Ridge waveguide, high-performance CW laser epitaxial structure and preparation method thereof

Abstract

The invention provides a ridge waveguide, a high-performance CW laser epitaxial structure and a preparation method thereof, and belongs to the field of semiconductors. The ridge width range Wm of the main waveguide 101 is controlled to be 5-10 [mu] m, the ridge width range Wp of the passive waveguide 102 is controlled to be 1.5-5 [mu] m, a conical coupling area with a 0.8 [mu] m gap is constructed, single-mode output (the side mode suppression ratio is larger than 45 dB) under 500 mA injection current is achieved through mode selection resonance (Q value is larger than 1 * 10 < 4 >), and the power saturation threshold value is increased to 520 mA and is increased by 44% compared with a traditional single ridge waveguide (360 mA). The ridge waveguide provided by the invention also overcomes the defect of mode jump caused by insufficient gap control precision (+ / -0.1 mu m) of the existing double-ridge waveguide.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors, and in particular to a ridge waveguide, a high-performance CW laser epitaxial structure and a preparation method thereof. Background Art

[0002] As 400G / 800G optical modules evolve towards CPO packaging, the electro-absorption modulator of traditional EML lasers faces the bandwidth-chirp contradiction. The CW laser architecture based on silicon optical modulators has low transmission loss (<0.5dB / mm) and high modulation linearity (SFDR>110dB·Hz). 2 / 3 ) has become the mainstream solution for data center interconnection. However, this architecture has the following technical limitations: When the injection current exceeds 300mA (corresponding to an output power ≥200mW), the traditional transverse single-ridge waveguide suffers from uneven longitudinal carrier distribution (measured fluctuation >35%), leading to spatial hole burning, which brings the power saturation threshold forward to 360mA (a 40% reduction). Simultaneously, a surge in high-order transverse modes causes a double-peaked near-field light spot distortion (mode suppression ratio <20dB). Summary of the Invention

[0003] The present invention provides a ridge waveguide, a high-performance CW laser epitaxial structure and a preparation method thereof. The ridge waveguide of the present invention can improve the side mode suppression ratio and the power saturation threshold of the CW laser epitaxial structure.

[0004] The present invention provides a ridge waveguide, comprising a main waveguide 101 and a passive waveguide 102;

[0005] The main waveguide 101 includes a first P-InP buffer layer 010-1, a first P-InGaAsP grating layer 011-1, a first P-InP grating buried layer 012-1, a first P-InP connecting layer 013-1, a first P-InGaAsP barrier graded layer 014-1, a first P-InGaAsP barrier graded layer 015-1, and a first P-InGaAs ohmic contact layer 016-1 stacked in sequence;

[0006] The passive waveguide 102 includes a second P-InP buffer layer 010-2, a second P-InGaAsP grating layer 011-2, a second P-InP grating buried layer 012-2, a second P-InP connecting layer 013-2, a second P-InGaAsP barrier graded layer 014-2, a second P-InGaAsP barrier graded layer 015-2, and a second P-InGaAs ohmic contact layer 016-2 stacked in sequence;

[0007] The ridge width Wm of the main waveguide 101 is in the range of 5 to 10 μm, and the ridge width Wp of the passive waveguide 102 is in the range of 1.5 to 5 μm; the distance S between the main waveguide 101 and the passive waveguide 102 is in the range of 2 to 6 μm.

[0008] Preferably, the thickness of the first P-InP buffer layer 010 - 1 and the second P-InP buffer layer 010 - 2 are independently 80±2.4 nm;

[0009] The thickness of the first P-InGaAsP grating layer 011-1 and the second P-InGaAsP grating layer 011-2 are independently 30±0.9 nm, and the period of the grating patterns in the first P-InGaAsP grating layer 011-1 and the second P-InGaAsP grating layer 011-2 is 202 nm;

[0010] The thickness of the first P-InP grating buried layer 012-1 and the second P-InP grating buried layer 012-2 are independently 300±9nm, and the Zn doping concentration is independently 1-2×10 18 cm -3 ;

[0011] The thickness of the second P-InP connection layer 013 - 1 and the second P-InP connection layer 013 - 2 is 300±9 nm;

[0012] The thicknesses of the first P-InGaAsP barrier graded layer 014-1, the second P-InGaAsP barrier graded layer 014-2, the first P-InGaAsP barrier graded layer 015-1, and the second P-InGaAsP barrier graded layer 015-2 are independently 50±1.5 nm, and the Zn doping concentration increases from 1×10 18 cm -3 Increase to 5×10 19 cm -3 ;

[0013] The thickness of the first P-InGaAs ohmic contact layer 016-1 and the second P-InGaAs ohmic contact layer 016-2 are independently 200±6nm, and the Zn doping concentration is independently 3-5×10 19 cm -3 .

[0014] The present invention also provides a high-performance CW laser epitaxial structure, comprising a base metal layer, an N-type InP substrate 001, an N-InP buffer layer 002, an N-InGaAsP extended waveguide layer 003, an N-InP buffer layer 004, an N-InGaAsP lower confinement layer 005, an InGaAsP lower waveguide layer 006, an InGaAsP / InGaAsP quantum well active region 007, an InGaAsP upper waveguide layer 008, a P-InGaAsP upper confinement layer 009, and a ridge waveguide stacked in sequence; the ridge waveguide comprises the ridge waveguide according to claim 1 or 2;

[0015] The first P-InP buffer layer 010 - 1 is in contact with the P-InGaAsP upper confinement layer 009 ;

[0016] The second P-InP buffer layer 010 - 2 is in contact with the P-InGaAsP upper confinement layer 009 ;

[0017] Also includes:

[0018] An insulating layer and a p-electrode are in contact with and stacked with the first P-InGaAs ohmic contact layer 016-1 and the second P-InGaAs ohmic contact layer 016-2, wherein the insulating layer and the p-electrode surround the main waveguide 101 and the passive waveguide 102 and cover the structure between the main waveguide 101 and the passive waveguide 102; the p-electrode above the main waveguide 101 is connected to the P-InGaAs ohmic contact layer 016-1 via a connecting metal layer;

[0019] There is a through hole in the insulating layer above the main waveguide 101, and the connecting metal layer is embedded in the through hole.

