CN117317802A - Multi-wavelength semiconductor laser and laser generation method - Google Patents

Abstract

The present disclosure provides a multi-wavelength semiconductor laser, which includes from bottom to top: N-surface electrode layer, substrate layer, buffer layer, lower waveguide layer, multi-quantum well active layer, upper waveguide layer, multi-wavelength grating layer, etching self- Stop layer, cladding layer, ohmic contact layer, and P-surface electrode layer; wherein parallel first channels and second channels are etched from the surface of the ohmic contact layer toward the substrate layer, and the first A ridge waveguide is formed between the channel and the second channel, and the first channel and the second channel have the same size. At the same time, the present disclosure also provides a laser generation method based on the above-mentioned multi-wavelength semiconductor laser.

Description

Multi-wavelength semiconductor laser and laser generation method

Technical field

The present disclosure relates to the technical field of semiconductor lasers, and in particular, to a multi-wavelength semiconductor laser and a laser generation method.

Background technique

Multi-wavelength laser light sources have broad application prospects and important scientific research value in fields such as fiber optic sensing, DWDM laser communications, spectral analysis, and nonlinear frequency conversion. At present, the multi-wavelength light implementation of semiconductor lasers mainly includes beam synthesis, external cavity and array laser solutions. Among them, beam synthesis mainly involves the spatial superposition of multiple beams of light with different wavelengths, and the output beam after synthesis is multi-wavelength. The external cavity solution is to design different diffractive optical elements, such as FP etalons, fiber gratings, etc., to form a mode selection structure. By reflecting laser light of a specific wavelength back into the inner cavity of the semiconductor laser, a mode competition is formed to select different wavelengths. However, there are common problems of complex structure, large size and high power consumption. Array lasers mainly use docking growth technology to obtain gain materials with different emission wavelengths on the same substrate to achieve multi-wavelength array output. Although the integration level is high, the manufacturing process requirements are high.

Contents of the invention

(1) Technical problems to be solved

Based on the above problems, the present disclosure provides a single-chip multi-wavelength semiconductor laser and laser generation method with compact structure, low power consumption and mature technology to alleviate the above technical problems in the existing technology.

(2) Technical solutions

One aspect of the present disclosure provides a multi-wavelength semiconductor laser, including from bottom to top: an N-plane electrode layer, a substrate layer, a buffer layer, a lower waveguide layer, a multi-quantum well active layer, an upper waveguide layer, and a multi-wavelength grating layer. , etching the self-stop layer, the cladding layer, the ohmic contact layer, and the P-surface electrode layer; wherein parallel first channels and second channels are etched from the surface of the ohmic contact layer toward the direction of the substrate layer, A ridge waveguide is formed between the first channel and the second channel, and the first channel and the second channel have the same size.

According to an embodiment of the present disclosure, the etching depths of the first channel and the second channel are the same, and the bottoms of the first channel and the second channel are above the etching self-stop layer.

According to an embodiment of the present disclosure, the width of the first channel and the third channel is 6 microns to 15 microns.

According to an embodiment of the present disclosure, the width of the ridge waveguide is 1.5 microns to 3 microns, and the height is 1.5 microns to 2.5 microns.

According to an embodiment of the present disclosure, the backlight surface of the ridge waveguide is coated with a high-reflective film, and the light-emitting surface is coated with an anti-reflection film.

According to an embodiment of the present disclosure, the high reflection film and the anti-reflection film have a refractive index of 1 to 3.

According to an embodiment of the present disclosure, the multi-wavelength grating layer is etched on the upper waveguide layer and is used for mode selection of laser light generated by a laser.

According to an embodiment of the present disclosure, multi-segment distributed feedback gratings with different grating constants and duty cycles are arranged in series in the multi-wavelength grating layer, and the multi-segment distributed feedback grating is used to generate multi-longitudinal mode laser lasing for the laser.

According to an embodiment of the present disclosure, the material of the substrate layer includes InP; the material of the buffer layer includes silicon-doped InP; the material of the lower waveguide layer includes silicon-doped InP, and the doping ratio is different from that of the buffer layer; The material of the multi-quantum well active layer includes InAlGaAs or InGaAsP; the material of the upper waveguide layer includes zinc-doped InP; the material of the etching self-stop layer includes Zn-doped InGaAsP; the material of the cladding layer includes Zn-doped InP, ohm The material of the contact layer includes Zn-doped InGaAs; the material of the P-surface electrode layer includes titanium and platinum; and the material of the N-surface electrode layer includes gold, germanium and nickel.

