(Color online) (i) Schematic cross section of UIUC microcavity VCSEL device. (ii) The microcavity shows the allowed optical modes: (a) first-order mode, (b) second-order mode, and (c) third-order mode.
(Color online) L–I and I–V curves for three different diameter devices at 25°C. The aperture sizes for three devices are: dA = 2 μm for D1, dA = 2.5 μm for D2, and dA = 3.5 μm for D3.
Optical spectra of a microcavity VCSEL device (ITH = 0.13 mA) at different bias currents. The fundamental mode is labeled (a) (as shown in Fig. 1), with the second-order mode (b) at 2.45 nm longer wavelength and 32.5 dB suppression. The third-order mode intensity is too weak to be recorded.
(Color online) Side Mode Suppression Ratio (SMSR) versus bias current for three different microcavity VCSEL devices: (1) D1 with mode spacing (MS) Δλ ∼ 2.45 nm, (2) D2 with Δλ ∼ 1.6 nm, and (3) D3 with Δλ ∼ 1.0 nm. The smaller the aperture, the larger Δλ and the smaller the threshold current, as well as the larger the SMSR slope before lasing.
(Color online) (i) Temperature dependence of the L–I–V curves for = D2 (dA = 2.5 μm), (ii) Measured and fitting results of temperature-dependent threshold current for the D1, D2, and D3 microcavity lasers.
Microcavity laser fundamental mode wavelength, λ(1,1), versus injection current for D2 device (dA = 2.5 μm) at different temperatures ranging from 15°C to 85°C. The measured dλ/dT is 0.057 nm/oC and dλ/dI is 0.49 nm/mA.
(Color online) Frequency response of 3 μm and 7 μm microcavity VCSEL devices at various bias currents: (a) 3μm device is biased at current I = 0.25, 0.5, 1.0 mA, and −3 dB bandwidth f −3dB = 15.8 GHz at 1mA with resonance peak of 5.8 dB. (b) 7 μm device at various bias currents, and −3 dB bandwidth f −3dB = 12.4 GHz at 4 mA with resonance peak of 14.7 dB.
(Color online) A −3 dB frequency (f −3dB) versus (I−ITH )1/2 comparison of 3 μm and 7 μm microcavity lasers, the slope for the Modulation Current Efficiency Factor (MCEF) is 17.47 GHz/mA1/2 and 6.76 GHz/mA1/2 for the 3 μm and 7 μm devices, respectively.
(Color online) Eye diagrams of 3 μm and 7 μm microcavity lasers at 10Gb/s: (a) 3 μm aperture diameter device at bias current I = 0.5 mA; (b) 7 μm aperture diameter device at bias current I = 4 mA.
(Color online) Eye diagrams of 3 μm and 7 μm microcavity lasers at 13.5 Gb/s: (a) 3 μm aperture diameter device at bias current I = 1 mA; (b) 7 μm aperture diameter device at bias current I = 4 mA.
(Color online) Typical diode VCSEL microcavity lasers with the equivalent intrinsic and extrinsic RC parameters identified as follows: Rj , intrinsic junction resistance; C dep, extrinsic depletion capacitance; C diff, intrinsic diffusion capacitance; Rs , p-type DBR series resistance (with oxide confinement); Rn , n-type DBR series resistance (without oxide confinement); Cp and Rp are extrinsic pad capacitance and resistance. Ca is the extrinsic series capacitance of Cox and Cdep for modeling convenience. The intrinsic part of the laser operation is identified by the dashed line (red) rectangle.
(Color online) Measured optical response, S21, of 3 μm aperture diameter microcavity laser and model fitting as well as the model-projected optical response f− 3dB ∼ 20 GHz at I = 1 mA with a reduced device parasitic capacitance Cp/4, and resistances (Rn+Rs)/2.
Microcavity VCSEL optical mode dimension, d 0, at bias current I = 0.8 mA.
Microcavity VCSEL Purcell enhancement factor FP at bias I = 0.1 mA.
Microcavity VCSEL temperature characteristics.
Parameters for a small signal model of the microcavity VCSEL.
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