[0020] Preferably, the composition of the N-InGaAsP extended waveguide layer 003 is In 1-x Ga x As y P 1-y ;

[0021] In the direction from the N-InP buffer layer 002 to the N-InP buffer layer 004 , x increases from 0.171 to 0.208, and y increases from 0.374 to 0.453.

[0022] Preferably, the thickness L of the N-InP buffer layer 004 is 1-2 μm.

[0023] Preferably, the p-electrode comprises a stacked Ti layer, a Pt layer and an Au layer; the p-electrode is embedded in the insulating layer; the bottom of the Ti layer is in contact with the insulating layer;

[0024] In the vertical direction, the p-electrode is circular in shape, and the diameter of the p-electrode is 65±1.95 μm.

[0025] Preferably, the thickness of the N-InP buffer layer 002 is 500 nm;

[0026] The thickness of the N-InGaAsP extended waveguide layer 003 is 15±0.45nm, the emission wavelength is 960-860nm, and the Si doping concentration is 1-2×10 18 cm -3 ;

[0027] The thickness of the N-InP buffer layer 004 is 1600±48nm, and the doping concentration is 2×10 18 cm -3 ;

[0028] The thickness of the N-InGaAsP lower confinement layer 005 is 100±3nm, the emission wavelength is 1000±10nm, and the Si doping concentration is 1-2×10 18 cm -3 ;

[0029] The thickness of the InGaAsP lower waveguide layer 006 is 50±1.5nm, and the emission wavelength is 1057±10nm;

[0030] The InGaAsP / InGaAsP quantum well active region 007 includes stacked quantum barrier layers and quantum well layers; the bottom and top of the InGaAsP / InGaAsP quantum well active region 007 are both quantum barrier layers; the number of quantum barrier layers is 6; the thickness of each quantum barrier layer is independently 10±0.3nm, and the emission wavelength is independently 1120±10nm; the thickness of each quantum well layer is independently 5±0.15nm, and the emission wavelength is independently 1120±10nm.

[0031] Preferably, the thickness of the InGaAsP upper waveguide layer 008 is 25±0.75 nm, and the emission wavelength is 1057±10 nm;

[0032] The thickness of the P-InGaAsP upper confinement layer 009 is 75±2.25nm, the emission wavelength is 1000±10nm, and the Zn doping concentration is 1-2×10 18 cm -3 .

[0033] The present invention also provides a method for preparing the high-performance CW laser epitaxial structure described in the above technical solution, comprising the following steps:

[0034] An N-InP buffer layer 002, an N-InGaAsP extended waveguide layer 003, an N-InP buffer layer 004, an N-InGaAsP lower confinement layer 005, an InGaAsP lower waveguide layer 006, an InGaAsP / InGaAsP quantum well active region 007, an InGaAsP upper waveguide layer 008, a P-InGaAsP upper confinement layer 009, a P-InP buffer layer, and a P-InGaAsP grating original layer are sequentially grown on an N-type InP substrate material;

[0035] Performing photolithography on the P-InGaAsP grating original layer to obtain a P-InGaAsP grating layer;

[0036] Depositing a P-InP grating buried layer, a P-InP connection layer, a first P-InGaAsP barrier graded layer, a second P-InGaAsP barrier graded layer and a P-InGaAs ohmic contact layer in sequence on the P-InGaAsP grating layer;

[0037] After coating the surface of the P-InGaAs ohmic contact layer with photoresist, performing exposure, development and etching using a mask, and then removing the remaining photoresist to form the main waveguide 101 and the passive waveguide 102;

[0038] Depositing a raw material for an insulating layer on the surfaces of the P-InGaAs ohmic contact layer 016-1, the P-InGaAs ohmic contact layer 016-2 and the P-InGaAsP upper confinement layer 009 to form an insulating layer;

[0039] After coating the surface of the insulating layer with photoresist, performing exposure, development, and etching using a mask, and then removing the remaining photoresist, a through hole is formed on the insulating layer between the p-electrode above the main waveguide 101 and the P-InGaAs ohmic contact layer 016-1;

[0040] Depositing metal in the through-hole to form a connecting metal layer;

[0041] After coating the surface of the insulating layer and the metal surface in the through hole of the connecting metal layer with photoresist, developing and etching are performed using a mask to form a p-electrode pattern on the surface of the insulating layer and the surface of the connecting metal layer, removing excess metal when forming the connecting metal layer, and then depositing a p-electrode raw material on the surface of the pattern to form the p-electrode;

[0042] After removing the remaining photoresist, the N-type InP substrate material is thinned to form the N-type InP substrate 001, and then the raw material of the base metal layer is deposited to form the base metal layer, thereby obtaining the high-performance CW laser epitaxial structure.

[0043] The present invention also provides a high-performance CW laser, comprising the high-performance CW laser epitaxial structure described in the above technical solution or the high-performance CW laser epitaxial structure prepared by the preparation method described in the above technical solution.

[0044] The present invention reduces the ridge width W of the main waveguide 101 to m The ridge width of the passive waveguide 102 is controlled within the range of 5 to 10 μm. p Controlled at 1.5~5μm, in resonance mode (Q value>1×10 4 ) achieved single-mode output (side mode suppression ratio > 45dB) under 500mA injection current, and the power saturation threshold was increased to 520mA, a 44% increase compared to the traditional single-ridge waveguide (360mA).

[0045] The double-ridge waveguide in the prior art achieves fundamental mode operation based on odd-even time symmetry. However, the double-ridge waveguide based on odd-even time symmetry requires electrodes to be made on each of the two ridges, and then current is applied to form a gain waveguide and a loss waveguide. In this case, the spacing between the two waveguides must be ensured to achieve electrical isolation. Therefore, in actual operation, it is necessary to simultaneously control the current and the spacing between the two waveguides to ensure that the high-order modes of the gain waveguide are coupled and eliminated by the loss waveguide as much as possible to achieve fundamental mode operation. The final result is usually affected by the spacing control problem. The present invention, based on the principle of coupled resonant cavity, only needs to inject current into the main waveguide, without considering the problem of electrical isolation. It breaks through the mode hopping defect caused by the insufficient gap control accuracy (±0.1μm) of the existing double-ridge waveguide and can obtain a more stable fundamental mode operating state.

