Alexandru Mereuta

1.5-mW single-mode operation of wafer-fused 1550-nm VCSELs

We demonstrate 1.5-/spl mu/m waveband wafer-fused InGaAlAs-InP-AlGaAs-GaAs vertical-cavity surface-emitting lasers (VCSELs) emitting high single-mode power of 1.5 mW at room temperature with sidemode suppression ratio of over 30 dB and a full-width at half-maximum far field angle of 9/spl deg/. These devices have thermal resistance value below 1.5 K/mW and are emitting 0.2 mW at 70/spl deg/C. VCSELs with a wavelength span of 40-nm emission are produced from the same active cavity material, which shows the potential of realizing multiple-wavelength VCSEL arrays.

High-performance single-mode VCSELs in the 1310-nm waveband

High-performance vertical-cavity surface-emitting lasers (VCSELs) emitting in the 1310-nm waveband are fabricated by bonding AlGaAs-GaAs distributed Bragg reflectors on both sides of a InP-based cavity. A 2-in wafer bonding process is optimized to produce very good on-wafer device parameter uniformity. Carrier injection is implemented via double intracavity contact layers and a tunnel junction. A 1.2-mW single-mode output power is obtained in the temperature range of 20/spl deg/C-80/spl deg/C. Modulation capability at 3.2 Gb/s is demonstrated up to 70/spl deg/C. Overall VCSEL performance complies with the requirements of the 10 GBASE-LX4 IEEE.802.3ae standard, which opens the way for novel applications of VCSELs emitting in the 1310-nm band.

2.6 W optically-pumped semiconductor disk laser operating at 1.57-µm using wafer fusion

We report a wafer fused high power optically pumped semiconductor disk laser incorporating InP-based active medium fused to a GaAs/AlGaAs distributed Bragg reflector. A record value of over 2.6 W of output power in a spectral range around 1.57 microm was demonstrated, revealing the essential advantage of the wafer fusing technique over monolithically-grown all-InP-based structures. The presented approach allows for integration of lattice-mismatched compounds, quantum-well and quantum-dot based media. This would provide convenient means for extending the wavelength range of semiconductor disk lasers.

Cavity Mode—Gain Peak Tradeoff for 1320-nm Wafer-Fused VCSELs With 3-mW Single-Mode Emission Power and 10-Gb/s Modulation Speed Up to 70

Room-temperature cavity mode red-shift of about 45nm from the photoluminescence peak is found to be optimal for tradeoff between high modulation bandwidth and good high-temperature performance for InAlGaAs(InP)-AlGaAs fused vertical-cavity surface-emitting lasers (VCSELs) employing tunnel junction carrier injection. Single-mode output power up to 5.4 and 3.1 mW, at 25 degC and 75 degC, respectively, and open eye diagrams exhibiting fall time values close to 40 ps at 10-Gb/s modulation up to at least 70 degC have been obtained for such VCSELs emitting at 1320-nm wavelength

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A widely-tunable single-mode 1.3 μm vertical-cavity surface-emitting laser structure incorporating a microelectromechanical system-tunable high-index-contrast subwavelength grating (HCG) mirror is suggested and numerically investigated. A linear tuning range of 100 nm and a wavelength tuning efficiency of 0.203 are predicted. The large tuning range and efficiency are attributed to the incorporation of the tuning air gap as part of the optical cavity and to the use of a short cavity structure. The short cavity length can be achieved by employing a HCG design of which the reflection mechanism does not rely on resonant coupling. The absence of resonance coupling leads to a 0.59 λ-thick penetration depth of the HCG and enables to use a 0.25 λ-thick tuning air gap underneath the HCG. This considerably reduces the effective cavity length, leading to larger tuning range and efficiency. The basic properties of this new structure are analyzed, and shown to be explained by analytical expressions that are derived in the paper. In this context, the penetration depth of the HCG is introduced and shown to be an important characteristic length scale. Throughout the tuning wavelength range, strong single mode operation was maintained and uniform output power is expected.

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We report a wafer-fused high power optically-pumped semiconductor disk laser operating at 1.3 µm. An InP-based active medium was fused with a GaAs/AlGaAs distributed Bragg reflector, resulting in an integrated monolithic gain mirror. Over 2.7 W of output power, obtained at temperature of 15 °C, represents the best achievement reported to date for this type of lasers. The results reveal an essential advantage of the wafer fusing technique over both monolithically grown AlGaInAs/GaInAsP- and GaInNAs-based structures.

Broadband MEMS-Tunable High-Index-Contrast Subwavelength Grating Long-Wavelength VCSEL

3 W at genuine red wavelength of 650 nm has been achieved from a semiconductor disk laser by frequency doubling. An InP based active medium was fused with a GaAs/AlGaAs distributed Bragg reflector resulting in an integrated monolithic gain mirror. 6.6 W of output power at the fundamental wavelength of 1.3 µm represents the best achievement reported to date for this type of lasers.

1.3-µm optically-pumped semiconductor disk laser by wafer fusion

A new generation of 10 Gb/s wafer fused VCSELs show high single mode output in excess of 2 mW at 80°C (6 mW at 20°C) in the 1310 nm band and 1.5 mW at 80°C (4 mW at 20°C) in the 1550 nm band. Error free transmission over 10 km of standard single mode fiber was performed with less than 1 dB penalty.

3 W of 650 nm red emission by frequency doubling of wafer-fused semiconductor disk laser

A mode-locked Raman fiber laser pumped by 1.3 µm semiconductor disk laser is demonstrated. Direct Watt-level core-pumping of the single-mode fiber Raman lasers and amplifiers with low-noise disk lasers is demonstrated to represent a highly practical solution as compared with conventional scheme using pumping by Raman wavelength convertors. Raman laser employing passive mode-locking by nonlinear polarization evolution in normal dispersion regime produces stable pedestal-free 1.97 ps pulses at 1.38 µm. Using semiconductor disk lasers capable of producing high power with diffraction-limited beam allows Raman gain to be obtained at virtually any wavelength of interest owing to spectral versatility of semiconductor gain materials and wafer-fusing technology.

10 Gbps VCSELs with High Single Mode Output in 1310nm and 1550 nm Wavelength Bands

Record fundamental mode output power of 8mW at 0°C and 6.5mW at room temperature is achieved with wafer-fused VCSELs incorporating regrown tunnel junction and emitting at the 1550nm waveband.