Semiconductor Laser Component and Method for Operating at Least One Semiconductor Laser

Abstract

In an embodiment a semiconductor laser component includes a plurality of semiconductor lasers, each of the semiconductor lasers configured to emit primary electromagnetic radiation of a primary spectral bandwidth in a visible wavelength range and a beam combiner configured to combine the primary electromagnetic radiations emitted from the semiconductor lasers, form secondary electromagnetic radiation from a superposition of the primary electromagnetic radiations of the semiconductor lasers and couple the secondary electromagnetic radiation out from the beam combiner, wherein the secondary electromagnetic radiation has a secondary spectral bandwidth that is at least twice as large as an average value of the primary spectral bandwidths.

Claims

1.-20. (canceled)

21. A method for operating at least one semiconductor laser, the method comprising: operating each semiconductor laser in pulsed mode so that operation predominantly takes place in an increase region of the semiconductor laser, wherein each semiconductor laser has a characteristic curve of its optical output power over its operating time which initially has the increase region and subsequently a stationary region.

22. The method according to claim 21, wherein at least two semiconductor lasers are operated simultaneously pulsed in their increase region, or wherein at least two semiconductor lasers are operated successively pulsed in their increase region.

23. A semiconductor laser component comprising: a plurality of semiconductor lasers, each of the semiconductor lasers configured to emit primary electromagnetic radiation of a primary spectral bandwidth in a visible wavelength range; and a beam combiner configured to: combine the primary electromagnetic radiations emitted from the semiconductor lasers, form secondary electromagnetic radiation from a superposition of the primary electromagnetic radiations of the semiconductor lasers, and couple the secondary electromagnetic radiation out from the beam combiner, wherein the secondary electromagnetic radiation has a secondary spectral bandwidth that is at least twice as large as an average value of the primary spectral bandwidths.

24. The semiconductor laser component according to claim 23, wherein the secondary spectral bandwidth is between 5 nm and 10 nm, inclusive.

25. The semiconductor laser component according to claim 23, wherein the beam combiner is a monolithic component.

26. The semiconductor laser component according to claim 23, wherein the semiconductor lasers have different resonator lengths.

27. The semiconductor laser component according to claim 23, wherein the semiconductor lasers are arranged on a common substrate.

28. The semiconductor laser component according to claim 27, further comprising a thermal insulating layer arranged between at least one semiconductor laser and the substrate.

29. The semiconductor laser component according to claim 28, wherein the insulating layer comprises silicon oxide or silicon nitride.

30. The semiconductor laser component according to claim 23, wherein at least some of the semiconductor lasers are arranged on a separate substrate.

31. The semiconductor laser component according to claim 23, wherein at least one semiconductor laser comprises a doping with a dopant that changes a main emission wavelength of the semiconductor laser.

32. The semiconductor laser component according to claim 23, wherein the semiconductor lasers are formed in a monolithic semiconductor body.

33. The semiconductor laser component according to claim 23, wherein the semiconductor lasers are arranged at different lateral distances from one another.

34. The semiconductor laser component according to claim 23, further comprising an actuator configured to generate a time-modulated mechanical stress in at least one semiconductor laser.

35. The semiconductor laser component according to claim 34, wherein the actuator comprises a piezo element.

36. The semiconductor laser component according to claim 23, further comprising an actuator associated with the semiconductor lasers, each actuator generating a time-modulated mechanical stress on the semiconductor lasers.

37. The semiconductor laser component according to claim 23, wherein a gradient mirror is arranged at an output coupling region of at least one semiconductor laser.

38. The semiconductor laser component according to claim 23, further comprising a dielectric mirror arranged at an output coupling region of at least one semiconductor laser.

39. The semiconductor laser component according claim 23, wherein the semiconductor lasers are mounted on the beam combiner.