[0046] Furthermore, the composition of the N-InGaAsP extended waveguide layer 003 of the present invention is In 1-x Ga x As y P 1-y From N-InP buffer layer 002 to N-InP buffer layer 004, x increases from 0.171 to 0.208, and y increases from 0.374 to 0.453, forming a high-refractive-contrast waveguide with Δn = 0.032 (conventional Δn = 0.018). This refractive-index gradient pulls the light field toward the n-region (offset 1.8μm), compressing θ to 28°±2°. Combined with the double-ridge waveguide lateral confinement, this reduces p-region hole scattering losses, increasing coupling efficiency to 75% (conventional 58%). This significantly reduces the insertion loss of the optical interconnect system by 3.2dB, and outperforms the existing fishbone lateral microstructure solution (coupling efficiency is only 65%). The synergistic optical field control technology of the ridge waveguide and the N-InGaAsP extended waveguide layer 003 achieves dual optimization of beam divergence angle compression and coupling efficiency improvement, ultimately resulting in higher beam quality.

[0047] The 5-10 μm ridge width design of the main waveguide of the present invention significantly increases the gain region area, achieving an optimized carrier concentration distribution at a high injection current of 500 mA. Combined with the synergistic heat dissipation of the p-electrode formed by the stacked Ti, Pt, and Au layers, the thermal resistance is reduced to 18.5 K / W (conventional > 30 K / W), and the high-temperature (85°C) saturation power is increased to 320 mW (a 26% increase over the conventional 254 mW), with a wavelength drift Δλ < 0.6 nm (conventional > 1.2 nm, meeting the 0.8 nm tolerance requirement of silicon waveguides). This breaks through the power-temperature mutual exclusion bottleneck caused by thermally induced mode hopping in traditional wide-ridge waveguides. Compared with the existing thermal management solution of quasi-PT symmetrical double-ridge waveguides (high-temperature power attenuation rate > 20%), the present invention achieves a 40% improvement in high-temperature power stability through grid-based heat dissipation path optimization.

[0048] The coordinated design of the metal grid heat dissipation of the P electrode and the optical field control of the N-InGaAsP extended waveguide layer 003 enables high power (320mW) and high beam quality (M 2 =1.15) is simultaneously achieved at 85°C, with a power attenuation rate reduced by 40% compared to existing solutions, meeting the stringent requirements of CPO packaging for laser wavelength stability (Δλ / nm / °C < 0.008) and optical module coupling tolerance (±0.1μm) under high-temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the epitaxial structure of embodiments 1 to 3 of the present invention;

[0050] Figure 2 This is a schematic diagram of the structure formed after the first epitaxial growth of the embodiment;

[0051] Figure 3 This is a schematic diagram of the structure formed after the second epitaxial growth of the embodiment;

[0052] Figure 4 The high-temperature saturation current and saturation power results of the epitaxial structures obtained in Comparative Example 1 and Example 1 are shown;

[0053] Figure 5 This is the light field of the epitaxial structure (normal structure) of Comparative Example 1;

[0054] Figure 6 This is the light field of the epitaxial structure of Example 1 (optimized structure 1);

[0055] Figure 7 : is the far-field divergence angle (y direction) of the epitaxial structure of comparative example 1 (normal structure) and the epitaxial structure of embodiment 1 (optimized structure 1);

[0056] Figure 8 Light field of the epitaxial structure of Example 2 (optimized structure 2);

[0057] Figure 9 : is the far-field divergence angle (y direction) of the epitaxial structure of comparative example 1 (normal structure) and the epitaxial structure of embodiment 2 (optimized structure 2);

[0058] Figure 10 Light field of the epitaxial structure of Example 3 (optimized structure 3);

[0059] Figure 11 : is the far-field divergence angle (y direction) of the epitaxial structure of comparative example 1 (normal structure) and the epitaxial structure of embodiment 3 (optimized structure 3);

[0060] Figure 12 Schematic diagram of the epitaxial structure of comparative example 1. DETAILED DESCRIPTION

[0061] The present invention provides a ridge waveguide, comprising a main waveguide 101 and a passive waveguide 102;

[0062] The main waveguide 101 includes a first P-InP buffer layer 010-1, a first P-InGaAsP grating layer 011-1, a first P-InP grating buried layer 012-1, a first P-InP connecting layer 013-1, a first P-InGaAsP barrier graded layer 014-1, a first P-InGaAsP barrier graded layer 015-1, and a first P-InGaAs ohmic contact layer 016-1 stacked in sequence;

[0063] The passive waveguide 102 includes a second P-InP buffer layer 010-2, a second P-InGaAsP grating layer 011-2, a second P-InP grating buried layer 012-2, a second P-InP connecting layer 013-2, a second P-InGaAsP barrier graded layer 014-2, a second P-InGaAsP barrier graded layer 015-2, and a second P-InGaAs ohmic contact layer 016-2 stacked in sequence;

[0064] The ridge width Wm of the main waveguide 101 is in the range of 5 to 10 μm, and the ridge width Wp of the passive waveguide 102 is in the range of 1.5 to 5 μm; the distance S between the main waveguide 101 and the passive waveguide 102 is in the range of 2 to 6 μm.

[0065] In the present invention, the ridge width range W of the main waveguide 101 is m is 5 to 10 μm. In a specific embodiment of the present invention, the ridge width range W of the main waveguide 101 is m Can be 5μm, 6μm, 7μm, 8μm, 9μm or 10μm;

[0066] The main waveguide 101 provided by the present invention includes a first P-InP buffer layer 010-1, and the thickness of the first P-InP buffer layer 010-1 is preferably 80±2.4 nm;

[0067] The main waveguide 101 provided by the present invention includes a first P-InGaAsP grating layer 011-1 on the surface of a first P-InP buffer layer 010-1; the thickness of the first P-InGaAsP grating layer 011-1 is preferably 30±0.9 nm, and the period of the grating pattern in the first P-InGaAsP grating layer 011-1 is preferably 202 nm;

[0068] The main waveguide 101 provided by the present invention includes a first P-InP grating buried layer 012-1 on the surface of the first P-InGaAsP grating layer 011-1; the thickness of the first P-InP grating buried layer 012-1 is preferably 300±9nm, and the Zn doping concentration is preferably 1-2×10 18 cm -3 ;

