Laser device
By employing a combined structure of gain section, reflector section and distributor in the laser device, the optical path is changed and stray light is suppressed, thus solving the problem of decreased detection accuracy when the output optical power of the laser device is increased, and achieving higher detection reliability and accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- FURUKAWA ELECTRIC CO LTD
- Filing Date
- 2021-02-10
- Publication Date
- 2026-05-12
AI Technical Summary
When existing laser devices increase the output light power, the power of the output light at the rear decreases, making it difficult to detect characteristics such as wavelength.
The system employs a combined structure of a gain section, a first reflection section, a second reflection section, a distributor, and a waveguide. By splitting the laser into a first beam and a second beam and outputting them in different directions, and by using a bending section to change the optical path, the system suppresses the influence of stray light and improves detection accuracy.
This makes it easier to detect characteristics such as laser wavelength, thus improving the reliability and accuracy of detection.
Smart Images
Figure CN115066815B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to laser devices. Background Technology
[0002] Conventionally, laser devices are known to include a first reflector, a second reflector, and a gain section between the first reflector and the second reflector, and to emit laser light from an emission end (front end) opposite to the second reflector and the gain section relative to the first reflector (e.g., Patent Document 1).
[0003] In this laser device, the following operation is performed: the rear output light output from the end (rear end) opposite to the transmission output end of the second reflector is monitored using a measuring device such as a wavelength meter or a power meter (Patent Document 1).
[0004] Prior art literature
[0005] Patent documents
[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-140308 Summary of the Invention
[0007] -The problem to be solved by the invention-
[0008] However, in the aforementioned existing laser devices, if the reflectivity of the second reflector is increased in order to improve the power of the output light of the laser device, there are problems such as reduced power of the output light and difficulty in detecting wavelengths.
[0009] Therefore, one of the objectives of this invention is to obtain a laser device that makes it easier to detect characteristics such as the wavelength of a laser.
[0010] -Methods used to solve problems-
[0011] The laser device of the present invention includes, for example: a gain section; a first reflective section; a second reflective section disposed on the opposite side of the first reflective section relative to the gain section; a distributor disposed on the opposite side of the gain section relative to the first reflective section, and distributing the laser light from the first reflective section into a first light and a second light; a first end portion disposed separately from the distributor in a first direction, and located on the opposite side of the first reflective section relative to the distributor, and outputting the first light or an amplified version of the first light as an outgoing light; and a second end portion disposed separately from the distributor in a second direction different from the first direction relative to the distributor, and outputting the second light.
[0012] Furthermore, the laser device includes, for example, a waveguide having a bend and connecting the distributor to the second end.
[0013] Furthermore, in the laser device, for example in the curved section, the direction of travel of the second light changes by approximately 180°.
[0014] Furthermore, in the laser device, for example, the first end and the second end are located at one end and the other end of the laser device along its length, respectively.
[0015] Furthermore, in the laser device, for example, the second reflector is a ring resonator filter.
[0016] Furthermore, in the laser device, for example, the second reflector is a mirror.
[0017] In addition, in the laser device, for example, the reflector is of the DBR type.
[0018] Furthermore, the laser device may include an optical amplifier, for example, between the first reflective portion and the first end portion.
[0019] Furthermore, in the laser device, for example, the optical amplifier is located between the distributor and the first end.
[0020] Furthermore, in the laser device, for example, the optical amplifier is located between the first reflector and the distributor.
[0021] -Invention Effects-
[0022] According to the present invention, a laser device can be obtained that makes it easier to detect characteristics such as the wavelength of a laser. Attached Figure Description
[0023] Figure 1 This is an exemplary and schematic top view of the laser device according to the embodiment.
[0024] Figure 2 This is an exemplary and schematic top view of the laser device of the first modified example.
[0025] Figure 3 This is an exemplary and schematic top view of the laser device of the second variation.
[0026] Figure 4 This is an illustrative and schematic top view of the laser device in the third variation. Detailed Implementation
[0027] Hereinafter, exemplary embodiments and modifications of the present invention are disclosed. The structures of the embodiments and modifications shown below, as well as the effects and results (compliance) resulting from such structures, are merely examples. The present invention can also be achieved through structures other than those disclosed in the embodiments and modifications below. Furthermore, according to the present invention, at least one of various effects (including derivative effects) obtained through the structure can be obtained.
