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Recent advances in high-contrast grating (HCG) vertical-cavity surface-emitting lasers (VCSEL) emitting at 1550 nm is reported in this paper. The novel near-wavelength HCG has an ultrathin structure and broadband reflectivity. It enables a monolithic, simple fabrication process for realizing InP-based VCSELs emitting at ∼1550 nm. We report 2.4-mW single-mode output under continuous-wave operation at 15 °C. We show that, despite broadened by the Brownian motion, the HCG-VCSEL has a total linewidth of 60 MHz or a coherent length of 5 m in air, and an intrinsic linewidth <20 MHz. Transmission of directly modulated 10 Gbps over 100-km dispersion-compensated single-mode fiber is demonstrated. Tunable HCG-VCSEL is demonstrated with the HCG integrated with a micro-electro-mechanical structure. Continuous wavelength tuning as wide as 26.3 nm is achieved. The tunable VCSEL was used as a source for external modulation for 40-Gbps differential-phase-shift-keyed signal and transmitted over 100-km dispersion-compensated link with negligible power penalty. [ABSTRACT FROM PUBLISHER]

Semiconductor diode lasers can be used in a variety of applications including telecommunications, displays, solid-state lighting, sensing and printing. Among them, vertical-cavity surface-emitting lasers (VCSELs) are particularly promising. Because they emit light normal to the constituent wafer surface, it is possible to extract light more efficiently and to fabricate two-dimensional device arrays. A VCSEL contains two distributed Bragg reflector (DBR) mirrors for optical feedback, separated by a very short active gain region. Typically, the reflectivity of the DBRs must exceed 99.5% in order for the VCSEL to lase. However, the realization of practical VCSELs that can be used over a broad spectrum of wavelengths has been hindered by the poor optical and thermal properties of candidate DBR materials. In this Letter, we present surface-emitting lasers that incorporate a single-layer high-index-contrast subwavelength grating (HCG). The HCG provides both efficient optical feedback and control of the wavelength and polarization of the emitted light. Such integration reduces the required VCSEL mirror epitaxial thickness by a factor of two and increases fabrication tolerance. This work will directly influence the future designs of VCSELs, photovoltaic cells and light-emitting diodes at blue–green, 1.3–1.55 µm and mid- to far-infrared wavelengths. [ABSTRACT FROM AUTHOR]

We have designed and fabricated a subwavelength grating (SWG) broadband mirror whose performance depends on key factors, including SWG period, duty cycle, and angle of incident light. The fabricated SWGs exhibit high reflectivity (>=96%), when the grating periods are varied from 650 to 750 nm and duty cycles are varied from 55% to 65%. The bandwidth and reflectivity of these mirrors are remarkably robust to variations in design and fabrication. The SWGs can be designed as broadband mirrors from microwave to visible wavelengths. [ABSTRACT FROM AUTHOR]