[0069] The main waveguide 101 provided by the present invention includes a first P-InP connection layer 013-1 on the surface of the first P-InP grating buried layer 012-1; the thickness of the first P-InP connection layer 013-1 is preferably 300±9 nm;

[0070] The main waveguide 101 provided by the present invention includes a first P-InGaAsP barrier gradient layer 014-1 on the surface of the first P-InP coupling layer 013-1; the thickness of the first P-InGaAsP barrier gradient layer 014-1 is preferably 50±1.5 nm;

[0071] The main waveguide 101 provided by the present invention includes a first P-InGaAsP barrier gradient layer 015-1 on the surface of the first P-InGaAsP barrier gradient layer 014-1; the thickness of the first P-InGaAsP barrier gradient layer 015-1 is preferably 50±1.5 nm;

[0072] In the present invention, the Zn doping concentration is preferably increased from 1×10 18 cm -3 Increase to 5×10 19 cm -3 ;

[0073] The main waveguide 101 provided by the present invention includes a first P-InGaAs ohmic contact layer 016-1 on the surface of the first P-InGaAsP barrier gradient layer 015-1; the thickness of the first P-InGaAs ohmic contact layer 016-1 is preferably 200 nm, and the Zn doping concentration is preferably 3 to 5×10 19 cm -3 .

[0074] In the present invention, the ridge width range W of the passive waveguide 102 is p is 1.5 to 5 μm. In a specific embodiment of the present invention, the ridge width range W of the passive waveguide 102 is m It may be 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm or 5 μm.

[0075] In the present invention, the parameters of the second P-InP buffer layer 010-2, the second P-InGaAsP grating layer 011-2, the second P-InP grating buried layer 012-2, the second P-InP connection layer 013-2, the first P-InGaAsP barrier graded layer 014-2, the second P-InGaAsP barrier graded layer 015-2, and the second P-InGaAs ohmic contact layer 016-2 in the passive waveguide 102 are as follows: Preferably, the parameters of the first P-InP buffer layer 010-1, the first P-InGaAsP grating layer 011-1, the first P-InP grating buried layer 012-1, the first P-InP connection layer 013-1, the first P-InGaAsP barrier graded layer 014-1, the second P-InGaAsP barrier graded layer 015-1, and the first P-InGaAs ohmic contact layer 016-1 are independently consistent, and are not repeated here;

[0076] In the present invention, the distance S between the main waveguide 101 and the passive waveguide 102 is 2 to 6 μm. In a specific embodiment of the present invention, the distance S between the main waveguide 101 and the passive waveguide 102 can be 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm or 6 μm.

[0077] The present invention also provides a high-performance CW laser epitaxial structure, comprising a base metal layer, an N-type InP substrate 001, an N-InP buffer layer 002, an N-InGaAsP extended waveguide layer 003, an N-InP buffer layer 004, an N-InGaAsP lower confinement layer 005, an InGaAsP lower waveguide layer 006, an InGaAsP / InGaAsP quantum well active region 007, an InGaAsP upper waveguide layer 008, a P-InGaAsP upper confinement layer 009, and a ridge waveguide stacked in sequence; the ridge waveguide comprises the ridge waveguide according to claim 1;

[0078] The first P-InP buffer layer 010 - 1 is in contact with the P-InGaAsP upper confinement layer 009 ;

[0079] The second P-InP buffer layer 010 - 2 is in contact with the P-InGaAsP upper confinement layer 009 ;

[0080] Also includes:

[0081] An insulating layer and a p-electrode are in contact with and stacked with the first P-InGaAs ohmic contact layer 016-1 and the second P-InGaAs ohmic contact layer 016-2, wherein the insulating layer and the p-electrode surround the main waveguide 101 and the passive waveguide 102 and cover the structure between the main waveguide 101 and the passive waveguide 102; the p-electrode above the main waveguide 101 is connected to the first P-InGaAs ohmic contact layer 016-1 via a connecting metal layer;

[0082] There is a through hole in the insulating layer above the main waveguide 101, and the connecting metal layer is embedded in the through hole.

[0083] The high-performance CW laser epitaxial structure provided by the present invention comprises a base metal layer.

[0084] The high-performance CW laser epitaxial structure provided by the present invention includes an N-type InP substrate 001 on the surface of a base metal layer.

[0085] The high-performance CW laser epitaxial structure provided by the present invention includes an N-InP buffer layer 002 on the surface of an N-type InP substrate 001. The thickness of the N-InP buffer layer 002 is preferably 500 nm. The N-InP buffer layer 002 is used to improve the flatness of the substrate surface.

[0086] The high performance CW laser epitaxial structure provided by the present invention comprises an N-InGaAsP extended waveguide layer 003 on the surface of an N-InP buffer layer 002, wherein the composition of the N-InGaAsP extended waveguide layer 003 is preferably In 1-x Ga x As y P 1-y In the direction from the N-InP buffer layer 002 to the N-InP buffer layer 004, x preferably increases from 0.171 to 0.208, and y preferably increases from 0.374 to 0.453; the thickness of the N-InGaAsP extended waveguide layer 003 is preferably 15±0.45nm, the emission wavelength is preferably 960~860nm, and the Si doping concentration is preferably 1~2×10 18 cm -3 .

[0087] The high-performance CW laser epitaxial structure provided by the present invention includes an N-InP buffer layer 004 on the surface of an N-InGaAsP extended waveguide layer 003. The thickness L of the N-InP buffer layer 004 is preferably 1 to 2 μm. The thickness of the N-InP buffer layer 004 is preferably 1600±48 nm, and the Si doping concentration is preferably 1 to 2×10 18 cm -3 .

[0088] The high-performance CW laser epitaxial structure provided by the present invention includes an N-InGaAsP lower confinement layer 005 on the surface of an N-InP buffer layer 004. The thickness of the N-InGaAsP lower confinement layer 005 is preferably 100±3nm, the emission wavelength is preferably 1000±10nm, and the Si doping concentration is preferably 1×10 18 cm -3 .

[0089] The high-performance CW laser epitaxial structure provided by the present invention includes an InGaAsP lower waveguide layer 006 on the surface of an N-InGaAsP lower confinement layer 005. The thickness of the InGaAsP lower waveguide layer 006 is preferably 50±1.5 nm, and the emission wavelength is preferably 1057±10 nm.

