KR100626270B1 - Widely Tunable Coupled-Ring Reflector Laser Diode - Google Patents

Abstract

 According to the present invention, an integrated coupling resonator reflector (CRR) consisting of two ring resonators designed to allow optical power exchange through a directional coupler and a linear waveguide coupled thereto is integrated with a gain material. It is to realize a laser. In this configuration, if the FSR (free spectral range) of the two ring resonators combined is slightly different (i.e. slightly different circumferential length of the two resonators), and the refractive index is properly adjusted, the amount of reflectance generated in the FSR period is determined. The maximum reflectance at the wavelength that is the largest in the wavelength and separated by an integer multiple of the FSR period from the wavelength representing the maximum reflectance gradually decreases. In addition, if the refractive index difference between the two ring resonators is properly adjusted, the maximum reflectance wavelength can be changed over several tens of nm even with small refractive index changes. By using the reflection characteristics of the CRR it is possible to implement a wide-band wavelength tunable laser.

 Laser Diodes, Wideband Tunable Lasers, Optical Waveguides, Reflectors, Ring Resonators, Resonators, Optical Integrated Circuits

Description

 Wideband Tunable Coupled-Ring Reflector Laser Diode

 1A is a schematic configuration diagram of an extraction grating distribution Bragg reflective semiconductor laser diode that can vary the wavelength of an oscillated laser according to the prior art;

1B is a conceptual diagram of a diffraction grating provided in the SG-DBR region of the laser diode shown in FIG. 1A;

FIG. 1C schematically shows a reflection spectrum of the SG-DBR region in the laser diode shown in FIG. 1A;

2a is a conceptual diagram of a diffraction grating of a Bragg reflection stage modulated by a grating period, according to another conventional technique,

FIG. 2B schematically illustrates a reflection spectrum by the diffraction grating shown in FIG. 2A;

3 is a schematic perspective view of a broadband wavelength variable CRR (Coupled-Ring Reflector) laser diode;

4A is R ₀ = R ₁ = 50 μm in the CRR of FIG. 3, and n _{eff 0} = n _eff1 = 3.29, where the coupling ratio κ _in between the linear waveguide and the ring waveguide and the coupling ratio κ ₀ between the ring and the ring are assumed to be 0.64 and 0.08, respectively,

FIG. 4B shows R ₀ at CRR of FIG. = 50 μm, R ₁ = ⁵² μm, the reflection spectrum when the ring resonator 0 has a refractive index of 3.29 and the ring resonator 1 has a refractive index of 3.29 + 1.9 × 10 ⁻⁴ ,

4C shows R ₀ at CRR of FIG. = 50 μm, R ₁ = ⁵² μm, the reflection spectrum when the ring resonator 0 has a refractive index of 3.29 and the ring resonator 1 has a refractive index of 3.29 + 3.8 × 10 ⁻⁴ ,

FIG. 4D shows R ₀ at CRR of FIG. = 50 μm, R ₁ = ⁵² μm, the reflection spectrum when the ring resonator 0 has a refractive index of 3.29 and the ring resonator 1 has a refractive index of 3.29 + 5.7 × 10 ⁻⁴ ,

5 is a schematic plan view of a CRR composed of a ring resonator including a total reflection mirror and a multimode interference coupler;

FIG. 6 is a schematic perspective view of a broadband wavelength-variable coupled-ring reflector (CRR) laser diode incorporating a Fabry-Perot laser diode fabricated from InGaAsP series in hybrid with a CRR implemented in silica or polymer materials.

<Description of Signs of Major Parts in Drawings>

30: n-type InP substrate 31: p-type InP cladding layer

32a: multi-quantum well active layer 32b: InGaAsP passive waveguide layer

33 n-type electrode 34 p-type electrode (active layer current injection electrode)

35 ridge structure for waveguide formation 36a: refractive index control electrode

36b: refractive index control electrode 36c: refractive index control electrode

37a: CRR ring resonator 0 37b: CRR ring resonator 1

37c: CRR linear waveguide 38: reflection cross section (reflectance: R _L )

39: reflection by CRR (reflectance: R _R ) 40: antireflection coated cross section

50: total reflection mirror 51: multimode interference coupler

52: incident wave 53 reflected wave

54 transmission wave 60 silica or polymer substrate

61a: silica or polymer lower clad layer

61b: silica or polymer waveguide layer

61c: silica or polymer top clad layer

62a: multi-quantum well active layer 62b: InGaAsP top clad layer

62c: InGaAsP lower cladding layer 63a: reflection cross section (reflectance: R _L )

