We have achieved continuous-wave (CW) operation of an optically polarized m-plane GaN-based vertical-cavity surface-emitting laser (VCSEL) with an ion implanted current aperture, a tunnel junction intracavity contact, and a dual dielectric distributed Bragg reflector design. The reported VCSEL has 2 quantum wells, with a 14 nm quantum well width, 1 nm barriers, a 5 nm electron-blocking layer, and a 23λ total cavity thickness. The thermal performance was improved by increasing the cavity length and using Au-In solid-liquid interdiffusion bonding, which led to lasing under CW operation for over 20 min. Lasing wavelengths under pulsed operation were observed at 406 nm, 412 nm, and 419 nm. Only the latter two modes appeared under CW operation due to the redshifted gain at higher temperatures. The peak output powers for a 6 μm aperture VCSEL under CW and pulsed operation were 140 μW and 700 μW, respectively. The fundamental transverse mode was observed without the presence of filamentary lasing. The thermal impedance was estimated to be ∼1400 °C/W for a 6 μm aperture 23λ VCSEL.

We report the first demonstration of III-nitride vertical-cavity surface-emitting lasers (VCSELs) with tunnel junction (TJ) intracavity contacts grown completely by metal-organic chemical vapor deposition (MOCVD). For the TJs, n ++ -GaN was grown on in-situ activated p ++ -GaN after buffered HF surface treatment. The electrical properties and epitaxial morphologies of the TJs were first investigated on TJ LED test samples. A VCSEL with a TJ intracavity contact showed a lasing wavelength of 408 nm, a threshold current of >15 mA (10 kA/cm 2 ), a threshold voltage of 7.8 V, a maximum output power of 319 µW, and a differential efficiency of 0.28%.

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The dynamic characteristics of III-nitride multi-quantum well laser diodes (LDs) emitting at 410 nm were investigated. LDs were grown on semipolar (202¯1¯) bulk GaN substrates and fabricated into devices with cavity lengths ranging from 900 nm to 1800 nm. A 3-dB bandwidth of 5 GHz and 5 Gbit/s direct modulation with on-off keying were demonstrated, which were limited by the bandwidth of the photodetector used for the measurements. The differential gain of the LDs was determined to be 2.5 ± 0.5 × 10−16 cm2 by comparing the slope efficiency for different cavity lengths. Analysis of the frequency response showed that the K-factor, the gain compression factor, and the intrinsic maximum bandwidth were 0.33 ns, 7.4 × 10−17 cm3, and 27 GHz, respectively.

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