Another aspect of the present disclosure provides a laser generation method that generates laser based on the multi-wavelength semiconductor laser as described in any one of the above. The laser generation method includes: applying current pumping to the P-plane electrode layer of the laser. , so that the operating current of the ridge waveguide and the corresponding multi-quantum well active layer is above the threshold current, thus manifesting as energy gain to generate laser lasing; the multi-wavelength grating layer is arranged in series with different grating constants and duty cycles The multi-segment distributed feedback grating acts on the multi-quantum well active layer at the same time, so that the longitudinal mode mode of the laser is consistent with the multi-wavelength longitudinal mode mode of the multi-wavelength grating layer to produce multi-wavelength laser lasing.

(3) Beneficial effects

It can be seen from the above technical solutions that the multi-wavelength semiconductor laser and laser generation method of the present disclosure have at least one or part of the following beneficial effects:

(1) Introduce a variety of distributed Bragg feedback gratings with different grating periods and duty cycles in series, and work together with the multi-quantum well active layer to achieve multi-longitudinal mode mode selection and achieve stable and controllable multi-wavelength laser emission;

(2) It has the advantages of compact structure and low power consumption. It only needs one laser gain medium to achieve controllable multi-wavelength output;

(3) It is possible to achieve miniaturization and integration of multi-wavelength light sources in fiber-optic sensing systems, increasing the number of sensing array sources of the sensor while reducing volume and power consumption.

Description of drawings

Figure 1 schematically shows a three-dimensional structural diagram of a multi-wavelength semiconductor laser provided by an embodiment of the present disclosure;

Figure 2 schematically shows a front view of a multi-wavelength semiconductor laser shown in Figure 1 provided by an embodiment of the present disclosure;

Figure 3 schematically shows a top view of a multi-wavelength semiconductor laser shown in Figure 1 provided by an embodiment of the present disclosure;

Figure 4 schematically shows a side view of a multi-wavelength semiconductor laser shown in Figure 1 provided by an embodiment of the present disclosure;

FIG. 5 schematically shows the internal structure of the grating layer of the multi-wavelength semiconductor laser shown in FIG. 1 provided by an embodiment of the present disclosure;

Figure 6 schematically shows a multi-wavelength spectrum diagram of a multi-wavelength semiconductor laser shown in Figure 1 provided by an embodiment of the present disclosure;

Explanation of reference symbols:

1-N surface electrode layer; 2-substrate layer; 3-buffer layer; 4-lower waveguide layer; 5-multiple quantum well active layer; 6-upper waveguide layer; 7-multi-wavelength grating layer; 7.1-first grating Segment; 7.2-Second grating segment; 7.3-Third grating segment; 7.4-Fourth grating segment; 8-Etching self-stop layer; 9-cladding layer; 10-Ohm contact layer; 11-P surface electrode layer; 12 - first channel; 13 - ridge waveguide; 14 - second channel.

Detailed ways

The present disclosure provides a multi-wavelength semiconductor laser and a laser generation method. The multi-wavelength semiconductor laser includes, from bottom to top, an N-surface electrode layer, a substrate layer, a buffer layer, a lower waveguide layer, a multi-quantum well active layer, and an upper waveguide layer. , multi-wavelength grating layer, etching self-stop layer, cladding layer, ohmic contact layer, P-surface electrode layer, each layer is stacked in sequence; wherein, the laser is engraved in the direction from the surface of the ohmic contact layer to the substrate layer. A parallel first channel and a second channel are etched, a ridge waveguide is formed between the first channel and the second channel, and the first channel and the second channel have the same size. Current pumping is applied to the P-plane electrode layer of the laser, so that the operating current of the ridge waveguide and the corresponding multi-quantum well active layer is above its threshold current, which manifests as energy gain, and laser lasing can be generated; with this At the same time, the series of multi-segment distributed feedback gratings with different grating constants and duty ratios in the multi-wavelength grating layer act on the multi-quantum well active layer at the same time, so that the longitudinal mode mode of the lasing is the same as that in the multi-wavelength grating layer. The designed multi-wavelength longitudinal mode patterns are matched to produce multi-wavelength laser lasing.