63b: antireflection coated cross section 64: p-type electrode (active layer current injection electrode)

65: Ridge structure for forming laser diode waveguide

66a: refractive index control electrode 66b: refractive index control electrode

66c: Refractive index control electrode 67a: CRR ring resonator 0

67b: CRR ring resonator 1 67c: CRR linear waveguide

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor laser diodes, and more particularly to a coupled tunable coupler ring reflector laser diode capable of varying the wavelength of a wide band using the wavelength selective reflection characteristics of the mutually coupled rings. .

As the amount of information transmitted through communication increases rapidly, wavelength division optical signal transmission is used as a method for increasing transmission capacity. This method uses non-coherence between light waves of different colors to transmit optical signals of different wavelengths (channels) through one optical fiber, thereby increasing the transmission speed. The wavelength division optical signal transmission is advantageous to ensure the scalability and flexibility of the optical communication system. In order to transmit the optical signal of the wavelength division method, a laser diode having a fixed wavelength of several wavelength bands or a laser diode capable of varying the wavelength is required.

Tunable laser diodes have several advantages over conventional wavelength-fixed laser diodes, which can reduce the number of back-up light sources for system maintenance and maintenance, provide dynamic wavelengths, and simplify network control software. Can be. These advantages make tunable laser diodes an essential component for optical network development in all application areas, from subscriber networks to macro and long-haul networks.

Tunable laser diodes have high power (> 10mW), variable wavelength (> 32nm), fast variable wavelength (> 10ns), and fast direct modulation (> 2.5) to meet the specifications required by many application areas. Gbps) and mass production must be available.

Typical tunable laser diodes developed or proposed to date include a sampled grating distributed Bragg reflector (SG-DBR) laser diode, and a periodic grating period-modulated Bragg reflector (SGG). (DBR) laser diodes, grating-assisted codirectional-couplers with sampled grating reflectors (GCSR) laser diodes combined with extraction grating reflectors.

Hereinafter, exemplary wavelength-variable laser diodes according to the related art will be described with reference to the accompanying drawings.

FIG. 1A schematically illustrates a structure and a control circuit of a sampled grating distributed Bragg reflector (SG-DBR) laser diode described in US Pat. No. 4,896,325.

In the SG-DBR laser diode shown in FIG. 1A, a total of four SG-DBR regions 11 and 14 at both ends of the laser diode, a gain region 12 in which light waves are generated, and a phase adjusting region 13 are provided. It is composed of areas. In order to vary the wavelength of the laser output from the SG-DBR laser diode, a vernier control circuit (17) for continuous wavelength variation and an offset control circuit (18) for discontinuous wavelength shifting are provided. In addition, an external control circuit such as a phase control circuit 16 and a gain control circuit 15 in the phase region is required.

The basic operation principle of the SG-DBR laser diode is as follows. Applying a current to the gain region 12 generates light waves distributed over a wide wavelength by spontaneous emission. The SG-DBR region at both ends allows only the light waves of a specific wavelength to resonate in the laser diode so that the laser diode oscillates at the wavelength.

Here, a sampled grating structure as shown in FIG. 1B is formed in the SG-DBR region illustrated in FIG. 1. This extraction grating has the reflection spectral characteristics as shown in FIG. 1C. The wavelength of the center peak of the reflection spectrum is the Bragg wavelength λ _B determined by the diffraction grating period Λ and the spacing between wavelengths having each peak value is determined by the period Z of the extraction grating. That is, the SG-DBR regions 11 and 14 of the extraction gratings having different periods are integrated at both ends, so that the laser diode oscillates at the wavelength of the corresponding peak among the peaks of the reflection spectrum of the SG-DBR regions 11 and 14. Done.

When the refractive indices of the SG-DBR regions 11 and 14 are changed by current or the like, each peak of the reflection spectrum is shifted while maintaining the interval between wavelengths. The shift of the reflection peak causes the wavelength of the matching reflection peak to be changed, so that the oscillation wavelength can be varied. The phase adjusting region 13 adjusts the interval between the longitudinal modes of the gain region 12 generated by the SG-DBR to match the longitudinal mode to the continuous wavelength variable or the reflected peak to maximize the power of the oscillation wavelength. It plays a role. With this principle, continuous / discontinuous wavelength variability is possible by appropriately adjusting the refractive indices of the SG-DBR regions 11 and 14 and the phase adjusting region 13 at both ends.