[0028] The embodiments and variations shown below have the same structure. Therefore, based on the structure of each embodiment and variation, the same function and effect based on this same structure can be obtained. Furthermore, the same reference numerals are used for those same structures below, and repeated descriptions are sometimes omitted.
[0029] In this specification, the ordinal numbers are assigned for the convenience of distinguishing parts, locations, etc., and do not indicate priority or order.
[0030] Furthermore, in each diagram, the X-direction is represented by an arrow X, and the Y-direction by an arrow Y. The X and Y directions intersect and are orthogonal to each other. Additionally, the X-direction can also be referred to as the length direction or longitudinal direction, and the Y-direction can also be referred to as the short side direction, width direction, or transverse direction.
[0031] [Implementation Method]
[0032] [Structure of the laser device]
[0033] First, the structure of the laser device 10A according to the embodiment will be described. Figure 1 This is a top view of laser device 10A. (Example) Figure 1 As shown, the laser device 10A includes a first DBR section 11, a ring resonator filter 12A, a gain section 13, an optical amplifier 14, and a distributor 15. The laser device 10A is a semiconductor laser element and a wavelength-variable laser element. The laser device 10A is disposed on a semiconductor multilayer substrate 20. The semiconductor multilayer substrate 20 is configured to have multiple semiconductor layers stacked on a semiconductor substrate and to have given functions such as waveguides.
[0034] The first DBR section 11, the ring resonator filter 12A, the gain section 13, the optical amplifier 14, and the distributor 15 are all made of InP-based semiconductor materials.
[0035] The first DBR section 11 has a waveguide (not shown) with a structure including a distributed Bragg-type sampling grating (SG-DBR). The first DBR section 11 is an example of a first reflector and also an example of a reflector.
[0036] The ring resonator filter 12A includes: a ring waveguide 12a with a ring shape; and two optically coupled waveguides 12b1 and 12b2 that input and output laser light to the ring waveguide 12a. The optically coupled waveguides 12b1 and 12b2 are optically coupled to the ring waveguide 12a on opposite sides sandwiching it. The optically coupled waveguides 12b1 and 12b2 have segmental arms that branch off from a waveguide 12c connected to the gain section 13 at a position separating them from the ring waveguide 12a toward the first DBR section 11, and connection portions for input and output light to the ring waveguide 12a. The connection portions are, for example, multimode interference waveguide type directional couplers. Multimode interference waveguide type directional couplers can be used as the optically coupled waveguides 12b1 and 12b2, for example. The ring resonator filter 12A, having the structure described above, functions as a reflector whose reflection characteristics periodically change with respect to the wavelength of light input from waveguide 12c. The ring resonator filter 12A is an example of a second reflector.
[0037] The gain section 13 has a waveguide (not shown) fabricated through an active layer.
[0038] In addition, the optical amplifier 14 has a waveguide (not shown) fabricated through an active layer.
[0039] In the above structure, the active layer has a multiple quantum well (MQW) structure, for example, comprising GaInAsP-based or AlGaInAs-based semiconductor materials. The passive waveguide is fabricated, for example, using an i-type GaInAsP-based semiconductor material with a bandgap wavelength of 1300 nm. The waveguide of the SG-DBR structure, fabricated, for example, using GaInAsP-based or AlGaInAs-based semiconductor materials, has portions with different refractive indices periodically arranged to form a diffraction grating.
[0040] Miniature heaters (not shown) are provided in the first DBR section 11 and the ring resonator filter 12A, respectively. These miniature heaters are so-called resistive heating elements that generate heat according to the supply of current. Each miniature heater has a wiring structure such as electrodes and conductor layers for supplying current.
[0041] The first DBR section 11 and the ring resonator filter 12A constitute a laser resonator. The first DBR section 11 has comb-shaped reflection peaks with periodic frequency intervals, determined by the reciprocal of the period of the diffraction grating. The different periods of the first DBR section 11 and the ring resonator filter 12A create a structure that allows for coarse tuning of the laser frequency using a method known as a vernier type. A microheater heats the first DBR section 11, causing a change in its refractive index, thereby shifting the comb-shaped reflection peaks towards the frequency axis. Similarly, the microheater heats the ring resonator filter 12A, causing a change in its refractive index, also shifting the comb-shaped reflection peaks towards the frequency axis.
