet. The antireflective thin film 11, the Fabry-Perot filter 13 and the curved mirror 17 can be fabricated by growing on one facet of the semiconductor block using a dielectric material.

The Fabry-Perot filter 13 is an element that filters optical signals of different wavelengths according to the angle of incidence, and the wavelength of light transmitted through the filter is related to the angle of incidence at the filter by equation (1).

λ = λ _{0 /} cosθ (1)

Λ ₀ is the wavelength of light incident perpendicularly to the filter. The Fabry-Perot filter 13 is not particularly limited as long as it can perform the function of the above-described filter, and can be variously used. For example, the TiO ₂ / SiO ₂ thin film is alternately rotated once or more at 180 nm / 200 nm. It can be prepared by forming. In addition, it is also possible to alternately form a silicon oxide film (SiN _x ) and a silicon nitride film.

The Fabry-Perot filter 13 is designed to give a narrow spectral band with sufficient SMSR in a single cavity mode. The curved mirror 17 is designed to reflect light incident through the Fabry-Perot filter 13 in its original path. On the other hand, anti-reflective coating may be applied to one facet 11 to minimize reflections from the interface between the semiconductor and the dielectric. The optical waveguide of the laser cavity is bent at an appropriate angle and radius of curvature to remove light reflected from the front surface of the Fabry-Perot filter 13. On the other hand, the active region 14 of the semiconductor portion can also be formed in a curved structure.

The curved mirror 17 can be formed together with the Fabry Perot filter 13 by a continuous process, any available technique can be used for the spherical shape of the mirror, and reflects light according to the incident light path. Perform. As an example of the material usable as the curved mirror 17, a fabrication material of the Fabry-Perot filter 13 may be used, and the alteration of the thickness of the material formed alternately may be made so that reflection may occur. For example, the TiO ₂ / SiO ₂ thin film may be manufactured by alternately forming one or multiple circuits.

The optical waveguide 12 guides the optical signal, and the optical waveguide 12 is bent at an arbitrary angle θ ₁ and a radius of curvature r ₁ . The specific values λ ₁ , r ₁ are determined by the core and clad material of the optical waveguide. θ ₁ should be large enough to remove light reflected from the front surface of the Fabry-Perot filter 13. The radius of curvature r ₁ must be large enough to minimize the loss of light guided by bending. For example, the angle θ ₁ may be implemented to be greater than the critical angle at which the light reflected by the Fabry-Perot filter 13 escapes the waveguide and is less than 30 °. If the optical waveguide consists of an InGaAsP core and InP cladding and the index difference is Δn = 0.189, the critical angle is 9.7 °.

The electrode array 18 may continuously change the traveling direction of the optical signal inside the cavity by applying an electric field or a current. That is, the angle of incidence and the angle of exit to one electrode (for example, one triangle) of the electrode array 18 are configured differently, and the inside of the triangle has a different refractive index from the outside depending on the application of an electric field or current. It is composed. Through this principle, the direction of light can be changed continuously. For example, the electrode array 18 can be any shape of polymorph with triangles, trapezoids or non-parallel sides. The optical waveguide below the electrode array is fan-out to accommodate the changed direction of travel of the light. This will be described later in detail. However, if the structure described above is applied, it is obvious that various modifications may be made to the shape of the unit electrode in the electrode array 18.

2A and 2B show embodiments of electrode arrays. FIG. 2A shows a triangular electrode 31 and FIG. 2B shows an inverted image of FIG. 2A. 2A and 2B, optical signals are refracted in different directions. It is possible to design electrodes having many different shapes, such as triangles as well as trapezoidal shapes, and it is natural that such design forms are included in the present invention.

Meanwhile, the active region 14, the phase control region 15, and the output mirror 16 constituting the semiconductor unit are components used in a general semiconductor laser, and a detailed description thereof will be omitted for convenience of description. The phase control region 15 plays a role of satisfying the resonance conditions of the cavity in order to realize wavelength variation, and is not an essential configuration.

However, the output mirror 16 of the laser cavity may be made of one facet, which is a cutting surface of the semiconductor laser as shown in FIG. 1, or may be formed in various ways such as a grating specially designed to secure a sufficiently wide band band. In addition, when integrating a semiconductor optical amplifier (SOA) or the like with a semiconductor laser, various kinds of output mirrors 16 other than simple facets may be introduced. 3A, 3B, and 3C show an example of fabrication of the output mirror 16.

3A shows a dielectric mirror 16 coated on one facet of a semiconductor laser. Facets are cases formed of multiple coated layers.

