Monolithic 1 × 8 DWDM Silicon Optical Transmitter Using an Arrayed-Waveguide Grating and Electro-Absorption Modulators for Switch Fabrics in Intra-Data-Center Interconnects

Abstract

In this study, we propose an eight-channel monolithic optical transmitter using silicon electro-absorption modulators (EAMs) based on free-carrier injection by Schottky junctions. The transmitter consists of a 1 × 8 silicon arrayed-waveguide grating (AWG) and eight 500-μm-long EAMs on a 5.41 × 2.84 mm2 footprint. It generates eight-channel dense wavelength-division multiplexing (DWDM) outputs with 1.33 nm channel spacing (Δλ) in the C-band from a single broadband light source and modulates each channel with over 3 dB modulation depth at 6 V peak-to-peak. The experimental results showed that the feasibility of a homogeneous silicon DWDM transmitter with a single light source for switch fabrics in intra-data-center interconnects over heterogeneous integration with regards to more complementary metal–oxide–semiconductor (CMOS) compatibility.

Modulators in Silicon Photonics—Heterogenous Integration & and Beyond

“…Nevertheless their small footprint and high absorption will no doubt make them a subject of interest in the coming years. V π • L = ∼4 V•cm Si MRM [13] 30 NA >300 NA V π • L = ∼0.65 V•cm Si MRM [14] 128 50 >300 2.9-4.2 V π • L = 0.52 V•cm Si MRM [17] 25-44 35 >18 29 dB/cm NA Si MZM [31] 28-40 NA NA 6.5 dB/mm V π • L = 2 V•mm Si MZM [32] 52 NA NA 5 1.4-1.9 V/cm Si MZM [33] 60 27.7 NA 3.5 V π • L = 2 V•cm Si EAM [35] 4 GHz 1542-1558 nm NA 51 NA III-V Si MOS [36] NA NA NA NA V π • L = 0.11 V•cm III-V Si MOS [37] NA 100 expected NA 28 dB/cm V π • L = 0.12-0.17 V•cm III-V Si MRM [38] 38 GHz 50 NA NA V π • L = 0.059-0.064 V•cm III-V Si MZM [39] NA NA NA NA V π • L = 0.1 V•cm III-V Si EAM [ [69] 1 GHz NA >80 NA NA DLG on Si [70] 22 NA NA NA f max D dB /(V swing IL dB ) = 3.75 GHz/V DLG on Si [71] 35 GHz 1500-1640 nm 18 0.9 ER/IL = 2/0.9 LiNb0 3 on Si [74] 110 GHz NA NA 15 DC-V π = 9.4 V LN MZM [75] 100-112 * expected NA NA 2.5 V π = 5.1 V BTO MZM [77] 25 NA NA 5.8 dB/cm V π • L = 0.2 V•cm Plasmonic MZM [85] 100…”

“…Jeong et al explores this challenge in a unique manner, incorporating homogeneous EAMs based on the aforementioned free carrier plasma dispersion effect [35]. Jeong utilises a Schottky diode as part of the EAM, achieving optical modulation by the intensity change of the light from the free carrier absorption to change the absorption coefficient, but not conventional interference effects.…”

Tunable Bandpass Filter With Serially Coupled Ring Resonators Assisted MZI

“…I NTEGRATED optical filters are among the most widely used components in photonic circuits. Many optical applications utilize interferometric devices such as Mach-Zehnder Interferometer (MZI) [1], [2], Ring Resonators (RRs) [3]- [7], Bragg or Arrayed Waveguide Gratings (AWGs) [8]- [10], contra-directional couplers [11], [12] and photonic crystal filters [13] for their filtering requirements.…”

“…One common application of optical filters is to isolate frequency channels in wavelength division multiplexed (WDM) networks used in data communication and telecommunication systems [1], [8], [11], [14]. The ever-increasing demand for bandwidth in these systems has brought forward the need for gridless networks, also known as elastic optical networks (EONs), where the channel spacings and bandwidth can be adjusted dynamically.…”