In order to make the purpose, technical solutions and advantages of the present disclosure more clear, the present disclosure will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

In an embodiment of the present disclosure, a multi-wavelength semiconductor laser is provided. As shown in Figures 1-5, the multi-wavelength semiconductor laser includes: stacked in sequence from bottom to top:

N-surface electrode layer 1, substrate layer 2, buffer layer 3, lower waveguide layer 4, multiple quantum well active layer 5, upper waveguide layer 6, multi-wavelength grating layer 7, etching self-stop layer 8, cladding layer 9, ohm Contact layer 10 and P-surface electrode layer 11; wherein, parallel first channels 12 and second channels 14 are etched on the laser in a direction from the surface of the ohmic contact layer 10 to the substrate layer 2, so A ridge waveguide 13 is formed between the first channel 12 and the second channel 14, and the first channel 12 and the second channel 14 have the same size.

Among them, the N-surface electrode layer 1 is used to form an ohmic contact; the substrate layer 2 is used as a base for preparing other layers; the buffer layer 3 is used to buffer; the first waveguide layer 13 is used to limit the light field; the multi-quantum well has The source layer 5 is used to generate stimulated radiation of light; the second waveguide layer 14 is used to limit the light field; the multi-wavelength grating layer 7 is used to select multiple longitudinal modes; the etching self-stop layer 8 is used to control the etching depth; including Layer 9 is used to limit the light field and carrier diffusion; the ohmic contact layer 10 is used to form ohmic contact with the P-surface electrode layer 11.

In the embodiment of the present disclosure, a multi-wavelength grating layer 7 is etched on the upper waveguide layer 6 for mode selection of the laser light generated by the laser.

In the embodiment of the present disclosure, multi-segment distributed feedback gratings with different grating constants and duty cycles are arranged in series in the multi-wavelength grating layer 7 to generate multi-longitudinal mode laser lasing for the laser.

In the embodiment of the present disclosure, the multi-wavelength grating layer 7 of the laser is composed of a variety of distributed feedback gratings with different single-wavelength filters. As shown in Figure 5, the multi-wavelength grating layer 7 includes a first waveform with a wavelength of λ ₁ . The grating segment, the second grating segment 7.2 with the wavelength λ ₂ , the third grating segment 7.3 with the wavelength λ ₃ , and the fourth grating segment 7.4 with the wavelength λ ₄ are connected in series, and the multi-quantum well active layer 5 is Different periodic refractive index changes are generated internally, and multiple single-wavelength filtering effects are superimposed, as shown in Figure 6, so that the final filtered spectrum is multi-wavelength simultaneous filtering, completing multi-wavelength laser lasing. This structure has the advantages of compact structure and low power consumption. It only needs one laser gain medium to achieve controllable multi-wavelength output. Then, the miniaturization and integration of multi-wavelength light sources in the optical fiber sensing system can be achieved, increasing the number of sensing array sources of the sensor while reducing the size and power consumption.

In this embodiment, the multi-wavelength semiconductor laser has a cavity length of 1000 to 5000 microns and a width of 300 to 600 microns.

In the embodiment of the present disclosure, the etching depths of the first channel 12 and the second channel 14 are the same, and the bottom is above the etching stop layer 8 . The multi-wavelength grating layer 7 is obtained by holographic exposure or electron beam exposure.

In the embodiment of the present disclosure, as shown in Figures 1 and 2, the first channel 12 and the second channel 14 are etched to the top of the stop layer, and the formed ridge waveguide 13 is an optical waveguide that weakly limits the light field. . In addition, Figures 3 to 6 schematically show a top view, a side view, a schematic diagram of the internal structure of the grating layer and a multi-wavelength spectrum diagram of a multi-wavelength semiconductor laser provided by embodiments of the present disclosure, wherein Figures 1, 3, and The arrow in 4 indicates the direction of laser light emission.

Optionally, the ridge waveguide 13 has a width of 1.5 microns to 3 microns and a height of 1.5 microns to 2.5 microns.

Optionally, the width of the first channel 12 and the second channel 14 is 6 microns to 15 microns. The ridge waveguide 13 formed between the first channel 12 and the second channel 14 can limit the light field and obtain a single transmission mode output with a single intensity distribution.

In the embodiment of the present disclosure, the backlight surface of the ridge waveguide 13 is coated with a high-reflective film, and the light-emitting surface is coated with an anti-reflection film.

Optionally, the refractive index of the high-reflection coating and anti-reflection coating is 1 to 3. Materials for preparing high-reflective coatings and anti-reflective coatings can include SiO2, Al2O3, and MgF2, with a thickness of 0.5 microns to 3 microns.