[0090] The high-performance CW laser epitaxial structure provided by the present invention includes an InGaAsP / InGaAsP quantum well active region 007 on the surface of an InGaAsP lower waveguide layer 006, wherein the InGaAsP / InGaAsP quantum well active region 007 includes stacked quantum barrier layers and quantum well layers; the bottom and top of the InGaAsP / InGaAsP quantum well active region 007 are both quantum barrier layers; the number of quantum barrier layers is 6; the thickness of the quantum barrier layers is preferably independently 10±0.3 nm, and the emission wavelength is preferably independently 1120±10 nm; the thickness of the quantum well layers is preferably independently 5±0.15 nm, and the emission wavelength is preferably independently 1120±10 nm.

[0091] The high-performance CW laser epitaxial structure provided by the present invention includes an InGaAsP upper waveguide layer 008 on the surface of an InGaAsP / InGaAsP quantum well active region 007. The thickness of the InGaAsP upper waveguide layer 008 is preferably 25±0.75 nm, and the emission wavelength is preferably 1057±10 nm.

[0092] The high-performance CW laser epitaxial structure provided by the present invention includes a P-InGaAsP upper confinement layer 009 on the surface of an InGaAsP upper waveguide layer 008. The thickness of the P-InGaAsP upper confinement layer 009 is preferably 75±2.25nm, the emission wavelength is preferably 1000±10nm, and the Zn doping concentration is preferably 1-2×10 18 cm -3 .

[0093] The high-performance CW laser epitaxial structure provided by the present invention includes a ridge waveguide on the surface of the InGaAsP upper waveguide layer 008; the P-InP buffer layer 010-1 contacts the P-InGaAsP upper confinement layer 009; and the P-InP buffer layer 010-2 contacts the P-InGaAsP upper confinement layer 009.

[0094] The high-performance CW laser epitaxial structure provided by the present invention also includes: an insulating layer and a p-electrode that are in contact with and stacked with the P-InGaAs ohmic contact layer 016-1 and the P-InGaAs ohmic contact layer 016-2, wherein the insulating layer and the p-electrode surround the main waveguide 101 and the passive waveguide 102 and cover the structure between the main waveguide 101 and the passive waveguide 102; the p-electrode above the main waveguide 101 is connected to the P-InGaAs ohmic contact layer 016-1 via a connecting metal layer; and the connecting metal layer is embedded in the insulating layer above the main waveguide 101.

[0095] In the present invention, the p-electrode preferably includes a stacked Ti layer, a Pt layer and an Au layer; the p-electrode is preferably embedded in the insulating layer; the p-electrode is preferably a grid structure, and the diameter of the grid in the p-electrode is preferably 65±1.95 μm.

[0096] The present invention also provides a method for preparing the high-performance CW laser epitaxial structure described in the above technical solution, comprising the following steps:

[0097] On an N-type InP substrate 001, an N-InP buffer layer 002, an N-InGaAsP extended waveguide layer 003, an N-InP buffer layer 004, an N-InGaAsP lower confinement layer 005, an InGaAsP lower waveguide layer 006, an InGaAsP / InGaAsP quantum well active region 007, an InGaAsP upper waveguide layer 008, a P-InGaAsP upper confinement layer 009, a P-InP buffer layer, and a P-InGaAsP grating original layer are sequentially grown;

[0098] Performing photolithography on the P-InGaAsP grating original layer to obtain a P-InGaAsP grating layer;

[0099] Depositing a P-InP grating buried layer, a P-InP connection layer, a first P-InGaAsP barrier graded layer, a second P-InGaAsP barrier graded layer and a P-InGaAs ohmic contact layer in sequence on the P-InGaAsP grating layer;

[0100] After coating the surface of the P-InGaAs ohmic contact layer with photoresist, performing exposure, development and etching using a mask, and then removing the remaining photoresist to form the main waveguide 101 and the passive waveguide 102;

[0101] Depositing a raw material for an insulating layer on the surfaces of the P-InGaAs ohmic contact layer 016-1, the P-InGaAs ohmic contact layer 016-2 and the P-InGaAsP upper confinement layer 009 to form an insulating layer;

[0102] After coating the surface of the insulating layer with photoresist, the insulating layer is exposed, developed, and etched using a mask, and then the remaining photoresist is removed to form a through hole between the p-electrode above the main waveguide 101 and the P-InGaAs ohmic contact layer 016-1 on the insulating layer;

[0103] Depositing metal in the through-hole to form a connecting metal layer;

[0104] After coating the surface of the insulating layer and the metal surface in the through hole of the connecting metal layer with photoresist, developing and etching are performed using a mask to form a p-electrode pattern on the surface of the insulating layer and the surface of the connecting metal layer, removing excess metal when forming the connecting metal layer, and then depositing a p-electrode raw material on the surface of the pattern to form the p-electrode;

[0105] After removing the remaining photoresist, the N-type InP substrate material is thinned to form the N-type InP substrate 001, and then the raw material of the base metal layer is deposited to form the base metal layer, thereby obtaining the high-performance CW laser epitaxial structure.

[0106] The present invention also provides a high-performance CW laser, comprising the high-performance CW laser epitaxial structure described in the above technical solution or the high-performance CW laser epitaxial structure prepared by the preparation method described in the above technical solution.

[0107] The ridge waveguide, high-performance CW laser epitaxial structure and preparation method thereof provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0108] Figure 1 Schematic diagrams of the epitaxial structures of embodiments 1 to 3 of the present invention.

[0109] Preparation method of epitaxial structure in Examples 1 to 3 and Comparative Example 1:

[0110] First epitaxial growth:

[0111] Process conditions: MOCVD equipment, substrate: N-InP 001 (length: 600±18μm, width: 250±7.5μm);

[0112] The growth order is:

[0113] N-InP buffer layer 002: 500nm thick, used to improve substrate surface flatness, emission wavelength is 917nm;

[0114] N-InGaAsP extended waveguide layer 003: thickness 15nm, emission wavelength 960~860nm, Si doping concentration 2×10 18 cm -3 The composition of the N-InGaAsP extended waveguide layer (003) is In1-x Ga x As y P 1-y ; In the direction from the N-InP buffer layer (002) to the N-InP buffer layer (004), x increases from 0.171 to 0.208, and y increases from 0.374 to 0.453.

