107 Gb/s Ultra-High Speed, Surface-Normal Electroabsorption Modulator Devices

Short reach communication systems, such as datacenters and access networks, exhibit steep capacity growth and require opto-electronic technologies with small size, low complexity, and low power consumption. Here, we demonstrate large-scale arrays of reflective surface normal electroabsorption modulators (SNEAMs). With very small active volumes, SNEAMs enable ultra-wide electro-optic bandwidth (>>65 GHz). We show modulation at 25 Gbit/s with 1 Vpp drive voltage on packaged SNEAMs and ultra-high bit-rate modulation at 107 Gbit/s with bare chips. These modulators are polarization-independent and have very low total input/output coupling loss of 0.7 dB to single-mode-fibers. We package SNEAM arrays with arrayed waveguide gratings into wavelength division multiplexing transmitters. Due to their broad wavelength range of modulation, SNEAMs do not need power hungry wavelength tuning or locking systems. Future co-integration of SNEAM arrays with low-power electronic driver arrays will enable high-capacity, low-power electro-optic engines.

I. Introduction

Optical modulators are fundamental components of today's telecommunications networks, that enable the conversion of high-speed electrical signals to the optical domain [1]–[6]. Typically, the modulator type and the materials platform depend on the modulation quality and transmission distance required by the communication system. For instance, Mach-Zehnder modulators (MZMs) [1]–[4], [6], that employ a waveguide interferometer to convert a phase modulation into amplitude modulation, enable an almost ideal form of modulation, with very high extinction ratio and no residual chirp. In addition, multiple MZMs can be integrated together [7] to implement advanced modulation formats, and hence transmit signals on both polarizations, in-phase and quadrature, and on different amplitude levels. The complexity and transmission capacity that can be achieved in this way well meet the requirements of coherent optical communications used in metro and long-haul systems.