[0042] The gain section 13 is located between the first DBR section 11 and the ring resonator filter 12A. In other words, the ring resonator filter 12A is positioned on the opposite side of the first DBR section 11 relative to the gain section 13. A pair of mutually isolated electrodes (not shown) are provided in the gain section 13. By applying a voltage to the pair of electrodes, current flows through the gain section 13, resulting in optical amplification. This generates laser oscillation.
[0043] The distributor 15 is located on the opposite side of the gain section 13 and the ring resonator filter 12A relative to the first DBR section 11. The distributor 15 splits the laser propagating from the first DBR section 11 in the waveguide 20a into a first beam toward the optical amplifier 14 and a second beam different from the first beam. The first beam is directed toward the optical amplifier 14 via the waveguide 20b1, and the second beam is directed toward the end 10b via the waveguide 20b2.
[0044] Optical amplifier 14 is located opposite to gain section 13 and ring resonator filter 12A relative to first DBR section 11, and is situated between first DBR section 11 and end 10a, which serves as the laser emission end. First light is input to optical amplifier 14 from distributor 15 via waveguide 20b1. By applying voltage to optical amplifier 14 via electrodes (not shown), current flows through optical amplifier 14, resulting in optical amplification. Optical amplifier 14 optically amplifies the laser light output from first DBR section 11 via laser oscillation, which in this embodiment is the first light from distributor 15.
[0045] The laser device 10A outputs laser light amplified by the optical amplifier 14 from end 10a, i.e., the first light amplified by the optical amplifier 14. The laser light emitted from end 10a is the emitted light of the laser device 10A. End 10a is an example of the first end and can also be referred to as the emitting end or the front end.
[0046] The waveguide 20b2 of the second light distributed by the distributor 15 has a bend 20b21. The bend 20b21 has a U-shaped form. Therefore, the travel direction of the second light changes by 180° in the bend 20b21.
[0047] The output ratio of the first light in the distributor 15 relative to the input light is preferably 80% or more and 99% or less, and more preferably 95% or more.
[0048] The second light is output from end 10b of waveguide 20b2, which is opposite to the distributor 15. End 10b is an example of a second end.
[0049] like Figure 1 As shown, end 10a is disposed separately from dispenser 15 in the X direction. Furthermore, end 10b is disposed separately from dispenser 15 in a D1 direction, which is different from the X direction. Additionally, end 10a is located at the end of the laser device 10A (semiconductor multilayer substrate 20) in the X direction, and end 10b is located at the end of the laser device 10A (semiconductor multilayer substrate 20) in the opposite direction of the X direction. The X direction is an example of a first direction, and the D1 direction is an example of a second direction.
[0050] As explained above, in this embodiment, the distributor 15 distributes the laser light from the first DBR section 11 (first reflector section) into a first light and a second light. The end 10a (first end) outputs the first light, amplified by the optical amplifier 14, as the output light of the laser device 10A. The end 10b (second end) outputs the second light.
[0051] That is, according to the above structure, the second light distributed by the distributor 15 can be used in the inspection. According to the above structure, for example, compared with the case where the light transmitted without being reflected by the second reflector, i.e., the leaked light, is used in the inspection, a more reliable laser output can be used in the inspection, thereby obtaining a more reliable or more accurate inspection result.
[0052] Furthermore, in this embodiment, end 10a is disposed separately from dispenser 15 in the X direction (first direction) and is located on the opposite side of first DBR portion 11 relative to dispenser 15. Additionally, end 10b is disposed separately from dispenser 15 in a D1 direction (second direction) different from the X direction.
[0053] Light not optically coupled to waveguides 20b1 and 20b2 in the distributor 15 becomes stray light traveling in the semiconductor layer surrounding the waveguides in the semiconductor laminate substrate 20. This stray light easily enters the input direction of light from the first DBR section 11 to the distributor 15, i.e., the X direction. Therefore, assuming that the end 10b is separately arranged relative to the distributor 15 in the X direction, stray light becomes easily mixed into the output light from the end 10b, which may affect the detection accuracy. The output light from the end 10b is usually much weaker than the output light from the end 10a, and is therefore more affected by stray light. In this respect, in this embodiment, the end 10a is located on the opposite side of the first DBR section 11 relative to the distributor 15, and the direction in which the end 10a exists relative to the distributor 15 (X direction, first direction) and the direction in which the end 10b exists relative to the distributor 15 (D1 direction, second direction) are different from each other. Therefore, stray light can be suppressed from mixing into the second light (detection light) output from the end 10b, thereby further improving the inspection accuracy.
