Co-integrated 13µm hybrid III-V/silicon tunable laser and silicon Mach-Zehnder modulator operating at 25Gb/s

Abstract

In this paper, the 200mm silicon-on-insulator (SOI) platform is used to demonstrate the monolithic co-integration of hybrid III-V/silicon distributed Bragg reflector (DBR) tunable lasers and silicon Mach-Zehnder modulators (MZMs), to achieve fully integrated hybrid transmitters for silicon photonics. The design of each active component, as well as the fabrication process steps of the whole architecture are described in detail. A data transmission rate up to 25Gb/s has been reached for transmitters using MZMs with active lengths of 2mm and 4mm. Extinction ratios of respectively 2.9dB and 4.7dB are obtained by applying drive voltages of 2.5V peak-to-peak on the MZMs. 25Gb/s data transmission is demonstrated at 1303.5nm and 1315.8nm, with the possibility to tune the operating wavelength by up to 8.5nm in each case, by using metallic heaters above the laser Bragg reflectors.

Ultra-Low-Loss Silicon Waveguides for Heterogeneously Integrated Silicon/III-V Photonics

“…In most heterogeneous silicon/III-V photonic lasers, current is injected vertically through the III-V active region and thus the III-V stack is typically about 2 µm thick to separate the contact metal sufficiently far from the optical mode. As a result, the silicon thickness must also be as thick as 400~500 nm to match the refactive index of the III-V slab for an efficient mode hybrization in the Si/III-V waveguides [23]. The heterogeneous Si/III-V photonic design kit (PDK) developed at UCSB at 1550 nm wavelength in recent years has been built and optimized for 500 nm thick silicon on 1 µm buried oxide on silicon substrates.…”

Directly Modulated Single‐Mode Tunable Quantum Dot Lasers at 1.3 µm

“…Currently, the most common tunable lasers come in the form of either ring‐based lasers, distributed Bragg reflector (DBR) lasers, including those integrated on Si through wafer bonding, sampled‐grating distributed Bragg reflectors (SGDBR), or digital super‐mode DBRs that are fabricated through multiple regrowth steps on native substrates. In addition to fabrication complexity, nonuniform gratings, and multiple epitaxial growths that degrade the fabrication yield, these types of lasers possess relatively large footprint and complex control algorithms for wavelength tuning with multiple electrodes.…”

“…[4] In future DWDM systems, a widely tunable laser is one of the key components that provides dynamic wavelength management in high-traffic networks and has the additional advantage of allowing a common component stocking for inventory cost-saving and increased flexibility in building optical networks. [5] Currently, the most common tunable lasers come in the form of either ring-based lasers, [6,7] distributed Bragg reflector (DBR) lasers, [8,9] including those integrated on Si through wafer bonding, sampled-grating distributed Bragg reflectors (SGDBR), [10] or digital super-mode DBRs [11] that are fabricated through multiple regrowth steps on native substrates. In addition to fabrication complexity, nonuniform gratings, and multiple epitaxial growths that degrade the fabrication yield, these types of lasers possess relatively large footprint and complex control algorithms for wavelength tuning with multiple electrodes.…”

Ultra-Low-Loss Silicon Waveguides for Heterogeneously Integrated Silicon/III-V Photonics

“…However, the high index contrast also results in more scattering loss, especially in waveguide with small cross-sectional mode area. For the best performances of optical amplifiers and lasers on the Si/III-V platform, the silicon thickness is optimally chosen in the range of 400-500 nm as discussed in detail in [13,14] and Section 2 below. With SOI thickness in the sub-micron range, typical propagation loss of single-mode Si waveguides ranges from 0.5 dB/cm to 2 dB/cm [15][16][17], and the lower number requires best-in-class immersion 193 nm lithography.…”