| 1. |
- Haglund, Erik, 1985, et al.
(författare)
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Demonstration of post-growth wavelength setting of VCSELs using high-contrast gratings
- 2016
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Ingår i: Optics Express. - : The Optical Society. - 1094-4087 .- 1094-4087. ; 24:3, s. 1999-2005
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate, for the first time, post-growth wavelength setting of electrically-injected vertical-cavity surface-emitting lasers (VCSELs) by using high-contrast gratings (HCGs) with different grating parameters. By fabricating HCGs with different duty cycle and period, the HCG reflection phase can be varied, in effect giving different optical cavity lengths for HCG-VCSELs with different grating parameters. This enables fabrication of monolithic multi-wavelength HCG-VCSEL arrays for wavelength-division multiplexing (WDM). The GaAs HCG is suspended in air by removing a sacrificial layer of InGaP. Electrically-injected 980-nm HCG-VCSELs with sub-mA threshold currents indicate high reflectivity from the GaAs HCGs. Lasing over a wavelength span of 15 nm was achieved, enabling a 4-channel WDM array with 5 nm channel spacing. A large wavelength setting span was enabled by an air-coupled cavity design and the use of only the HCG as top mirror.
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| 2. |
- Haglund, Erik, 1985, et al.
(författare)
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Multi-wavelength VCSEL arrays using high-contrast gratings
- 2017
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9781510606678 ; 10113
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Konferensbidrag (refereegranskat)abstract
- The use of a high-contrast grating (HCG) as the top mirror in a vertical-cavity surface-emitting laser (VCSEL) allows for setting the resonance wavelength by the grating parameters in a post-epitaxial growth fabrication process. Using this technique, we demonstrate electrically driven multi-wavelength VCSEL arrays at ∼980 nm wavelength. The VCSELs are GaAs-based and the suspended GaAs HCGs were fabricated using electron-beam lithography, dry etching and selective removal of an InGaP sacrificial layer. The air-coupled cavity design enabled 4-channel arrays with 5 nm wavelength spacing and sub-mA threshold currents thanks to the high HCG reflectance.
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| 3. |
- Larsson, Anders, 1957, et al.
(författare)
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1060 nm VCSELs for long-reach optical interconnects
- 2018
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Ingår i: Optical Fiber Technology. - : Elsevier BV. - 1095-9912 .- 1068-5200. ; 44, s. 36-42
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Tidskriftsartikel (refereegranskat)abstract
- Reach extension of high capacity optical interconnects based on vertical-cavity surface-emitting lasers (VCSELs) and multimode fibers (MMFs), as needed for large-scale data centers, would benefit from high-speed GaAs-based VCSELs at 1060 nm. At this wavelength, the chromatic dispersion and attenuation of the optical fiber are much reduced in comparison with 850 nm. We present single and multimode 1060 nm VCSELs based on designs derived partly from our high-speed 850 nm VCSEL designs. The single-mode VCSEL, with a modulation bandwidth exceeding 22 GHz, supports back-to-back data rates up to 50 Gbps at 25 °C and 40 Gbps at 85 °C under binary NRZ (OOK) modulation. Using mode-selective launch, we demonstrate error-free 25 Gbps transmission over 1000 m of 1060 nm optimized MMF. Higher data rates and/or longer distances will be possible with equalization, forward-error-correction, and/or multilevel modulation.
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| 4. |
- Lengyel, Tamas, 1986, et al.
(författare)
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Pre-emphasis enabled 50 Gbit/s transmission over 1000 m SMF using a 1060 nm single-mode VCSEL
- 2018
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 54:20, s. 1186-1187
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Tidskriftsartikel (refereegranskat)abstract
- A single-mode 1060 nm vertical-cavity surface-emitting laser (VCSEL) and single-mode fibre (SMF) based link with two-tap active pre-emphasis enabling error-free transmission of 50 Gbit/s NRZ-OOK over 1000 m is presented.
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| 5. |
- Simpanen, Ewa, 1987, et al.
(författare)
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1060 nm Single-Mode VCSEL and Single-Mode Fiber Links for Long-Reach Optical Interconnects
- 2019
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 37:13, s. 2963-2969
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the use of a 1060 nm single-mode vertical-cavity surface-emitting laser (VCSEL) and a 1060 nm single-mode fiber as a competitive single-mode technology for cost-and power-efficient long-reach optical interconnects. Error-free transmission (bit error rate < 10-12) over 2 km is demonstrated at bitrates up to 40 Gb/s under on-off keying non-return-to-zero (OOK-NRZ) modulation, without equalization, forward-error correction, or other forms of digital signal processing. The VCSEL is extensively characterized with respect to its static and dynamic performances, including the power-voltage-current characteristics, spectral characteristics, beam divergence, modulation response, relative intensity noise, and frequency chirp. The measured dependence of power penalty on fiber length is consistent with an analysis of chirp-induced pulse compression and broadening along the negative chromatic dispersion fiber.
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| 6. |
- Simpanen, Ewa, 1987, et al.
(författare)
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1060 nm single-mode vertical-cavity surface-emitting laser operating at 50 Gbit/s data rate
- 2017
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 53:13, s. 869-870
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Tidskriftsartikel (refereegranskat)abstract
- An energy efficient 1060 nm GaAs-based oxide-confined vertical-cavity surface-emitting laser designed for high-speed modulation and singlemode emission has been developed. A record data rate of 50 Gbit/ s at an energy dissipation of 100 fJ/ bit is demonstrated for a device with > 50 dB side-mode-suppression and 0.2 mA threshold current, making this laser a promising light source for long-reach optical interconnects.
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| 7. |
- Simpanen, Ewa, 1987, et al.
(författare)
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Noise Performance of Single-Mode VCSELs: Dependence on Current Confinement and Optical Loss
- 2020
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Ingår i: IEEE Journal of Quantum Electronics. - 0018-9197 .- 1558-1713. ; 56:5
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the intensity and phase noise properties of GaAs-based 1060 nm oxide-confined single-mode vertical-cavity surface-emitting lasers (VCSELs) and their dependence on slope efficiency and current spreading, parameters that control the achievable output power. We find strong dependence of the linewidth on slope efficiency because it affects the optical resonator loss and therefore the spontaneous emission rate and the photon density. Likewise, we find strong dependence of the relative intensity noise on the slope efficiency since the optical resonator loss controls the photon lifetime, and therefore the damping of the relaxation oscillations. There is no noticeable dependence on transverse current confinement and current spreading. We measure linewidths as small as 6 MHz which we attribute to a small linewidth enhancement factor. This assumption is supported by calculations of the linewidth enhancement factor from optical resonator and optical gain simulations. The dependencies of noise on design parameters are general and therefore valid for single-mode VCSELs at other wavelengths and in other material systems.
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