[0054] Furthermore, in this embodiment, the laser device 10A includes a waveguide 20b2 that connects the distributor 15, which has a bend 20b21, and the end 10b. In addition, in this embodiment, the travel direction of the second light changes by approximately 180° in the bend 20b21. Furthermore, in this embodiment, the end 10a and end 10b are located at one end and the other end of the laser device 10A along its length (X direction), respectively.
[0055] Based on these structures, it is possible to achieve a configuration that makes it difficult for stray light to get mixed into the end 10b.
[0056] Furthermore, in this embodiment, the ring resonator filter 12A (reflector) is an example of a second reflector.
[0057] The structure that achieves the above-mentioned effect can be applied to a laser device 10A that has a ring resonator filter 12A as a second reflector.
[0058] Furthermore, in this embodiment, the optical amplifier 14 is located between the first DBR section 11 and the end section 10a.
[0059] The structure that achieves the above-mentioned effect can be applied to a laser device 10A that has an optical amplifier 14 between the first DBR section 11 and the end section 10a.
[0060] Furthermore, in this embodiment, the optical amplifier 14 is located between the distributor 15 and the end 10a.
[0061] The structure that achieves the above-mentioned effect can be applied to a laser device 10A that has an optical amplifier 14 between the distributor 15 and the end 10a.
[0062] [First Variation]
[0063] Figure 2 This is a top view of the laser device 10B of the first modified example. The laser device 10B of this modified example has the same structure as the laser device 10A of the embodiment, except that the positions of the optical amplifier 14 and the distributor 15 are reversed. That is, in this modified example, the optical amplifier 14 is located between the first DBR section 11 and the distributor 15.
[0064] Even with the structure described above, the same effect as the above-described implementation can be obtained.
[0065] [Second variation]
[0066] Figure 3 This is a top view of the laser device 10C of the second modification. The laser device 10C of this modification has the same structure as the laser device 10A of the embodiment, except that it does not have the optical amplifier 14.
[0067] Even with the structure described above, the same effect as the above-described implementation can be obtained.
[0068] [Third variation]
[0069] Figure 4 This is a top view of the laser device 10D of the third modification. The laser device 10D of this modification has the same structure as the laser device 10A of the embodiment except for the following aspects: (1) it has a second DBR section 12B instead of the ring resonator filter 12A as a second reflector; (2) it has a phase adjustment section 16; and (3) the positions of the end 10c and the end 10b as the second end are different.
[0070] Like the first DBR section 11, the second DBR section 12B has a waveguide (not shown) including an SG-DBR structure. The second DBR section 12B is an example of a second reflector, and is an example of a reflector.
[0071] The phase adjustment unit 16 is located between the first DBR unit 11 and the second DBR unit 12B. In this embodiment, the phase adjustment unit 16 is located between the gain unit 13 and the second DBR unit 12B. Alternatively, the phase adjustment unit 16 may be located between the gain unit 13 and the first DBR unit 11.
[0072] The phase adjustment section 16 has a passive waveguide (not shown).
[0073] Additionally, a miniature heater (not shown) is also provided in the phase adjustment section 16. The miniature heater is a so-called resistive heating element that heats up according to the supply of current. The miniature heater is provided with a wiring structure such as electrodes or conductor layers for supplying current.
[0074] A miniature heater heats the phase adjustment section 16, causing a change in its refractive index, thereby adjusting the optical length of the laser resonator. By adjusting the optical length of the laser resonator, it is possible to fine-tune the frequency of the resonator mode (cavity mode) while simultaneously shifting it towards the frequency axis. This fine-tuning of the resonator mode allows for selection of the resonator mode during laser oscillation and enables frequency variations within a small range. Furthermore, the phase adjustment section 16 described above can also be applied to the above-described embodiment, the first modification, and the second modification.
