# Pulse shaping using dispersion-engineered difference frequency generation

## TL;DR

This paper demonstrates a novel, efficient method for pulse shaping using dispersion-engineered difference frequency generation in nonlinear waveguides, enabling high-dimensional quantum encoding with potential advantages over classical methods.

## Contribution

It introduces a new pulse shaping technique based on dispersion-engineered DFG, capable of imprinting pump pulse shapes onto output with high efficiency and reliability.

## Key findings

- Successfully shaped the first five Hermite-Gauss modes
- Established limits of practical pulse shaping operation
- Demonstrated unitary transformation with potential quantum encoding applications

## Abstract

The temporal-mode (TM) basis is a prime candidate to perform high-dimensional quantum encoding. Quantum frequency conversion has been employed as a tool to perform tomographic analysis and manipulation of ultrafast states of quantum light necessary to implement a TM-based encoding protocol. While demultiplexing of such states of light has been demonstrated in the Quantum Pulse Gate (QPG), a multiplexing device is needed to complete an experimental framework for TM encoding. In this work we demonstrate the reverse process of the QPG. A dispersion-engineered difference frequency generation in non-linear optical waveguides is employed to imprint the pulse shape of the pump pulse onto the output. This transformation is unitary and can be more efficient than classical pulse shaping methods. We experimentally study the process by shaping the first five orders of Hermite-Gauss modes of various bandwidths. Finally, we establish and model the limits of practical, reliable shaping operation.