[0115] N-InP buffer layer 004: thickness 1600nm, Si doping concentration 2×10 18 cm -3 , the emission wavelength is 917nm;

[0116] N-InGaAsP lower confinement layer 005: thickness 100nm, emission wavelength 1000nm, doping concentration 1×10 18 cm -3 ;

[0117] InGaAsP lower waveguide layer 006: thickness 50nm, emission wavelength 1057nm;

[0118] InGaAsP / InGaAsP quantum well active region 007: both the bottom and the top are quantum barrier layers; the number of quantum barrier layers is 6, the thickness of the quantum barrier layers is 10nm, the emission wavelength is 1120nm, the thickness of the quantum well layer is 5nm, and the emission wavelength is 1120nm.

[0119] InGaAsP upper waveguide layer 008: thickness 25nm, emission wavelength 1057nm;

[0120] P-InGaAsP upper confinement layer 009: thickness 75nm, emission wavelength 1000nm, Zn doping concentration 1×10 18 cm -3 ;

[0121] P-InP buffer layer 010: thickness 80nm, emission wavelength 917nm;

[0122] P-InGaAsP grating layer 011: 30nm thick, used to form a distributed feedback DFB grating with an emission wavelength of 1150nm;

[0123] The schematic diagram of the structure formed after the first epitaxy is as follows Figure 2 shown.

[0124] Second epitaxial grating buried layer preparation

[0125] Photolithography process: holographic exposure or electron beam exposure is used to produce a grating pattern with a period of 202nm on the surface of the grating layer 011;

[0126] Epitaxial growth:

[0127] P-InP grating buried layer 012: pulsed deposition method, thickness 300nm, Zn doping concentration 1×10 18 cm -3 ; Completely cover the grating structure;

[0128] P-InP connection layer 013: thickness 300nm, emission wavelength 917nm;

[0129] P-InGaAsP barrier graded layers 014 and 015: The two layers are 50nm each, with a Zn gradient doping concentration from 1×10 18 cm -3 to 5×10 19 cm -3 ;

[0130] P-InGaAs ohmic contact layer 016: thickness 200nm, Zn doping concentration 5×10 19 cm -3 , reducing contact resistance.

[0131] The schematic diagram of the structure formed after the second epitaxy is as follows Figure 3 shown.

[0132] Ridge waveguide fabrication

[0133] 1. Photoresist deposition: The structure formed after the second epitaxy is cleaned and fixed on the turntable of the spin coater. The photoresist is evenly coated on the surface of the P-InGaAs ohmic contact layer 016 in liquid form;

[0134] 2. Photoresist patterning: After coating, the wafer will undergo a soft bake to remove the solvent in the photoresist and make it more stable. Before the photoresist is cured, the wafer will be exposed to a UV light source to transfer the pattern of the double-ridge waveguide to the photoresist through a mask. After exposure, the wafer will be immersed in a developer to remove the unexposed photoresist (for positive photoresist) or the exposed photoresist (for negative photoresist) to form the desired pattern. After development is completed, the wafer is usually hard baked to enhance the mechanical strength and corrosion resistance of the photoresist in preparation for subsequent etching or deposition steps;

[0135] 3. Ridge etching: Use wet etching (freezing point bromine aqueous solution and freezing point HCl solution) to remove the material under the photoresist to form a ridge structure (i.e.: 10-1~16-1 and 10-2~16-2);

[0136] 4. Photoresist removal: remove the photoresist by chemical solvent;

[0137] 5. Oxide deposition: A SiO2 insulating layer is grown by PECVD to achieve electrical isolation between the p-electrode and the first P-InGaAs ohmic contact layer 16-1 and the second P-InGaAs ohmic contact layer 16-2, while reducing ridge waveguide surface defects (dangling bonds);

[0138] 6. Photoresist deposition: deposit photoresist again;

[0139] 7. Photoresist patterning: patterning again;

[0140] 8. Oxide etching: Etching the SiO2 insulating layer above the main waveguide 101 with a hydrofluoric acid solution to form a through hole;

[0141] 9. Photoresist removal: remove the photoresist again;

[0142] 10. Connection metal deposition: Ti, Pt and Au are deposited into the through-holes in sequence by magnetron sputtering or electroplating to form a connection metal layer;

[0143] 11. Photoresist deposition: deposit photoresist again;

[0144] 12. Photoresist patterning: Patterning is performed again, and the excess metal formed during the connection metal deposition in step 10 is removed by metal etching solution or HF solution to form a p-electrode pattern;

[0145] 13. P-type flexible metal deposition / patterning: Ti, Pt, and Au are deposited onto the p-type electrode pattern on the surface of the SiO2 insulating layer by magnetron sputtering or electroplating to form a p-type electrode (Ti layer thickness 60 nm; Pt layer thickness 60 nm; Au layer thickness 20 nm, and the p-type electrode diameter is 65 ± 1.95 μm);

[0146] 14. Photoresist removal: remove the remaining photoresist;

[0147] 15. Wafer thinning: Thin the substrate (about 120μm) through mechanical grinding;

[0148] 16. Metal deposition on the back of the wafer: Ti, Pt and Au are deposited on the wafer by magnetron sputtering or electroplating to form a base metal layer (Ti layer thickness 60nm; Pt layer thickness 60nm; Au layer thickness 20nm).

[0149] Example 1

[0150] Wm=7μm, Wp=3.5μm, S=2μm, L=1μm.

[0151] Comparative Example 1

[0152] The only difference from Example 1 is that Wm=1.3 μm.

[0153] Figure 12 Schematic diagram of the epitaxial structure of comparative example 1.

[0154] The high temperature saturation current and saturation power of the epitaxial structure obtained by software simulation of Comparative Example 1 and Example 1 are as follows: Figure 4 shown.

[0155] Depend on Figure 4 It can be seen that at 320K, the high-temperature saturation current of the waveguide with a ridge width of 1.3μm is about 230mA, and the saturation power is about 70mW; the high-temperature saturation current of the waveguide with a ridge width of 7.5μm is about 1000mA, and the saturation power is about 320mW.

[0156] Figure 5 This is the light field of the epitaxial structure (normal structure) of Comparative Example 1; Figure 6 This is the light field of the epitaxial structure of Example 1 (optimized structure 1).

