Abstract-Single-mode 1.5-µm InP-based vertical-cavity surface-emitting lasers (VCSELs) with a 1.5-λ long semiconductor cavity and two dielectric distributed Bragg reflectors (DBRs) are presented. The electrical, thermal and optical characteristics are studied as a function of tunnel junction diameter and for different temperatures ranging from -10°C up to 65°C. Small-signal modulation bandwidths in excess of 21 GHz at room temperature are demonstrated for a DC power consumption below 10 mW. In this paper, the superior dynamic characteristics of these VCSELs are shown by demonstrating error-free operation at data rates up to 50 Gb/s in back-to-back configuration by non-return-to-zero modulation and without any equalization. Neither forward error correction nor digital signal processing were required.

Abstract-High speed optical interconnects require low-power compact electro-optical transmit modules comprising driver circuits and optical modulators. This paper presents a low power 56 Gb/s non-return-to-zero CMOS inverter based driver in 28 nm fully depleted silicon-on-insulator CMOS driving a 46 GHz silicon photonic microring modulator. The driver delivers 1 Vpp to the microring modulator from a 75 mVpp input while only consuming 40 mW (710 fJ/bit at 56 Gb/s). The realized transmitter shows 4 dB extinction ratio when running of a 1 V supply voltage. Transmission experiments up to 2 km of single mode fiber show a bit-error-ratio less than 1 · 10

Long-wavelength vertical-cavity surface-emitting lasers (LW-VCSELs) with emission wavelength in the 1.3-µm region for intensity modulation (IM)/direct detection optical transmissions enable longer fiber reach compared to C-band VCSELs, thanks to the extremely low chromatic dispersion impact at that wavelength. A lot of effort has been recently dedicated to novel cavity designs in order to enhance LW-VCSELs' modulation bandwidth to allow higher data rates. Another approach to further improve VCSEL-based IM speed consists of making use of dedicated driver circuits implementing feedforward equalization (FFE). In this paper, we present a transmitter assembly incorporating a fourchannel 0.13-µm SiGe driver circuit wire-bonded to a novel dual 1.3-µm VCSEL array. The short-cavity indium phosphide buried tunnel junction VCSEL design minimizes both the photon lifetime and the device parasitic currents. The integrated driver circuit requires 2.5-V supply voltage only due to the implementation of a pseudobalanced regulator; it includes a two-tap asymmetric FFE, where magnitude, sign, relative delay, and pulse width distortion of the taps can be modified. Through the proposed transmitter, standard single-mode fiber reach of 20 and 4.5 km, respectively, for 28-and 40-Gb/s data rate has been demonstrated with stateof-the-art power consumption. Transmitter performance has been analyzed through pseudorandom bit sequences of both 2 7 −1 and 2 31 −1 length, and the additional benefit due to the use of the driver circuit has been discussed in detail. A final comparison with stateof-the-art VCSEL drivers is also includedt.

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