FIG. 3B shows a uniform grating 41 carved into a curved waveguide 42, and FIG. 3C shows a chirped grating 43 carved into a straight waveguide. The grating mirror 16 of FIGS. 3B and 3C is designed to cover the entire band of the tunable spectrum. The structure of FIG. 3B has an advantage of easy processing using holography lithography, and the structure of FIG. 3C has advantages of a straight waveguide and a small loss, but has a disadvantage of using an E-beam lithography process.

Hereinafter, the operation principle of the wavelength tunable semiconductor laser 1 will be described in detail with reference to FIG. 1.

First, the optical signal generated in the active region 14 is guided along the optical waveguide 12. The case where the traveling light is continuously changed by the electrode array 18 will be described in detail by taking the case of the InGaAsP core and InP cladding of the optical waveguide as an example. Optical waveguide 12, if the angle θ ₁ is the angle θ ₂ 15 ° curving necessary for 70nm tuning is therefore calculated to be about 22.6 °, from θ ₁ θ ₂ should vary by about 7.6 °. Therefore, assuming that the core of the optical waveguide 12 is an InGaAsP material having a refractive index of n = 3.359 and the cladding layer is InP, the index difference between the waveguide core and the cladding is about Δn = 0.189 so that the Fabry-Perot filter 13 The critical angle at which light reflected from the waveguide escapes the waveguide is about 9.7 °, and the bending angle (θ ₁ ) of the optical waveguide 12 is 15 ° is sufficiently larger than the critical angle.

On the other hand, assuming that the largest index change at the highest current is about 0.516% = (1558 nm-1500 nm) / 1500 nm, the incident light is incident vertically, and the emitted light is emitted through a 45 ° triangle. Each time the change in travel angle is calculated, Δθ = 0.2965 °. That is, the propagation angle changes each time the light passes one triangular electrode because the incident angle and the exit angle are different, and Δθ = 0.2965 ° is vertically incident and is emitted non-vertically at 45 ° hypotenuse. The refractive index of the optical waveguide portion below the triangle is different from other regions due to the application of electric field or current, and varies by the above-described angle according to the refractive index law. In this way, the number of electrodes for each 7.6 ° angle change is 26, and when the height of the first triangle is 2 μm, the total length of the electrode is 315 μm by computer calculation and the height of the last triangle is 57 μm. This is a figure that can be realized in a semiconductor process.

The refracted optical signal is then incident on the Fabry-Perot filter 13. The Fabry-Perot filter 13 is an element that filters optical signals of different wavelengths according to the angle of incidence. The wavelength of the optical signal according to the angle incident on the Fabry-Perot filter 13 is as follows.

λ = λ _{0 /} cosθ

Here, λ ₀ is the wavelength of the optical signal incident on the filter perpendicularly.

The optical signal of the wavelength thus selected is reflected backwards in the same optical path as the incident optical path by the sphere model of the high-resolution coated dielectric mirror 13. In this way the laser inside the cavity oscillates between the output mirror 16 and the curved mirror 13.

Hereinafter, an example of fabrication of the wavelength tunable semiconductor laser 1 according to the preferred embodiment of the present invention will be described with reference to FIG. 4. 4 is a cross-sectional view of the semiconductor laser of FIG. 1, taken along a cross section bent along an optical waveguide.

First, an n-InP buffer layer 22 is grown on the n-InP substrate 21 to have a thickness of, for example, 3000 ns, and the optical waveguide 23 and the multiple quantum wall active layer 24 are formed on the buffer layer 22. Deposit continuously. The optical waveguide 23 is a mono-layer having a thickness of 2000 to 4000 microns using a quarterary such as InGaAsP, and the active layer 24 is composed of a multi-quantum well structure using a quaternary such as InGaAsP. It is possible. Next, after the active layer 24 is patterned using a series of lithography and etching processes, the optical waveguide 23 is also patterned. At this time, the optical waveguide 22 is preferably formed to have a curved structure.

Thereafter, the InP P-cladding layer 25 and the P-InGaAs layer 26 for the ohmic layer are deposited, and an ion implantation process is performed to insulate the regions other than the optical waveguide formed. The ion implantation process is a process of insulating the region in which the dutron is implanted by covering the region of the patterned core layer 23 with a mask and injecting a deutron.