In the embodiment of the present disclosure, the material of the substrate layer 2 includes InP; the material of the buffer layer 3 includes silicon-doped InP; the material of the lower waveguide layer 4 includes silicon-doped InP, and the doping ratio is different from that of the buffer layer 3. InP material with high Si doping is used, and the lower waveguide layer 4 uses InP material with lower Si doping; the material of the multi-quantum well active layer 5 includes InAlGaAs or InGaAsP; the material of the upper waveguide layer 6 includes Zinc doped InP; the material of the etching stop layer 8 includes Zn doped InGaAsP; the material of the cladding layer 9 includes Zn doped InP, the material of the ohmic contact layer 10 includes Zn doped InGaAs; the material of the P surface electrode layer 11 includes Titanium and platinum; the materials used for the N-side electrode layer 1 include gold, germanium and nickel.

In the embodiment of the present disclosure, the multi-quantum well active layer 5 has multiple quantum well layers and barrier layers, and the lasing wavelength is 1310 or 1550 nanometers or other communication bands. The laser uses a quantum well structure to increase the differential gain. Compared with ordinary double heterostructure lasers, quantum well lasers have the advantages of low threshold, high output power, and high modulation rate. Tensile strain or compressive strain is introduced into the quantum well structure to increase the differential gain, and the layer thickness of the well and barrier is optimized to reduce the transport time of carriers through the optical confinement layer and the escape of carriers from the active region.

In the embodiment of the present disclosure, the ridge waveguide 13 is obtained by photolithography of photoresist. After the ridge waveguide 13 is etched, referring to Figures 3 and 4, the P-surface electrode layer 11 is plated on the surface of the ohmic contact layer 10 using magnetron sputtering.

The present disclosure also provides a laser generation method, which generates laser based on the above-mentioned multi-wavelength semiconductor laser. When the laser is operating, current is pumped to the P-surface electrode layer 11 of the laser, so that the operating current of the ridge waveguide 13 and the corresponding multi-quantum well active layer 5 is above its threshold current, which is manifested as energy gain. Laser lasing is generated; at the same time, the series-connected multi-segment distributed feedback gratings with different grating constants and duty ratios in the multi-wavelength grating layer 7 act on the multi-quantum well active layer 5 at the same time, so that the longitudinal direction of the lasing is The mode pattern is consistent with the multi-wavelength longitudinal mode pattern designed in the multi-wavelength grating layer 7 to generate multi-wavelength laser lasing. This structure has the advantages of compact structure and low power consumption. It only needs one laser gain medium to achieve controllable multi-wavelength output. Then, the miniaturization and integration of multi-wavelength light sources in the optical fiber sensing system can be achieved, increasing the number of sensing array sources of the sensor while reducing the size and power consumption.

So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It should be noted that implementation methods not shown or described in the drawings or the text of the specification are all forms known to those of ordinary skill in the technical field and have not been described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, which can be simply modified or replaced by those of ordinary skill in the art.

Based on the above description, those skilled in the art should have a clear understanding of the multi-wavelength semiconductor laser and laser generation method of the present disclosure.

To sum up, the present disclosure provides a multi-wavelength semiconductor laser and a laser generation method. By introducing a variety of distributed Bragg feedback gratings with different grating periods and duty cycles in series, and working together with the multi-quantum well active layer, Realize multi-longitudinal mode mode selection and achieve stable and controllable multi-wavelength laser emission. This structure has the advantages of compact structure and low power consumption. It only needs one laser gain medium to achieve controllable multi-wavelength output. Then, the miniaturization and integration of multi-wavelength light sources in the optical fiber sensing system can be achieved, increasing the number of sensing array sources of the sensor while reducing the size and power consumption.

It should also be noted that the above are different embodiments provided by the present disclosure. These embodiments are used to illustrate the technical content of the present disclosure, but are not used to limit the scope of rights protection of the present disclosure. A feature of one embodiment can be applied to other embodiments through appropriate modification, substitution, combination, and isolation.

It should be noted that in this article, unless otherwise specified, having "a" element is not limited to having a single element, but can include one or more elements.

In addition, in this article, unless otherwise specified, ordinal numbers such as "first" and "second" are only used to distinguish multiple components with the same name, and do not indicate the existence of ranks, levels, or executions between them. Sequence, or process sequence. A "first" element and a "second" element may be present together in the same component, or they may be present in different components. The presence of one element with a higher ordinal number does not necessarily imply the presence of another element with a lower ordinal number.