40. A semiconductor laser component comprising: a plurality of semiconductor lasers, wherein each of the semiconductor lasers is configured to emit primary electromagnetic radiation of a primary spectral bandwidth in a visible wavelength range; a beam combiner configured to: combine radiation emitted from the semiconductor lasers, form a superposition of the primary electromagnetic radiations of the semiconductor lasers, couple secondary electromagnetic radiation out of the beam combiner, wherein the secondary electromagnetic radiation has a secondary spectral bandwidth that is at least twice as large as an average value of the primary spectral bandwidths; and an optical layer sequence arranged within a resonator of at least one semiconductor laser, wherein a refractive index of which is variable by applying of an external electric voltage or electric current.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Further advantages and advantageous embodiments and further embodiments of the semiconductor laser component result from the following embodiments illustrated in connection with the figures.

[0042] FIG. 1 shows a schematic top view of a semiconductor laser component described herein according to a first embodiment;

[0043] FIG. 2 shows a schematic top view of a semiconductor laser component described herein according to a second embodiment;

[0044] FIG. 3 shows a schematic top view of a semiconductor laser component described herein according to a third embodiment

[0045] FIG. 4 shows a schematic top view of a semiconductor laser component described herein according to a fourth embodiment;

[0046] FIG. 5 shows a schematic top view of a semiconductor laser component described herein according to a fifth embodiment;

[0047] FIG. 6 shows a diagram of a characteristic curve of the intensity of the emitted electromagnetic radiation of a semiconductor laser over time according to a first embodiment of a method for operating semiconductor lasers described herein;

[0048] FIG. 7 shows diagrams of characteristic curves of the intensity of the emitted electromagnetic radiation of several semiconductor lasers over time according to a second embodiment of a method for operating semiconductor lasers described herein;

[0049] FIG. 8 shows diagrams of characteristic curves of the intensity of the emitted electromagnetic radiation of several semiconductor lasers over time according to a third embodiment of a method for operating semiconductor lasers described herein; and

[0050] FIG. 9 shows a schematic sectional view of a semiconductor laser component described herein according to a sixth embodiment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0051] Elements that are identical, similar or have the same effect are given the same reference signs in the figures. The figures and the proportions of the elements shown in the figures are not to be regarded as to scale. Rather, individual elements may be shown exaggeratedly large for better representability and/or for better comprehensibility.

[0052] FIG. 1 shows a schematic top view of a semiconductor laser component 1 described herein according to a first embodiment. The semiconductor laser component 1 includes a beam combiner 20 and a plurality of semiconductor lasers 10 on a common substrate 30. The beam combiner 20 includes a plurality of waveguides 21 embedded in the beam combiner 20. Further, the beam combiner 20 includes a plurality of input coupling surfaces 20A and an output coupling surface 20B.

[0053] The beam combiner 20 is formed with a translucent or transparent material. Preferably, the waveguides 21 are inscribed into the material of the beam combiner 20 by means of a laser. Such waveguides 21 are characterized by a particularly high optical efficiency. The waveguides 21 are arranged in such a way that all electromagnetic radiation coupled in via the input coupling surfaces 20A are combined with each other and coupled out in the common output coupling surface 20B.

[0054] The semiconductor lasers 10 are arranged on a common substrate 30 and each comprise a resonator 100. The resonators 100 each extend along the semiconductor lasers 10 to an output coupling region 60. A gradient mirror or a dielectric mirror, for example, is arranged at the output coupling region 60. In particular, an optical layer sequence 70 is arranged in the resonator 100 at the output coupling region 60, the refractive index of which can be changed, for example, by applying an external electrical voltage or an electrical current. Thus, by means of a time-variable refractive index, a change in the optical and/or actual length of the resonator 100 can be produced. By means of a time-varying electrical voltage, the refractive index of the optical layer sequence 70 can be modulated. A temporally modulated resonator length 100A causes, among other things, an increased primary spectral bandwidth of the semiconductor laser 10.