However, since the SG-DBR laser diode needs to change the refractive index of the SG-DBR region and the phase region of the both ends in order to change the wavelength, the external circuit for controlling the device is complicated and the SG integrated at both ends for the wavelength variable. There is a structural limitation that the output light efficiency is lowered by the loss occurring in the -DBR region.

In order to overcome these structural limitations, studies are being actively conducted to increase output optical power by integrating a semiconductor optical amplifier (SOA), but there are difficulties in manufacturing due to the complexity of the laser diode structure. This happens.

FIG. 2A is a conceptual diagram of a diffraction grating of a Bragg reflection (SSG-DBR) laser diode periodically modulated to vary the wavelength of an output laser, and FIG. 2B is a reflection generated by the diffraction grating shown in FIG. 2A. It is a figure which shows the spectrum schematically. Hereinafter, another representative SSG-DBR laser diode, which is a tunable laser diode, will be described with reference to FIGS. 2A and 2B.

SSG-DBR laser diodes are described in US Pat. No. 5,325,392. The SSG-DBR laser diode basically operates in a similar structure and principle to the SG-DBR laser diode shown in FIG. That is, in FIG. 1, the SSG-DBR region is provided instead of the SG-DBR region.

As shown in FIG. 2A, the structure of the diffraction grating provided for the variable wavelength is different from the SG-DBR. Due to the spatial modulation of the diffraction grating, the reflection spectrum has the characteristics as shown in FIG. 2B. The spacing of each reflection peak is determined by the period Z and each reflection peak size is determined by the diffraction grating spatial modulation.

However, the SSG-DBR laser diode has a wide wavelength variable region and can produce a relatively constant output optical power according to the wavelength variable, but similar to the SG-DBR laser diode, loss occurs in the SSG-DBR region at both ends and complex diffraction. Due to the lattice structure there is a problem that can have a lot of difficulties in manufacturing.

In addition to the tunable laser diode described above, the tunable laser diode according to the prior art includes a GCSR laser diode and a tunable twin-guide laser diode. However, since the laser diode of such a structure needs to repeat re-growth and etching to manufacture, it is difficult to manufacture and is not suitable for mass production.

That is, the wavelength tunable laser diode of the prior art has a disadvantage in that the structure is complicated, the manufacturing process is complicated, the output light efficiency is low, and the wavelength tunable control is complicated.

 An object of the present invention is to provide a wideband tunable laser diode using a flat waveguide reflector that can replace a conventional wavelength selective reflector including a diffraction grating structure.

The use of a coupled ring resonator (CRR) structure as a wavelength selector eliminates the need for the fabrication of a distributed Bragg reflector (DBR) grating, resulting in a low-cost, high-volume, broadband, tunable laser diode. Can be provided.

In the present invention, the radius of the two rings included in the CRR structure is slightly different, and the effective refractive index of the two rings is appropriately adjusted relatively differently, so that the reflection occurs largely only at the wavelength at which both rings can resonate simultaneously. The resonator is designed to oscillate at that wavelength. By this concept, the range of oscillation wavelength that can be adjusted reaches several tens of nanometers.

 DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. do. The present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, only the present embodiments are intended to complete the disclosure of the present invention and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you.

(Example 1)

FIG. 3 is a schematic perspective view of a wide-band tunable ring resonator (CRR) laser diode capable of varying a wavelength of a laser oscillated according to a first preferred embodiment of the present invention.

The biggest feature of the CRR tunable laser diode according to the present embodiment is to use the CRR structure as the wavelength selective reflector as shown in FIG. 3. As illustrated in FIG. 3, the CRR structure is a structure in which two ring resonators 37a and 37b are coupled to exchange optical power with each other, and the ring resonators are coupled to an input / output linear waveguide. Such a CRR structure can simplify the process of the tunable laser diode by realizing the reflector without employing a grating structure. The wavelength variable characteristic of this CRR is demonstrated later.

The CRR laser diode according to the present embodiment can vary the wavelength of the laser output to a wide range (more than 50 nm) continuously / discontinuously by changing the refractive index of the lower region of the refractive index control electrodes 36a and 36b provided in the ring resonator. It becomes possible.