Next, after the separation process step for separating the electrode array, the active region and the like to form a metal electrode 27 by depositing Pi / Pt / Au with a thickness of 200/200 / 3000Å respectively. The electrodes are formed in the electrode array portion on the optical waveguide. The metal which can be formed by the electrode array is not particularly limited and various metals are possible, for example, gold (Au) can be deposited to a thickness of 100 to 200 nm. In this case, as described above, the shape of the electrode may be, for example, a structure in which a triangular shape is arranged.

Next, the Fabry-Perot filter 13 may be installed in one facet of the laser after all the processes of the semiconductor portion have been performed. Preferably, the antireflection thin film 11 is formed on one facet. Then, the curved mirror 13 is formed on the Fabry-Perot filter 13, for example, it can be manufactured in a manner such as high power laser cutting, wet etching through lithography. Such a vertical structure of the dielectric part is made of a spherical curved mirror along the vertical direction.

(Second embodiment)

5 is a view showing a wavelength tunable semiconductor laser 1 according to a second embodiment of the present invention. Referring to the difference from the first embodiment, the second embodiment manufactures the Fabry-Perot filter and the curved mirror monolithically in the semiconductor portion. FIG. 5 is a diagram illustrating a case where a Fabry-Perot filter and a curved mirror are embedded in a semiconductor unit, and FIG. 6 is a cross-sectional view of the wavelength tunable semiconductor laser structure of FIG. 5.

In this case, since it is made of a semiconductor process such as adjusting the thickness of each groove (46 in FIG. 6) of the Fabry-Perot filter (44 in FIG. 5), which is made of repeated refractive index changes, the fabrication process is much easier. The radius of curvature and the center of curvature of the spherical mirror can be precisely adjusted.

Referring to FIG. 6, the Fabry-Perot filter (44 in FIG. 5) periodically excavates a groove of a specific width on the optical waveguide 23 and has a refractive index different from that of the core or cladding of the waveguide, as shown in FIG. 6. 46). For example, a groove is formed in the InP cladding layer 25 of several μm, and a material having a different refractive index from the cladding layer 25 is formed inside the groove (for example, an insulating material such as a silicon nitride film or a silicon oxide film). Fill it. On the other hand, the depth, width and number of grooves are selected according to the characteristics of the filter is not particularly limited and can be variously. In addition, the material to be filled in the grooves can also be variously selected according to the characteristics of the process and any material is included in the present invention.

When the silicon nitride film is filled in the grooves of the Fabry-Perot filter (44 in FIG. 5), the thickness (width) of the InP cladding layer may be 170 to 200 nm, and the thickness of the silicon nitride film may be about 300 nm, and one InP may be used. When defining the cladding layer and one silicon nitride film as one pair, 5-10 pairs are arranged in succession to form one group (however, in FIG. The two groups may be spaced apart from each other at a predetermined interval. On the other hand, the two predetermined intervals are designed to exhibit the characteristics of the cavity in order to perform the function of the Fabry-Perot filter, and can be set to, for example, half-wave or 1.5 times the half-wave. On the other hand, the depth of the groove can be formed in the cladding layer 25 or a part of the optical waveguide 23.

The curved mirror 47 may be formed by forming a cross section as shown in FIG. 6 in the optical waveguide 23 by lithography and etching and depositing gold or a reflective dielectric material.

Hereinafter, a manufacturing example of the wavelength tunable semiconductor laser 1 according to the second embodiment of the present invention will be described in detail with reference to FIGS. 7A to 13B.

Referring to FIGS. 7A and 7B, the core layer 23 of the optical waveguide has a thickness of 2000 to 4000 mV using a n-InP buffer layer 22 of about 3000 mV and a quarterary such as InGaAsP on the n-InP substrate 21. And a multiple quantum wall active layer 24 composed of an active layer, for example, InGaAsP-based material, which can be used as a general active layer of a semiconductor laser, is continuously formed to a thickness of 2000 to 4000 microns. Thereafter, an active region having a curved structure is formed using the active region mask shown in FIG. 7B. Detailed processes to be formed may employ conventional lithography and etching processes.

8A and 8B, the core layer 23 is then patterned using a lithography process to define the core region of the optical waveguide. As shown in FIG. 8B, a part of the optical waveguide is designed to form a Fabry-Perot filter and a curved mirror.

9A and 9B, a P-cladding layer 25 of about 2 μm is formed on the entire structure of InP material, and an P-InGaAs layer 26 for an ohmic layer is grown thereon. An ion implantation process is performed using the mask of FIG. 9B. The ion implantation process is a process of insulating the region in which the dutron is implanted by covering the region of the patterned core layer 23 with a mask and injecting a deutron.