[0055] Each semiconductor laser 10 emits a respective primary electromagnetic radiation of a primary spectral bandwidth in the direction parallel to its resonator axis 100, and couples this primary electromagnetic radiation into the beam combiner 20. In the beam combiner 20, these primary electromagnetic radiations are guided and superimposed with each other in the waveguides 21 and finally coupled out as a secondary electromagnetic radiation at an output coupling surface 20B of the beam combiner 20. The coupled-out secondary electromagnetic radiation from the beam combiner 20 has a secondary spectral bandwidth that is at least twice the arithmetic mean of the respective primary spectral bandwidths of the electromagnetic radiations of the semiconductor lasers 10.

[0056] An actuator 50 is arranged on the opposite side of an output coupling region 60 of a semiconductor laser 10. The actuator 50 comprises a piezoelectric element and is used for modulated mechanical stressing of the semiconductor laser 10, thereby increasing the primary spectral bandwidth of the primary electromagnetic radiation emitted from that semiconductor laser 10.

[0057] FIG. 2 shows a schematic top view of a semiconductor laser component 1 described herein according to a second embodiment of a semiconductor laser component 1. The second embodiment is substantially the same as the first embodiment shown in FIG. 1. However, the semiconductor lasers 10 differ in the length of their resonators 100, each semiconductor laser 10 having a different resonator length 100A.

[0058] The different resonator lengths 100A result in different main emission wavelengths of the respective semiconductor lasers 10, allowing a further increase in the secondary spectral bandwidth of the secondary electromagnetic radiation.

[0059] FIG. 3 shows a schematic top view of a semiconductor laser component 1 described herein according to a third embodiment example. The third embodiment example shown in FIG. 3 is substantially the same as the first embodiment example of a semiconductor laser component 1 shown in FIG. 1.

[0060] In contrast to the first embodiment, each semiconductor laser 10 is arranged on a separate substrate 30. The arrangement on separate substrates 30 enables a particularly simple influencing of a thermal resistance and/or an electrical resistance between a semiconductor laser 10 and the associated substrate 30.

[0061] For example, each substrate 30 has a different material. Thus, a different operating temperature and/or electrical behavior of each semiconductor laser 10 can be achieved. This advantageously results in an increased secondary spectral bandwidth of the secondary electromagnetic radiation. Some of the semiconductor lasers 10 are disposed on a substrate 30 formed with a material having a reduced thermal conductivity. These semiconductor lasers 10 have difficulty dissipating their waste heat generated during operation and thus reach an elevated operating temperature, resulting in an altered main emission wavelength.

[0062] FIG. 4 shows a schematic top view of a semiconductor laser component 1 described herein according to a fourth embodiment. The fourth embodiment shows a monolithic semiconductor body 11 in which a plurality of semiconductor lasers 10 are formed. Each semiconductor laser 10 includes a resonator 100, and the resonators 100 are aligned parallel to each other. The monolithic semiconductor body 11 is disposed on a substrate 30. By means of a monolithic semiconductor body 11, a particularly compact design of the semiconductor laser component can be realized. For example, different semiconductor lasers 10 comprise a different doping to cause different main emission wavelengths, respectively.

[0063] FIG. 5 shows a schematic top view of a semiconductor laser component 1 described herein according to a fifth embodiment. The fifth embodiment is substantially the same as the fourth embodiment shown in FIG. 4.

[0064] In contrast to the fourth embodiment, the resonators 100 formed in the monolithic semiconductor body 11 have different lengths 100A. The different lengths 100A of the resonators 100 are realized by means of mesa edges etched at different locations. Thus, a plurality of different resonator lengths 100A can be realized within the laser bar 11. By means of the different resonator lengths 100A, a different main emission wavelength of the different semiconductor lasers 10 can be generated particularly easily and, at the same time, a compact design is maintained due to the arrangement in a monolithic semiconductor body 11.