In the embodiment of FIG. 3, the case of the ridge structure 35 is considered to realize the optical waveguide. An optical waveguide may be a buried structure that is widely used in the fabrication of laser diodes, but for the purpose of describing the present embodiment, a ridge structure is illustrated for simplicity. In the case of the ridge structure type, the p-type InP cladding layer 31 is grown on the multi-quantum well active layer 32a and the InGaAsP passive waveguide layer 32b in contact with the n-type InP. After growing a p-type ohmic contact layer for forming an electrode on the layer, an optical amplification region and refractive index control formed under the p-type electrode 34 and the p-type electrode using a mask of the form shown in FIG. The phase control region 36c formed below the electrode 36c, the refractive index control electrode, and the passive waveguide region composed of the ring resonators 37a and 37b of the CRR and the linear waveguide 37c are simultaneously formed. As such, the amplification region, the phase control region, and the ring resonator passive waveguide region are simultaneously formed through one lithography operation, thereby simplifying the process. Herein, the wafer growth structure is intended to show an embodiment of a tunable CRR laser diode, and a specific growth pattern of the wafer may be designed in various forms according to a manufacturing situation. Electrodes are formed on the p-type InP cladding layer 31, p-type electrodes 34 for current injection on the multi-quantum well active layer 32a, and refractive index control electrodes 36a and 36b on the ring resonator passive waveguide layer. , 36c). In particular, the refractive index is controlled by thermo-optic or electro-optic effects by appropriately adjusting the current injected or the applied reverse bias voltage to the electrodes controlling the refractive indices of the ring resonators 0 (37a) and the ring resonators (137b) of the CRR. Phase oscillation is used to select the oscillation wavelength of the laser diode.

The operation principle and characteristic simulation results of the CRR shown in the embodiment of FIG. 3 will now be described. In CRR, two ring resonators are coupled to each other, and these ring resonators are coupled to a straight waveguide. The light waves incident on the left side of the linear waveguide are combined into the ring resonator 0 (37a) on the left side to form light waves in the clockwise direction, and the light waves are combined into the ring resonator 1 (37b) on the right side to form light waves in the counterclockwise direction. . The optical wave is coupled to the linear waveguide so that the reverse wave travels in the linear waveguide 37c. In particular, by slightly varying the circumferential lengths of the two ring resonators, the free spectral range (FSR) of the two ring resonators is slightly different. In such a structure, if the effective refractive index of one ring resonator is adjusted little by little, strong reflection occurs only at the wavelength at which the two resonators simultaneously resonate, so that the maximum reflectance wavelength can be selected. In other words, if the refractive index of one ring resonator is fixed and the refractive index of the other resonator is gradually increased or decreased, reflectance peaks appear sequentially at wavelengths that increase or decrease by one FSR. The selection range of the wavelength is given by Equation 1 below.

Λ ₀ is the center wavelength of the variable wavelength range, n _g is the group refractive index of the ring resonator, R ₀ and R ₁ is the radius of the ring resonator. When the center wavelength is 1550 nm, the group refractive index is 3.7, and the radius of the ring resonator is R ₀ = 50 µm and R ₁ = 52 µm, the wavelength variable range reaches 52 nm.

For some combinations of refractive indices, reflection spectra with wavelengths are shown in FIG. 4. The combination ratio between the coupling ratio κ ₀ and κ _in the ring resonator and a ring resonator 1 0 between the straight waveguide and the ring resonator is assumed to be 0.64 and 0.08, respectively. In FIG. 4A, it is assumed that R ₀ = R ₁ = 50 μm, and the effective refractive index n _eff0 of the ring resonator 0 and the effective refractive index n _eff1 of the ring resonator 1 are all 3.29. In this case, since the FSR of the two ring resonators is the same, it can be seen that a reflection peak occurs at a period of 2.17 nm which is an FSR. Here, the maximum reflectance is 0.86, which is less than 1, because the coupling ratio between the linear waveguide and the ring waveguide is 0.64, which is relatively large. On the other hand, if there is a loss of the optical waveguide, the reflectance is expected to decrease. In FIG. 3A, the reflectance when the waveguide loss is 3 dB / cm is shown as a dotted line, and the peak reflectance decreases to 0.63. 4B, 4C, and 4D show reflectances when the two ring resonators have slightly different radii, that is, when R ₀ = 50 μm and R ₁ = 52 μm. The reflection spectra when the refractive index of the ring resonator 0 is fixed to 3.29 and the refractive indices of the ring resonator 1 are set to 3.29 + 1.9x10 ^-4 , 3.29 + 3.8x10 ^-4 , and 3.29 + 5.7x10 ^-4 are illustrated in FIGS. 4B, 4C, and 4D. Respectively. It can be seen that the wavelengths corresponding to the reflection peaks are sequentially selected such as 1.587746 μm, 1.589918 μm, and 1.5921 μm, respectively. It can be seen that the interval between sequentially selected wavelengths is 2.17 nm, which is equivalent to the FSR of the ring resonator 0.