10A and 10, a separation process of separating a region A, an electrode array region B, an active region c, and a phase control region D from which a Fabry-Perot filter is to be formed is performed. . Fig. 10B shows a mask pattern when performing this process. The region B in which the electrode array is formed is formed in a triangular electrode shape.

Referring to FIG. 11, a Fabry Perot filter 44 is manufactured. The Fabry-Perot filter 44 can be formed by periodically digging a groove of a certain width on the optical waveguide 23 and having a refractive index filled with a material 46 different from the core or clad of the waveguide. Fine patterning may be prepared using holographic lithography, etc., in addition to conventional lithography.

Referring to Fig. 12, a curved mirror 47 is produced. The curved mirror 47 forms an etch stop layer 40 by lithography or the like and is etched with a mask to form a cross section as shown in FIG. 6 in the optical waveguide 23. Curved mirror 47 may be formed by depositing gold or a reflective dielectric material. It is of course possible to form a multilayer. In addition, the depth at which the curved mirror 47 is formed is not particularly limited, and it is possible to form the buffer layer 22, the core layer 23, or the clad layer 24.

13A and 13B, electrodes are formed in some regions of the entire structure. 13B shows a pattern mask for forming an electrode. The electrode is formed on the electrode array region B, the active region C, and the phase control region D as shown in FIG. 13A. The material usable as the electrode, for example, deposits Pi / Pt / Au 200/200/3000 mm thick to form the metal electrode 27.

As mentioned above, although this invention was demonstrated in detail through the specific Example, this invention is not limited to this, It is clear that the deformation | transformation and improvement are possible by those of ordinary skill in the art within the technical idea of this invention.

Therefore, as described above, the present invention can realize the above-mentioned object, and it is possible to continuously change the wavelength over a wide wavelength band, and to use the monolithic device as much as possible to expect high output and fast tuning time.

1 is a view showing a wavelength tunable semiconductor laser 1 according to a preferred embodiment of the present invention.

2A and 2B illustrate an example of the electrode array of FIG. 1.

3A, 3B and 3C are diagrams showing an example of manufacturing the output mirror of FIG.

4 is a cross-sectional view illustrating an example in which the wavelength tunable semiconductor laser of FIG. 1 is actually implemented.

FIG. 5 is a diagram illustrating an example in which the Fabry-Perot filter and the curved mirror of FIG. 1 are formed in a semiconductor portion.

FIG. 6 is a cross-sectional view of the curved mirror and Fabry-Perot filter portion of FIG. 5. FIG.

7A, 7B to 13A, and 13B are flowcharts of an example of fabricating a wavelength tunable semiconductor laser according to an embodiment of the present invention.

Claims (26)