[0065] FIG. 6 shows a diagram of a characteristic curve of the intensity of the emitted electromagnetic radiation of a semiconductor laser 10 over time according to a first embodiment of a method for operating semiconductor lasers 10 described herein. The Y-axis represents the intensity of the emitted primary electromagnetic radiation of a semiconductor laser 10. The X-axis represents the time axis. The intensity starts to increase only after the laser threshold is exceeded and increases steadily up to a certain limit value. The limit value marks the transition from an increase region A and a subsequent stationary region B. After leaving the increase region A, the semiconductor laser 10 is in the stationary region B.

[0066] During emission of electromagnetic radiation in the increase region A, an increased primary spectral bandwidth with a decreased coherence length is observed. Operation of the semiconductor laser 10 in the stationary region B corresponds to a stable operating point and occurs with a substantially reduced primary spectral bandwidth and thus with an increased coherence length. Thus, operation of the laser within the increase region A advantageously has a low coherence length and a high primary spectral bandwidth. For example, the semiconductor laser 10 may be pulsed to achieve operation exclusively within the increase region A. The brightness of the semiconductor lasers 10 is given by the integral of the intensity over time. If the semiconductor lasers 10 are switched off again shortly after being switched on in order to achieve the widest possible spectral bandwidth, the value of the integrated brightness will be low. Consequently, for example, a pixel generated by the semiconductor laser 10 also appears relatively dark.

[0067] FIG. 7 shows diagrams of characteristic curves of the intensity of the emitted electromagnetic radiation of several semiconductor lasers 10 over time according to a second embodiment of a method described here for operating of semiconductor lasers 10. To achieve a quasi-continuous continuous operation of the semiconductor lasers 10, several semiconductor lasers 10 can be operated one after the other, each of them operating only within the increase region A. A first semiconductor laser 10 is operated up to the increase region A and then switched off, while directly following this is the operation of a further semiconductor laser 10 which is also operated only in the increase region A and then switched off. By continuing this series further, quasi-continuous operation of a plurality of semiconductor lasers 10 can be achieved.

[0068] FIG. 8 shows diagrams of characteristic curves of the intensity of the emitted electromagnetic radiation of several semiconductor lasers 10 over time according to a third embodiment of a method for operating semiconductor lasers 10 described here. To increase the emitted intensity, simultaneous operation of a plurality of semiconductor lasers 10 is conceivable. For example, a plurality of semiconductor lasers 10 are operated only in their increase region A and thus in an operating mode with a high primary spectral bandwidth. The simultaneous superposition of the primary electromagnetic radiation increases the optical intensity of the generated primary electromagnetic radiation.

[0069] Alternatively, a combination of the operation modes according to the embodiment example shown in FIG. 7 and the embodiment example shown in FIG. 8 is also possible. For example, sequential operation of a plurality of semiconductor lasers 10 can be alternately performed to generate emission as continuously as possible, and simultaneous emission of a plurality of semiconductor lasers 10 can be alternately performed to generate emission as intensely as possible.

[0070] FIG. 9 shows a schematic sectional view of a semiconductor laser component 1 described herein according to a sixth embodiment. The semiconductor laser component 1 shown here comprises a common substrate 30 on which three semiconductor lasers 10 are arranged. An insulating layer 40 is disposed between each of the semiconductor lasers 10 and the substrate 30.

[0071] The insulating layer 40 has different thicknesses and thus can cause different thermal and/or electrical resistances between the semiconductor lasers 10 and the substrate 30. Additionally or alternatively, the insulating layer 40 may be locally patterned to further affect a thermal and/or electrical resistance. By means of the differently designed insulating layer 40, an operating temperature of each semiconductor laser 10 can thus be specifically influenced. By varying the operating temperatures as much as possible, a further reduction of the coherence length and thus an increase of the primary spectral bandwidth can be achieved.

[0072] The invention is not limited by the description based on the embodiments. Rather, the invention encompasses any new feature as well as any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or combination itself is not explicitly stated in the patent claims or embodiments.