[0157] like Figure 5 As shown in the figure, the traditional single-ridge waveguide lacks a mode selection mechanism, so its TE0 fundamental mode and TE1 first-order mode coexist (the power accounts for 62% and 38% respectively); while the double-ridge waveguide uses directional coupling with a 0.8μm tapered gap to connect the main waveguide TE1 mode with the passive auxiliary waveguide fundamental mode (Q>1×10 4 ) Resonance locking, using the loss characteristics of the passive auxiliary waveguide, the single-mode purity of the main waveguide is increased to 97% ( Figure 6 ).

[0158] Figure 7 2 is the far-field divergence angle (y direction) of the epitaxial structure of comparative example 1 (normal structure) and the epitaxial structure of embodiment 1 (optimized structure 1).

[0159] Depend on Figure 7 It can be seen that 1-x Ga x As y P 1-y The refractive index gradient of the graded expansion layer (x=0.171→0.208, y=0.374→0.453) works synergistically with the lateral confinement of the double-ridge waveguide to compress the far-field divergence angle in the y direction to 28°±2°, thereby improving the overall beam quality and significantly enhancing the fiber coupling efficiency and long-distance transmission stability.

[0160] Example 2

[0161] The only differences from Example 1 are: Wm=7.5 μm, Wp=4 μm, S=3.2 μm, and L=1.5 μm.

[0162] The optimized structure 2 under the above parameters is simulated by simulation software, and the simulation results are compared with the ordinary structure.

[0163] Figure 8 Light field of the epitaxial structure of Example 2 (optimized structure 2); Figure 9 2 is the far-field divergence angle (y direction) of the epitaxial structure of comparative example 1 (normal structure) and the epitaxial structure of embodiment 2 (optimized structure 2).

[0164] Depend on Figure 8 It can be seen that the high-order mode of the main waveguide is coupled to the passive waveguide. Since there is no current injection in the passive waveguide, the high-order mode is eventually lost, ensuring that the main waveguide operates in the fundamental mode.

[0165] Depend on Figure 9 It can be seen that the design of the present invention can obtain a smaller far-field divergence angle (20°±1°), and thus has better beam quality.

[0166] Example 3

[0167] The only differences from Example 1 are: Wm=9 μm, Wp=5 μm, S=4 μm, and L=2 μm.

[0168] The optimized structure 3 under the above parameters is simulated by simulation software, and the simulation results are compared with those of the ordinary structure.

[0169] Figure 10 Light field of the epitaxial structure of Example 3 (optimized structure 3); Figure 11 2 is the far-field divergence angle (y direction) of the epitaxial structure of comparative example 1 (normal structure) and the epitaxial structure of embodiment 3 (optimized structure 3).

[0170] Depend on Figure 10 It can be seen that the high-order mode of the main waveguide is coupled to the passive waveguide. Since there is no current injection in the passive waveguide, the high-order mode is eventually lost, ensuring that the main waveguide operates in the fundamental mode.

[0171] Depend on Figure 11 It can be seen that the design of the present invention can obtain a smaller far-field divergence angle (20°±1°), and thus has better beam quality.

[0172] When the propagation constants β=2πn / λ between the modes are close, the light fields will couple with each other. A 0.8μm tapered coupling region (light field) is constructed through the main / auxiliary waveguides (7μm / 3.5μm). 4 ) mode, the main waveguide high-order mode (TE1) is directionally coupled to the passive auxiliary waveguide fundamental mode, achieving a single-mode purity of >97% (side mode suppression ratio >45dB) under 500mA injection, which is 2.3 times more stable than the traditional single-ridge width waveguide (dual-mode coexistence, TE0 / TE1 power ratio of 62% / 38%).

[0173] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A ridge waveguide, characterized in that: It includes a main waveguide (101) and a passive waveguide (102); The main waveguide (101) comprises a first P-InP buffer layer (010-1), a first P-InGaAsP grating layer (011-1), a first P-InP grating buried layer (012-1), a first P-InP connection layer (013-1), a first P-InGaAsP barrier gradient layer (014-1), a first P-InGaAsP barrier gradient layer (015-1), and a first P-InGaAs ohmic contact layer (016-1) stacked in sequence; The passive waveguide (102) comprises a second P-InP buffer layer (010-2), a second P-InGaAsP grating layer (011-2), a second P-InP grating buried layer (012-2), a second P-InP connection layer (013-2), a second P-InGaAsP barrier gradient layer (014-2), a second P-InGaAsP barrier gradient layer (015-2), and a second P-InGaAs ohmic contact layer (016-2) stacked in sequence; The ridge width range W of the main waveguide (101) m The ridge width of the passive waveguide 102 is in the range of 5 to 10 μm. p The distance S between the main waveguide (101) and the passive waveguide 102 is 2 to 6 μm.

2. The ridge waveguide according to claim 1, wherein The thickness of the first P-InP buffer layer (010-1) and the second P-InP buffer layer (010-2) are independently 80±2.4 nm; The thickness of the first P-InGaAsP grating layer (011-1) and the second P-InGaAsP grating layer (011-2) are independently 30±0.9 nm, and the period of the grating patterns in the first P-InGaAsP grating layer (011-1) and the second P-InGaAsP grating layer (011-2) is 202 nm; The thickness of the first P-InP grating buried layer (012-1) and the second P-InP grating buried layer (012-2) are independently 300±9nm, and the Zn doping concentration is independently 1-2×10 18 cm -3 ; The thickness of the second P-InP connection layer (013-1) and the second P-InP connection layer (013-2) is 300±9nm; The thicknesses of the first P-InGaAsP barrier graded layer (014-1), the second P-InGaAsP barrier graded layer (014-2), the first P-InGaAsP barrier graded layer (015-1) and the second P-InGaAsP barrier graded layer (015-2) are independently 50±1.5 nm, and the Zn doping concentration increases from 1×10 18 cm -3 Increase to 5×10 19 cm -3 ; The thickness of the first P-InGaAs ohmic contact layer (016-1) and the second P-InGaAs ohmic contact layer (016-2) are independently 200±6nm, and the Zn doping concentration is independently 3 to 5×10 19 cm -3 .