A curved optical waveguide formed on the substrate and guiding the optical signal by the cladding layer; An active region formed on a portion of the optical waveguide and generating an optical signal; An electrode array formed at one side of the active region and changing an advancing direction of an optical signal transmitted through the optical waveguide by applying an electric field or a current to a predetermined portion of the optical waveguide; A Febri-Perot filter for filtering only an optical signal of a selected wavelength according to a change in the traveling direction of the optical signal; And And a curved mirror reflecting the optical signal of one wavelength passing through the Fabry-Perot filter. The method of claim 1, The one electrode of the electrode array is configured to have a different angle of incidence and exit angle of the traveling light, the inside of the one electrode is configured to have a refractive index different from the outside according to the application of an electric field or current Variable semiconductor laser. The method of claim 2, One electrode of the electrode array is a wavelength tunable semiconductor laser, characterized in that the triangular shape or trapezoidal shape. The method of claim 1, And an output mirror formed on the other side of the active region and outputting an optical signal transmitted from the optical waveguide. The method of claim 4, wherein And the output mirror has a structure having a uniform lattice engraved in a curved waveguide or a chirped lattice engraved in a straight waveguide. The method of claim 1, A wavelength tunable semiconductor laser further comprising an antireflection thin film between the Fabry-Perot filter and the curved mirror. The method of claim 1, The wavelength tunable semiconductor laser is formed on the other side of the active region, further comprising a phase controller. The method of claim 1, A wavelength tunable semiconductor laser, characterized in that the curved mirror is subjected to reflection coating. The method of claim 1, The optical waveguide is a wavelength tunable semiconductor laser, characterized in that formed in a curved structure so that the light reflected from the Fabry Perot filter escapes the optical waveguide. The method of claim 1, The Fabry-Perot filter is a wavelength tunable semiconductor laser, characterized in that the structure is installed on one facet of the semiconductor laser. The method of claim 10, The Fabry-Perot filter is a wavelength tunable semiconductor laser, characterized in that formed of a thin film of TiO ₂ / SiO ₂ or SiN _x / SiO ₂ . The method of claim 10, The curved mirror is a wavelength tunable semiconductor laser, characterized in that formed on top of the Fabry-Perot filter. The method of claim 1, The Fabry-Perot filter is a wavelength tunable semiconductor laser, characterized in that the cladding layer and the cladding layer and the insulating material having a different refractive index is formed several times alternately formed of a cavity structure. The method of claim 13, The insulating material is a wavelength tunable semiconductor laser, characterized in that the silicon nitride film. The method of claim 13, And the curved mirror is formed of a metal or a dielectric material on the side of the Fabry-Perot filter to reflect the optical signal passed from the Fabry-Perot filter. Forming a buffer layer of a lower cladding layer, a core layer of an optical waveguide, and an active layer on the substrate; Patterning the core layer and the active layer to form an active region generating an optical signal on a portion of the optical waveguide and a curved optical waveguide core layer guiding the optical signal; Depositing an upper cladding layer and an ohmic layer over the entire structure; Performing an ion implantation process to insulate regions other than the formed optical waveguide; Manufacturing a semiconductor laser by forming an electrode including an electrode array which changes an advancing direction of an optical signal transmitted through the optical waveguide by applying an electric field or a current to a predetermined portion of the optical waveguide; And And sequentially forming a Fabry-Perot filter and a curved mirror on one facet of the semiconductor laser, The Fabry-Perot filter filters only the optical signal of one wavelength selected according to the change in the propagation direction of the optical signal by the electrode array, and the curved mirror passes through the Fabry-Perot filter. A method of manufacturing a wavelength tunable semiconductor laser, which reflects a signal. The method of claim 16, The Fabry-Perot filter is a method of manufacturing a wavelength tunable semiconductor laser, characterized in that formed in a thin film of TiO ₂ / SiO ₂ or SiN _x / SiO ₂ . The method of claim 16, And forming an antireflective thin film between the Fabry-Perot filter and the curved mirror. Forming a buffer layer of a lower cladding layer, a core layer of an optical waveguide, and an active layer on the substrate; Patterning the core layer and the active layer to form an active region generating an optical signal on a portion of the optical waveguide and a curved optical waveguide core layer guiding the optical signal; Depositing an upper cladding layer and an ohmic layer over the entire structure; Performing an ion implantation process to insulate regions other than the formed optical waveguide; Manufacturing a Fabry-Perot filter by etching the upper cladding layer into a group of grooves having a predetermined distance and depth in one region of the optical waveguide, and filling the groove with an insulating material having a different refractive index from the upper cladding layer; Forming a curved mirror on the side of the Fabry Perot filter; And Forming an electrode including an electrode array for changing an advancing direction of an optical signal transmitted through the optical waveguide by applying an electric field or a current to a portion of the optical waveguide between the Fabry-Perot filter and the active region. But The Fabry-Perot filter filters only the optical signal of one wavelength selected according to the change in the propagation direction of the optical signal by the electrode array, and the curved mirror passes through the Fabry-Perot filter. A method of manufacturing a wavelength tunable semiconductor laser, which reflects a signal. The method of claim 19, The curved mirror is a method of manufacturing a wavelength tunable semiconductor laser, characterized in that formed of metal or dielectric material on the side of the Fabry-Perot filter to reflect the optical signal passed from the Fabry-Perot filter. The method of claim 19, The insulating material having a refractive index different from that of the upper cladding layer is a silicon nitride film. The method according to any one of claims 16 to 21, The one electrode of the electrode array is formed with a different angle of incidence and exit angle of the traveling light, the inside of the one electrode has a refractive index different from the outside according to the application of an electric field or current Manufacturing method. The method according to any one of claims 16 to 21, A method of manufacturing a wavelength tunable semiconductor laser, characterized in that it further comprises the step of forming a phase controller on the other side of the active region. The method according to any one of claims 16 to 21, The method of manufacturing a wavelength tunable semiconductor laser characterized in that it further comprises the step of reflecting coating on the curved mirror. The method according to any one of claims 16 to 21, Manufacturing an output mirror for outputting an optical signal transmitted from the optical waveguide on the other side of the active region. The method according to any one of claims 16 to 21, And the output mirror has a structure having a uniform lattice engraved in a curved waveguide or a structure having a chirped lattice engraved in a straight waveguide.