# A Time Mode Pulse Interleaver in a Silicon-on-Insulator Platform for Optical Analog-to-Digital Converters

## TL;DR

This paper introduces a compact on-chip optical pulse interleaver for high-speed optical analog-to-digital converters.

## Contribution

A novel time mode pulse interleaver using a single S-shaped waveguide in a silicon-on-insulator platform is proposed and demonstrated.

## Key findings

- The delay waveguide length is reduced by 46.3% compared to prior designs.
- The device generates a 40 GHz pulse sequence with an RMS timing error of 0.9 ps.
- The design eliminates the need for active tuning by using time delay between optical modes.

## Abstract

We propose and demonstrate a novel on-chip optical sampling pulse interleaver based on time mode interleaving. The designed pulse interleaver was fabricated on a 220 nm silicon-on-insulator (SOI) platform, utilizing only one S-shaped delay waveguide. Interleaving is achieved by the relative time delay between different optical modes in the waveguide, eliminating the need for any active tuning. The total length of the delay waveguide is 5620.5 µm, which is reduced by a factor of 46.3% compared with previously reported time-wavelength interleaver schemes. The experimental results indicate that the device can convert an optical pulse into a 40 GHz pulse sequence composed of four pulses with a root mean square (RMS) timing error of 0.9 ps, making it well suited for generating high-frequency sampling pulses for optical analog-to-digital converters.