Electro-absorption modulator and monolithic electro-photonic integrated circuit comprising an electro-absorption modulator and driver electronics

A waveguide (WG)-device configured to modulate light and comprising a p-type material, an i-type material and an n-type material (a PIN waveguide), the waveguide-device comprising:

• a semi-insulating (SI) indium phosphide (InP) substrate;
• an epitaxial layer stack formed on the SI InP substrate structured to form the PIN waveguide, the epitaxial layer stack comprising:
• an n-layer structure of n-type material and a p-layer structure of p-type material;
• and
• an i-region of i-type material comprising absorption material having an operational wavelength range and a Quantum Confined Stark Effect (QCSE) multi-quantum well (MQW) structure selected to comprise N wells and N−1 barriers, the i-region located between the n-layer structure and the p-layer structure;
• wherein the n-layer structure and the p-layer structure are arranged to optical confine one or more modes of an optical signal to propagate through the i-region;
• wherein N is between ≥8 and ≤24;
• and a ratio of a barrier thickness to a well thickness is <1:1, to:
• reduce a thickness d of the i-region by an amount based on said ratio;
• and
• reduce a transit time limit ttr of carriers in the i-region, where ttr=d/v, and v is a carrier velocity of the carrier;
• and
• wherein the waveguide has a balance of materials or dimensions to provide one or more of:
• a dynamic extinction ratio (ER) substantially of ≥3.5 dB;
• and
• a device capacitance of substantially ≤0.85 fF/μm.