Multi-wavelength arbitrary waveform generation through spectro-temporal unitary transformations

TL;DR

This paper introduces a lossless, spectro-temporal transformation method that enables arbitrary, simultaneous modulation of multiple wavelengths, overcoming traditional lossy modulators' limitations in bandwidth and multi-channel processing.

Contribution

It presents a novel spectro-temporal unitary transformation technique using only lossless phase modulation and dispersive filtering, allowing independent, high-bandwidth manipulation of multiple input wavelengths.

Findings

Achieves lossless, arbitrary waveform transformations

Enables simultaneous modulation of multiple spectral channels

Overcomes bandwidth and loss limitations of traditional modulators

Abstract

Temporal waveform manipulation is a fundamental functionality in optics and crucial for applications like optical communications, microwave photonics and quantum optics. Traditional IQ- or phase-amplitude modulators shape light by carving energy from the input lightwave and are thus fundamentally lossy, and cannot apply independent modulation to multiple input wavelengths simultaneously. Taking inspiration from the space-time duality, we produce arbitrary unitary spectro-temporal transformations on multiple temporal input vectors with a modulation structure comprising of only lossless phase modulation and dispersive allpass filtering. The bandwidth of the output waveforms is not restricted by the driving electronics and independent transformations can be performed simultaneously on multiple orthogonal inputs such as spectrally separated frequency tones. This overcomes the main limitations of traditional electro-optic modulators and offers fundamental new insight into temporal wave manipulation.