Abstract-We report the operation of a vertical-cavity surfaceemitting laser (VCSEL) with two active, coupled optical cavities. In contrast to a conventional single-cavity VCSEL, the coupling between the two electrically independent active regions produces emission into two longitudinal modes. The light output versus current characteristics are presented under various biasing conditions in each cavity. Laser operation is achieved with current injection into only one cavity, and additional current injected into the other cavity changes the effective threshold current measured. The longitudinal and transverse modes are characterized, and it is found that the modal evolution of the laser can be modified by current injection into each cavity.

A record 9 GHz small signal modulation in a single fundamental mode photonic crystal vertical cavity surface emitting laser is demonstrated for the first time. The device is designed by incorporating etched photonic crystal holes in the top distributed Bragg reflector for optical confinement. Emission spectra measured during small signal modulation confirms single fundamental mode operation.

Abstract-We report the small-signal modulation characteristics of a monolithic dual resonator vertical cavity surface emitting laser. The modulation response is described by a system of rate equations with two independent carrier populations and a single longitudinal optical mode. The independent optical overlaps and differential gains of the two active regions can each be adjusted to maximize the output response. We show that under certain conditions, the composite resonator may achieve a higher bandwidth than a single cavity laser with the same photon density. We find the relaxation oscillation frequency to depend mainly on the total photon density and not the individual currents in the two cavities. With appropriate current injection, the composite resonator laser achieves a maximum 3-dB bandwidth of 12.5 GHz and a maximum modulation current efficiency factor of approximately 5 GHz/ma 1 2 .

The high-speed characteristics of a composite-resonator vertical-cavity laser (CRVCL) under both smalland large-signal electroabsorption modulation are investigated. The maximum 23 dB modulation bandwidth of 12.5 GHz is measured. The theoretical modulation response of the CRVCL is derived from the standard rate equations, and the qualitative form is in agreement with the measured results. The CRVCL under electroabsorption modulation exhibits a promising potential to extend the modulation bandwidth beyond that of a conventional VCSEL. However, the CRVCL under large-signal electroabsorption modulation is limited to low data rates, and the large relaxation oscillation resonance must be suppressed for higher-speed digitaloptical link applications.

Abstract-We demonstrate the use of a dual-resonator verticalcavity laser diode as a coarse wavelength-division-multiplexing optical source. Binary data is encoded onto each of the two longitudinal modes, which can be independently modulated through current injection into each cavity. Using a single laser, we demonstrate data transmission on two independent channels. Index Terms-Composite-resonator vertical-cavity laser (CRVCL), dual-wavelength laser source, vertical-cavity surface-emitting laser (VCSEL), wavelength-division multiplexing (WDM), wavelength-division-multiplexing (WDM) laser source.