[0075] End portion 10c is located at the end of the laser device 10D (semiconductor laminate substrate 20) in the Y direction (short side direction, width direction). In the bend 20b21 of the waveguide 20b2, the travel direction of the second light changes by approximately 90°. Furthermore, in this modified example, end portion 10c and distributor 15 are separately configured in the D2 direction (second direction) different from the X direction.
[0076] As explained above, in this embodiment, the second DBR section 12B (DBR type reflector, reflector) is an example of a second reflector.
[0077] Even with the structure described above, the same effects as the above-described embodiments can be achieved. Furthermore, this modification also offers the following advantages: for example, it simplifies the device structure.
[0078] In addition, Figure 4 In the structure, either the second DBR section 12B can be replaced by a ring resonator filter 12A, or... Figures 1-3 In any of the structures, a second DBR section 12B is provided instead of the ring resonator filter 12A.
[0079] The above examples illustrate embodiments and modifications of the present invention. These embodiments and modifications are merely examples and are not intended to limit the scope of the invention. The above embodiments and modifications can be implemented in a variety of other ways, and various omissions, substitutions, combinations, and changes can be made without departing from the spirit of the invention. In addition, the specifications (construction, type, orientation, form, size, length, width, thickness, height, quantity, arrangement, position, material, etc.) of various structures, shapes, etc., can be appropriately modified before implementation.
[0080] -Industry availability-
[0081] This invention can be used in laser devices.
[0082] -Symbol Explanation-
[0083] 10A~10D...Laser Device
[0084] 10a... End (First End)
[0085] 10b... End (Second End)
[0086] 10c... End (Second End)
[0087] 11...First DBR section (first reflector section)
[0088] 12A... Ring resonator filter (second reflector)
[0089] 12B...Second DBR section (second reflector, DBR type reflector, reflector)
[0090] 12a... Ring waveguide
[0091] 12b1, 12b2... Optical Coupled Waveguides
[0092] 12c...waveguide
[0093] 13... Gain section
[0094] 14... Optical Amplifier
[0095] 15...Distributor
[0096] 16...Phase Adjustment Section
[0097] 20...Semiconductor laminate substrate
[0098] 20a...waveguide
[0099] 20b1...waveguide
[0100] 20b2...waveguide
[0101] 20b21...bend
[0102] X... direction (first direction, length direction)
[0103] Y... direction (short side direction)
[0104] D1...direction (second direction)
[0105] D2... direction (second direction).
Claims
1. A laser device comprising: Gain section; First reflector; The second reflective portion is disposed on the opposite side of the first reflective portion relative to the gain portion; A distributor is disposed on the opposite side of the gain section relative to the first reflector, and distributes the laser light from the first reflector into a first beam and a second beam; The first end is disposed separately from the distributor in a first direction, and is located on the opposite side of the first reflective portion relative to the distributor, and outputs the first light or the amplified first light as the outgoing light. as well as The second end, relative to the distributor, is configured separately from the distributor in a second direction different from the first direction, and outputs the second light as a detection light. In the distributor, the output ratio of the first light relative to the laser light from the first reflector is 80% or more and 99% or less. Only a waveguide is located between the distributor and the second end, and the waveguide propagates the second light without amplification. The first end and the second end are respectively located at one end and the other end along the length of the laser device. In the distributor, light that is not optically coupled to the waveguides of the first and second lights becomes stray light. The orientations of the first end relative to the distributor and the orientations of the second end relative to the distributor are different, thereby suppressing stray light from mixing into the second light output from the second end. The waveguide of the second light has a bend. In the curved section, the direction of travel of the second light changes by approximately 180°. The output light from the second end is weaker than the output light from the first end, and the stray light travels in the direction of light input from the first reflector to the distributor.
2. The laser device according to claim 1, wherein, The second reflector is a ring resonator filter.
3. The laser device according to claim 1, wherein, The second reflective part is a reflector.
4. The laser device according to claim 3, wherein, The reflector is of the DBR type.
5. The laser device according to claim 1, wherein, An optical amplifier is provided between the first reflective portion and the first end portion.
6. The laser device according to claim 5, wherein, The optical amplifier is located between the distributor and the first end.
7. The laser device according to claim 5, wherein, The optical amplifier is located between the first reflector and the distributor.