I-Chen Hsu

Characteristics of InGaAs Submonolayer Quantum-Dot and InAs Quantum-Dot Photonic-Crystal Vertical-Cavity Surface-Emitting Lasers

We have made InGaAs submonolayer (SML) quantum-dot (QD) and InAs QD photonic-crystal vertical-cavity surface-emitting lasers (PhC-VCSELs) for fiber-optic communications in the 990 and 1300 nm ranges, respectively. The active region of the InGaAs SML QD PhC-VCSEL contains three InGaAs SML QD layers, with each of the SML QD layer formed by alternating depositions of InAs and GaAs. The active region of the InAs QD PhC-VCSEL contains 17 undoped InAs-InGaAs QD layers. Both types of QD PhC-VCSELs exhibit single-mode characteristics throughout the current range, with side-mode suppression ratio (SMSR) larger than 35 dB. A maximum output power of 5.7 mW has been achieved for the InGaAs SML QD PhC-VCSEL. The near-field image study of the QD PhC-VCSELs indicates that the laser beam is well confined by the photonic-crystal structure of the device.

Single-mode InGaAs submonolayer quantum dot photonic crystal VCSELs

An InGaAs submonolayer (SML) quantum dot photonic crystal vertical-cavity surface-emitting laser (QD PhC-VCSEL) for fibre-optic applications is demonstrated for the first time. The active region of the device contains three InGaAs SML QD layers. Each of the InGaAs SML QD layers is formed by alternate deposition of InAs (<1 ML) and GaAs. Single-fundamental-mode CW output power of 3.8 mW at 28 mA has been achieved in the 990 nm range, with a threshold current of 0.9 mA. A side-mode suppression ratio (SMSR) larger than 35 dB has been observed over the entire current operating range.

High-Power Single-Mode Vertical-Cavity Surface-Emitting Lasers with Multi-Leaf Holey Structure

A single-mode oxide-confined vertical-cavity surface-emitting laser (VCSEL) with multi-leaf holey structure for fiber-optic applications is demonstrated. Single fundamental mode continuous-wave output power of over 3 mW has been achieved in the 850 nm range, with a threshold current of approximately 0.5 mA. Side-mode suppression ratio (SMSR) larger than 22 dB has been measured.

Characteristics of Cross-Shaped Polarization-Switching Vertical-Cavity Surface-Emitting Lasers for Dual-Channel Communications

The polarization switching of a cross-shaped vertical-cavity surface-emitting laser (VCSEL) for dual-channel communications is demonstrated. The polarization of the lasing output is controlled by the asymmetry in geometry of the device and direction of current injection. High output power ratio of over 5, between two orthogonal (perpendicular) polarization directions has been achieved. The lasing output of the device can be switched between two nearly orthogonal directions.

Characteristics of Single-Mode InGaAs Submonolayer Quantum-Dot Photonic-Crystal Vertical-Cavity Surface-Emitting Lasers

An InGaAs submonolayer (SML) quantum-dot photonic-crystal vertical-cavity surface-emitting laser (QD PhC-VCSEL) for fiber-optic applications is demonstrated for the first time. The active region of the device contains three InGaAs SML QD layers. Each of the InGaAs SML QD layers is formed by alternate depositions of InAs (<1 ML) and GaAs. A single-fundamental-mode CW output power of 3.8 mW at 28 mA has been achieved in the 990 nm range, with a threshold current of 0.9 mA. A side-mode suppression ratio (SMSR) larger than 35 dB has been demonstrated over the entire current operation range. The beam profile and near-field image study of the PhC-VCSEL indicates that the laser beam is well confined by the photonic crystal structure of the device.

Highly Strained InGaAs/GaAs Quantum Well Vertical-Cavity Surface-Emitting Lasers

We report our results on the highly strained InGaAs/GaAs quantum well (QW) vertical-cavity surface-emitting lasers (VCSELs) in the 1140 to 1250 nm range. The epitaxial structures were grown on (100)GaAs substrates by metal-organic chemical vapor deposition (MOCVD). A maximum output power of more than 6.3 mW has been demonstrated. The spectral characteristics were also measured and analyzed.

Characteristics of broad-area InGaAs submonolayer quantum-dot vertical-cavity surface-emitting lasers

A broad-area InGaAs submonolayer (SML) quantum-dot vertical-cavity surface-emitting laser (QD VCSEL) for fiber-optic applications is demonstrated. The active region of the device contains three InGaAs SML QD layers. Each of the InGaAs SML QD layers is formed by alternate depositions of InAs (<1 ML) and GaAs. A maximum CW output power of 12.2 mW at 30 mA has been achieved in the 990 nm range, with a threshold current of 1 mA.

Polarization-switching VCSELs for dual-channel communications

We have made cross-shaped polarization-switching VCSELs for dual-channel optical communications. The polarization of the device is controlled by its asymmetry in geometry and current injection. High switching power ratio of over 20 between two polarization states has been achieved.

Single mode InGaAs photonic crystal vertical-cavity surface-emitting lasers

We have made MOCVD-grown InGaAs photonic crystal vertical-cavity surface-emitting lasers (PhC-VCSELs) for fiber-optic applications. Multi-mode InGaAs VCSELs have achieved a maximum power of over 1 mW. Single-mode characteristics of 0.18 mW of the PhC-VCSELs have been made by using the combined AlOx oxide layer with proton-implantion for better current confinement.

High-Power Single Mode InGaAs Sub-Monolayer Quantum-Dot Photonic-Crystal VCSELs

An InGaAs sub-monolayer (SML) quantum dot photonic crystal vertical-cavity surface-emitting laser (QD PhC-VCSEL) for fiber-optic applications is first demonstrated. Single fundamental mode CW output power of 3.8 mW has been achieved in the 990 nm range, with a threshold current of 1 mA. SMSR larger than 35 dB has been observed over entire operation range