Reflective properties such as FIGS. 4B, 4C and 4D are suitable for use as the wavelength selection element of a wideband tunable CRR laser diode. When the CRR having different radii is applied to the wideband tunable laser diode shown in FIG. 3, the characteristics of the laser diode are predicted. Consider a case where the ring resonator 0 has a refractive index of 3.29 and a radius of 50 μm, the ring resonator 1 has a refractive index of 3.29 + 1.9 × 10 ⁻⁴ and a radius of ⁵² μm. In this case, the shape of the reflection spectrum of the CRR is as shown in FIG. 4B.

To investigate the single longitudinal mode operation, the side mode suppression of the adjacent mode and the ring mode suppressor of the ring resonator mode should be investigated. To determine the mode spacing of the laser resonator, the effective length of the CRR must be taken into account. The effective length of CRR is shown in Equation 2.

Assuming the above-mentioned parameters, the effective length of the CRR is calculated to be about 4260 μm, which is much longer than that of a typical laser diode resonator. Where φ is the phase of the reflection coefficient and β is the propagation constant of the waveguide. Therefore, if the length of the active region (l _g ) is assumed to be 400μm, the mode interval of the laser resonator is calculated to be about 0.16 nm. In FIG. 3B, the reflection peak value is 0.83 and the reflectance at a wavelength 0.16 nm apart is 0.132. The loss margin for the adjacent sub mode can be expressed as Equation 3 below.

Wherein _(R R R _{L) 0} and _(R R R _{L) 1} is multiplied by the power reflectivity of the portion close to the main mode, each mode and l _g is the length of the gain active region. Calculating the loss margin for the negative mode of the adjacent laser resonator mode is equal to Δαg _g = 0.94. Using this value and the formula below, you can get a large 58 dB value by calculating the Side Mode Suppression Ratio (SMSR).

Where Γ is the confinement factor, g _th is the gain factor at critical conditions, υ _g is the group velocity, and α _m is the mirror loss for the main mode. Assuming that the laser output power P ₀ is 4 mW, the waveguide loss (α _act ) of the active region is 30 cm ⁻¹ , the length of the active region is 400 μm, and Γ g _th = (α _act + α _m ) l _g .

Consider the case of FIG. 4B again to estimate the negative mode suppression rate for the adjacent ring mode of the CRR. In this particular case, the resonant wavelengths of the two ring resonators are coincident with λ = 1,587746 μm at which the reflectance R _R is 0.86. At λ = 1,587746μm, the reflectance decreases by 0.68 at a wavelength separated by one FSR. Therefore, the loss margin for adjacent ring mode is about 0.11 and SMSR is about 49dB. In order to increase the SMSR while maintaining the tunable range, the coupling ratio between the linear waveguide and the ring resonator must be smaller to narrow the line width of the reflection spectrum. On the other hand, since the effective length of the CRR is as long as 4000μm, the line width of the wideband tunable CRR laser diode proposed in the present invention can be 1 MHz or less. Since the wavelength variable range of the CRR reaches 52 nm, the wavelength variable range of the laser diode employing the specific parameter CRR presented herein may also reach 52 nm.

In addition, by using a CRR structure on one side of the laser resonator and a reflecting surface on which the other side is cut off, the optical power output from the cut off reflective surface can be adjusted relatively large to obtain a high output wavelength tunable laser diode. . In addition, various types of modulators, amplifiers, optical filters, and the like can be integrated in the CRR output terminal of the laser diode, thereby realizing a high-performance optical integrated circuit.

Meanwhile, although the circular waveguide is shown as a ring resonator in the CRR structure of FIG. 3, the structure of the ring resonator is not limited to the circular waveguide, and a polygonal structure such as a triangular structure (FIG. 5) or a triangular structure including a total reflection mirror therein may be used. It may be.

