| 1. |
- Hillmer, H., et al.
(författare)
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Wide continuously tunable 1.55 μm vertical air-cavity wavelength selective elements for filters and VCSELs using micromachined actuation
- 2005
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Ingår i: Opto-Ireland 2005. - : SPIE - International Society for Optical Engineering. - 0819458104 ; , s. 14-28
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Konferensbidrag (refereegranskat)abstract
- Tailored scaling allows the effectiveness of physical effects and mechanical stability to be enhanced. This is shown for micromachined 1.55μm vertical-resonator-based filters and VCSELs, capable of wide, continuous, and kink-free tuning by a single control parameter. Tuning is achieved by mechanically actuating one or several membranes in a vertical air-gap resonator including two highly reflective DBR mirrors. Electrostatically actuatable single-chip filters including InP/air-gap DBR's (3.5 periods) reveal a continuous tuning up to 14% of the absolute wavelength. Varying a reverse voltage (U=0 .. -3.2V) between the membranes (almost flat in the unactuated condition) a tuning range up to 142nm was obtained. Varying a reverse voltage (U=0 .. -28V) between the membranes (strained and curved in the unactuated condition) a tuning range up to 221nm was obtained. Optically pumped and continuously tunable 1.55μm VCSELs show 26nm spectral tuning range, 400μW maximum output power, and 57dBm SMSR. This two-chip VCSEL has a movable top mirror membrane, which is precisely designed to obtain a specific air-gap length and a tailored radius of curvature in order to efficiently support the fundamental optical mode of the plane-concave resonator. The curved top mirror DBR membrane consists of periodically alternating differently stressed silicon nitride and silicon dioxide multilayers. The lower InP-based part consists of the InP/GaInAsP bottom DBR and the GaInAsP active region.
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| 2. |
- Lindberg, H, et al.
(författare)
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0.8W optically pumped vertical external cavity surface emitting laser operating CW at 1550 nm
- 2004
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 40:10, s. 601-602
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Tidskriftsartikel (refereegranskat)abstract
- An InP based optically pumped vertical external cavity surface emitting laser has been designed and optimised for emission at 1550 nm. To overcome thermal limitations an intra-cavity synthetic diamond heatspreader is bonded to the gain structure. The laser produces 780 mW at -30degreesC and 100 mW at 20degreesC in a near Gaussian beam (M-2 < 1.2).
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| 3. |
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| 4. |
- Lindberg, Hans, 1977, et al.
(författare)
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High-power optically pumped 1550-nm VECSEL with a bonded silicon heat spreader
- 2004
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 16:5, s. 1233-1235
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Tidskriftsartikel (refereegranskat)abstract
- We present an optically pumped 1550-nm vertical-external-cavity surface-emitting laser with improved output power and operating temperature using a bonded heat spreader. The laser comprises an InGaAsP-based gain element, with a resonant periodic gain structure on top of a distributed Bragg reflector, and a high reflectivity spherical mirror as the external reflector. Heat transport is enhanced by a Si heat spreader bonded to the InGaAsP surface by liquid capillary bonding. Optical pumping is achieved using a 1250-nm fiber Raman laser. A maximum continuous output power of 250 mW was obtained under multitransverse mode operation at 240 K. Under operation in the fundamental near-Gaussian mode, we obtained a maximum power of 230 mW with a beam quality factor (M-2) of 1.22. At room temperature, the output power was limited to 12 mW.
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| 5. |
- Lindberg, H, et al.
(författare)
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Improved spectral properties of an optically pumped semiconductor disk laser using a thin diamond heat spreader as an intracavity filter
- 2005
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 17:7, s. 1363-1365
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Tidskriftsartikel (refereegranskat)abstract
- This letter describes an optically pumped high-power InP-based semiconductor disk laser with a thin (50 mu m) diamond heat spreader bonded to the surface of the gain chip. The diamond heat spreader performs the multiple functions of heat removal, spectral filtering, and wavelength stabilization by utilizing the high thermal conductivity and the low thermooptic coefficient of diamond, along with the large free-spectral range of a thin intracavity etalon. A pump-power-limited output power of 680 mW at 1.55 mu m is demonstrated at a heat sink temperature of -30 degrees C, and 140 mW at room temperature. The spectral width was measured to be less than 0.08 nm and the spectral drift with temperature and pump power as low as 0.03 nm/degrees C and 0.14 nm/W, respectively.
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| 6. |
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| 7. |
- Lindberg, Hans, 1977, et al.
(författare)
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InP-based optically pumped VECSEL operating CW at 1550 nm
- 2004
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 16:2, s. 362-364
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Tidskriftsartikel (refereegranskat)abstract
- We present a vertical external-cavity surface-emitting laser operating at 1550 run. The laser comprises an InGaAsP-based gain element, with a resonant periodic gain structure on top of a distributed Bragg reflector, and a high reflectivity spherical mirror as the external reflector. Optical pumping is achieved using a 1250-nm fiber Raman laser. A maximum continuous output power of 70 mW was obtained under multitransverse mode operation at 233 K. Under single-mode operation, we obtained a maximum power of 60 mW with a beam quality factor M-2 less than 1.1.
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| 8. |
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| 9. |
- Lindberg, H., et al.
(författare)
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Optically pumped VECSEL operating at 1550 nm
- 2004
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. ; , s. 25-33
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Konferensbidrag (refereegranskat)abstract
- We present the design and characteristics of an optically pumped vertical external cavity surface emitting laser emitting near 1550 nm. The InP-based laser was grown by Metalorganic vapor-phase epitaxy including an InGaAsP gain element and an InP/InGaAsP mirror. The gain element comprises 20 strain compensated quantum wells on top of a distributed Bragg reflector. As an external mirror we used a concave spherical mirror, which also provides the outcoupling of light. Gain is achieved by optical pumping with a high power, 1250 nm fiber Raman laser focused on the gain chip. Essential for achieving high output power is to reduce the temperature of the gain material and this is accomplished by bonding an intra-cavity silicon heat spreader to the surface of the gain element. The maximum output power is 260 mW at multi transverse mode operation and 230 mW at single transverse mode operation with a near Gaussian beam profile (M2=1.22) at 240 K. At room temperature the output power was limited to 12 mW. The maximum output power greatly depends on the operating temperature and studies of pump induced thermal effects show that thermal lensing imposes limitations on the attainable power.
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| 10. |
- Lindberg, H, et al.
(författare)
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Single-frequency operation of a high-power, long-wavelength semiconductor disk laser
- 2005
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 30:17, s. 2260-2262
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Tidskriftsartikel (refereegranskat)abstract
- An optically pumped, high-power, single-frequency semiconductor disk laser is demonstrated. A thin (50 mu m) diamond bonded to an InGaAsP gain chip provides the combined functions of heat removal and spectral filtering, thus eliminating the need for the additional intracavity etalons that are usually employed for single-frequency operation. In a short cavity (4 mm) configuration we obtained a maximum output power of 470 mW at 0 degrees C and 170 mW at 20 degrees C in a near-diffraction-limited beam (M-2 < 1.2). The emission wavelength was 1549 nm and the linewidth was less than 200 MHz.
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