3. A high-performance CW laser epitaxial structure, characterized in that: The invention comprises a base metal layer, an N-type InP substrate (001), an N-InP buffer layer (002), an N-InGaAsP extended waveguide layer (003), an N-InP buffer layer (004), an N-InGaAsP lower confinement layer (005), an InGaAsP lower waveguide layer (006), an InGaAsP / InGaAsP quantum well active region (007), an InGaAsP upper waveguide layer (008), a P-InGaAsP upper confinement layer (009) and a ridge waveguide stacked in sequence; the ridge waveguide comprises the ridge waveguide according to claim 1 or 2; The first P-InP buffer layer (010-1) is in contact with the P-InGaAsP upper confinement layer (009); The second P-InP buffer layer (010-2) is in contact with the P-InGaAsP upper confinement layer (009); Also includes: An insulating layer and a p-electrode are stacked and in contact with the first P-InGaAs ohmic contact layer (016-1) and the second P-InGaAs ohmic contact layer (016-2), wherein the insulating layer and the p-electrode surround the main waveguide (101) and the passive waveguide 102 and cover the structure between the main waveguide (101) and the passive waveguide 102; the p-electrode above the main waveguide (101) is connected to the P-InGaAs ohmic contact layer (016-1) via a connecting metal layer; There is a through hole in the insulating layer above the main waveguide (101), and the connecting metal layer is embedded in the through hole.

4. The high-performance CW laser epitaxial structure according to claim 3, characterized in that: The composition of the N-InGaAsP extended waveguide layer (003) is In 1-x Ga x As y P 1-y ; In the direction from the N-InP buffer layer (002) to the N-InP buffer layer (004), x increases from 0.171 to 0.208, and y increases from 0.374 to 0.

453.

5. The high-performance CW laser epitaxial structure according to claim 3, characterized in that: The thickness L of the N-InP buffer layer (004) is 1-2 μm.

6. The high-performance CW laser epitaxial structure according to claim 3, characterized in that: The p-electrode includes a stacked Ti layer, a Pt layer, and an Au layer; the p-electrode is embedded in the insulating layer; the bottom of the Ti layer is in contact with the insulating layer; In the vertical direction, the p-electrode is circular in shape, and the diameter of the p-electrode is 65±1.95 μm.

7. The high-performance CW laser epitaxial structure according to any one of claims 3 to 6, characterized in that: The thickness of the N-InP buffer layer (002) is 500 nm; The thickness of the N-InGaAsP extended waveguide layer (003) is 15±0.45nm, the emission wavelength is 960-860nm, and the Si doping concentration is 1-2×10 18 cm -3 ; The thickness of the N-InP buffer layer (004) is 1600±48nm, and the doping concentration is 2×10 18 cm -3 ; The thickness of the N-InGaAsP lower confinement layer (005) is 100±3nm, the emission wavelength is 1000±10nm, and the Si doping concentration is 1-2×10 18 cm -3 ; The thickness of the InGaAsP lower waveguide layer (006) is 50±1.5nm, and the emission wavelength is 1057±10nm; The InGaAsP / InGaAsP quantum well active region (007) comprises stacked quantum barrier layers and quantum well layers; the bottom and top of the InGaAsP / InGaAsP quantum well active region (007) are both quantum barrier layers; the number of quantum barrier layers is 6; the thickness of each quantum barrier layer is independently 10±0.3nm, and the emission wavelength is independently 1120±10nm; the thickness of each quantum well layer is independently 5±0.15nm, and the emission wavelength is independently 1120±10nm.

8. The high-performance CW laser epitaxial structure according to claim 7, characterized in that: The thickness of the InGaAsP upper waveguide layer (008) is 25±0.75nm, and the emission wavelength is 1057±10nm; The thickness of the P-InGaAsP upper confinement layer (009) is 75±2.25nm, the emission wavelength is 1000±10nm, and the Zn doping concentration is 1-2×10 18 cm -3 .

9. The method for preparing a high-performance CW laser epitaxial structure according to any one of claims 3 to 8, characterized in that: The following steps are involved: An N-InP buffer layer (002), an N-InGaAsP extended waveguide layer (003), an N-InP buffer layer (004), an N-InGaAsP lower confinement layer (005), an InGaAsP lower waveguide layer (006), an InGaAsP / InGaAsP quantum well active region (007), an InGaAsP upper waveguide layer (008), a P-InGaAsP upper confinement layer (009), a P-InP buffer layer, and a P-InGaAsP grating original layer are sequentially grown on an N-type InP substrate material; Performing photolithography on the P-InGaAsP grating original layer to obtain a P-InGaAsP grating layer; Depositing a P-InP grating buried layer, a P-InP connection layer, a first P-InGaAsP barrier graded layer, a second P-InGaAsP barrier graded layer and a P-InGaAs ohmic contact layer in sequence on the P-InGaAsP grating layer; After coating a photoresist on the surface of the P-InGaAs ohmic contact layer, performing exposure, development and etching using a mask, and then removing the remaining photoresist to form a main waveguide (101) and a passive waveguide (102); Depositing a raw material for an insulating layer on the surfaces of the P-InGaAs ohmic contact layer (016-1), the P-InGaAs ohmic contact layer (016-2) and the P-InGaAsP upper confinement layer (009) to form an insulating layer; After coating the surface of the insulating layer with photoresist, performing exposure, development and etching using a mask, and then removing the remaining photoresist, forming a through hole between the p-electrode above the main waveguide (101) and the P-InGaAs ohmic contact layer (016-1) on the insulating layer; Depositing metal in the through-hole to form a connecting metal layer; After coating the surface of the insulating layer and the metal surface in the through hole of the connecting metal layer with photoresist, developing and etching are performed using a mask to form a p-electrode pattern on the surface of the insulating layer and the surface of the connecting metal layer, removing excess metal when forming the connecting metal layer, and then depositing a p-electrode raw material on the surface of the pattern to form the p-electrode; After removing the remaining photoresist, the N-type InP substrate material is thinned to form an N-type InP substrate (001), and then the raw material of the base metal layer is deposited to form the base metal layer, thereby obtaining the high-performance CW laser epitaxial structure.

10. A high performance CW laser, characterized in that: The invention comprises the high-performance CW laser epitaxial structure according to any one of claims 2 to 8 or the high-performance CW laser epitaxial structure prepared by the preparation method according to claim 9.

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