 (Example 2)

6 is a perspective view illustrating a second embodiment of the present invention. The difference from FIG. 3 is that the CRR portions 60, 61a, 61b, 61c, 66a, 66b, 66c, 67a, 67b, 67c are realized using a material such as silica or polymer, and silica or polymer having CRR implemented. Broadband wavelength-variable CRR integrated as a hybrid, in which the Fabry-Perot laser diodes 62a, 62b, 62c, 64, 65 are aligned with the CRR linear waveguide in the etched area after proper etching of a part of It is to implement a laser diode. It is preferable that the left end face of the Fabry-Perot laser diode of FIG. 6 has reflection, and the right end face has an antireflective coating. It is preferable that the right end surface 63b of the CRR structure also has an antireflective coating. The CRR of FIG. 6 may also not necessarily have a circular structure, and may also have a rectangular structure including a total reflection mirror as shown in FIG. 5, furthermore, a triangular structure or a polygonal structure. In FIG. 6, the refractive index is controlled by thermo-optic or electro-optic effect by adjusting the current flowing through the refractive-index control electrodes 66a, 66b, 66c, or by applying an applied voltage, thereby selecting an oscillation wavelength by performing phase control. do.

 A simplified process is used by using a Coupled-Ring Reflector (CRR) instead of the Distributed Bragg Reflector (DBR), which causes wavelength selective reflection through optical power coupling between two ring resonators and a straight waveguide. Through the implementation of the CRR wideband tunable laser diode.

By using a CRR structure on one side of the laser resonator and a reflection surface cut off on the other side, a high output wavelength tunable laser diode can be obtained because the optical power output from the cut reflection surface can be relatively large.

The magnitude of the CRR reflectance can be adjusted by adjusting the coupling ratio.

Claims (15)

Photoamplification region; A pair of ring resonators capable of alternating optical power; A linear waveguide capable of alternating optical power with the ring resonator, And the pair of ring resonators and the linear waveguide form a coupled-ring reflector (CRR) to select the oscillation wavelength of the laser. The method of claim 1, The pair of ring resonators are wide-wavelength variable CRR laser diode, characterized in that the circumferential length is different from each other to vary the oscillation wavelength of the laser by the Vernier effect. The method of claim 1 A refractive index control electrode is formed in a portion of the ring resonator or an entire upper region of the ring resonator, and a refractive index control electrode is formed in a partial region or the entire upper region of the linear waveguide. The method of claim 3, wherein The refractive index control electrode is a wideband wavelength tunable CRR laser diode, characterized in that for changing the oscillation wavelength of the laser by changing the refractive index of the passive waveguide or the pair of ring resonator. Board; A multi-quantum well active layer and a passive waveguide layer formed adjacent to the n-type substrate; A cladding layer formed on the multi-quantum well active layer and the passive waveguide layer; An optical amplification region formed on the multi quantum well active layer; A pair of ring resonators, a phase control region, and a linear waveguide formed on the passive waveguide layer, The optical amplification area and the phase control area are formed on an extension line of the linear waveguide, The linear waveguide and the pair of ring resonators are combined and formed to exchange optical power to form CRR, And a refractive index control electrode is formed in part or the entire region of the pair of ring resonators and the linear waveguide. The method of claim 5, The pair of ring resonators are wide-wavelength variable CRR laser diode, characterized in that the circumferential length is different from each other to vary the oscillation wavelength of the laser by the Vernier effect. The method of claim 5, And the substrate is an n-type InP semiconductor, the passive waveguide layer is an InGaAsP-based semiconductor layer, and the clad layer is a p-type InP semiconductor layer.  The method of claim 5, The refractive index control electrode is a wideband wavelength tunable CRR laser diode, characterized in that for changing the oscillation wavelength of the laser by changing the refractive index of the passive waveguide or the pair of ring resonator. The method according to any one of claims 1 to 6 and 8 to 9, The pair of ring resonators are triangular, rectangular or polygonal structure, and a wideband wavelength variable CRR laser diode, characterized in that it includes a total reflection mirror therein. An optical amplification part formed in the form of an antireflection coated Fabry-Perot laser diode; A coupling ring reflector (CRR) consisting of a straight waveguide and a pair of ring resonators; The CRR is formed of silica or polymer; The optical amplifier and the CRR is a broadband wavelength tunable CRR laser diode, which is manufactured separately and integrated in a hybrid form on a silica or polymer substrate. delete delete delete delete delete

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