In this article, unless otherwise specified, the so-called feature A "or" (or) or "and/or" (and/or) feature B means that nail exists alone, B exists alone, or A and B exist simultaneously. ; The so-called feature A "and" (and) or "and" (and) or "and" (and) feature B means that A and B exist at the same time; the so-called "include", "include", "have", " "Contains" means including but not limited to.

In addition, in this article, the so-called "upper", "lower", "left", "right", "front", "back" or "between" are only used to describe the space between multiple elements. Relative position, and can be generalized in interpretation to include translation, rotation, or mirroring. Furthermore, as used herein, "an element is on another element" or similar language does not necessarily mean that the element contacts the other element unless expressly stated otherwise.

In addition, unless the steps are specifically described or must occur in sequence, the order of the above steps is not limited to those listed above and may be changed or rearranged according to the required design. Moreover, the above-mentioned embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, the technical features in different embodiments can be freely combined to form more embodiments.

The above-mentioned specific embodiments further describe the purpose, technical solutions and beneficial effects of the present disclosure in detail. It should be understood that the above-mentioned are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this disclosure shall be included in the protection scope of this disclosure.

Claims (10)

1. A multi-wavelength semiconductor laser comprises, in order from bottom to top:

the multi-quantum well active layer comprises an N-side electrode layer (1), a substrate layer (2), a buffer layer (3), a lower waveguide layer (4), a multi-quantum well active layer (5), an upper waveguide layer (6), a multi-wavelength grating layer (7), an etching self-stop layer (8), a cladding layer (9), an ohmic contact layer (10) and a P-side electrode layer (11);

a first channel (12) and a second channel (14) which are parallel are etched in the direction from the surface of the ohmic contact layer (10) to the substrate layer (2), a ridge waveguide (13) is formed between the first channel (12) and the second channel (14), and the first channel (12) and the second channel (14) have the same size.

2. The laser according to claim 1, the first channel (12) and the second channel (14) having the same etch depth, the bottoms of the first channel (12) and the second channel (14) being above the etch self-stop layer (8).

3. The laser of claim 1, the first channel (12) and the third channel (14) having a width of 6 microns to 15 microns.

4. The laser according to claim 1, the ridge waveguide (13) having a width of 1.5 to 3 microns and a height of 1.5 to 2.5 microns.

5. The laser according to claim 1, wherein the backlight surfaces of the ridge waveguides (13) are coated with a high reflection film, and the light-emitting surfaces are coated with an antireflection film.

6. The laser of claim 5, wherein the refractive index of the highly reflective film and the anti-reflection film is 1 to 3.

7. The laser according to claim 1, wherein the multi-wavelength grating layer (7) is etched on the upper waveguide layer (6) for mode selection of laser light generated by the laser.

8. The laser according to claim 7, wherein a plurality of sections of distributed feedback gratings with different grating constants and duty ratios are arranged in series in the multi-wavelength grating layer (7), and the plurality of sections of distributed feedback gratings are used for generating multi-longitudinal mode laser excitation to the laser.

9. The laser according to claim 1, the material of the substrate layer (2) comprising InP; the material of the buffer layer (3) comprises silicon doped InP; the material of the lower waveguide layer (4) comprises silicon doped InP, and the doping proportion is different from that of the buffer layer (3); the material of the multi-quantum well active layer (5) comprises InAlGaAs or InGaAsP; the material of the upper waveguide layer (6) comprises zinc doped InP; the material of the etching self-stopping layer (8) comprises Zn doped InGaAsP; the material of the cladding layer (9) comprises Zn-doped InP, and the material of the ohmic contact layer (10) comprises Zn-doped InGaAs; the material of the P-surface electrode layer (11) comprises titanium platinum; the N-face electrode layer (1) is made of a material including gold germanium nickel.

10. A laser light generating method for generating laser light based on the multi-wavelength semiconductor laser according to any one of claims 1 to 9, the laser light generating method comprising:

current pumping is carried out on a P-face electrode layer (11) of the laser, so that the working current of a ridge waveguide (13) and a multi-quantum well active layer (5) corresponding to the ridge waveguide is above a threshold current, and the ridge waveguide and the multi-quantum well active layer represent energy gain to generate laser excitation;

the multi-section distributed feedback grating with different grating constants and duty ratios, which is arranged in the multi-wavelength grating layer (7) in series, acts on the multi-quantum well active layer (5) at the same time, so that the longitudinal mode of the laser is identical to the multi-wavelength longitudinal mode of the multi-wavelength grating layer (7) to generate multi-wavelength laser.