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Serrodyne Frequency Shift Spectrometer and Serrodyne Frequency Shifting

Published Patent Application Number: WO 2024/130243

Problem

A schematic of the single-modulator, direct frequency comb spectrometer. Abbreviations are: direct digital synthesizer (DDS), external-cavity diode laser (ECDL), arbitrary waveform generator (AWG), electro-optic phase modulator (EOM), acousto-optic modulator (AOM), device under test (DUT), photodiode detector (DET), dual-drive Mach–Zehnder modulator (DD-MZM).

Previously used methods often required Acousto-optic modulators, which are relatively expensive and have narrow bandwidths. They can also be difficult to fabricate in integrated photonics platforms.

Invention

Serrodyne modulation (i.e., using a sawtooth waveform to produce a linear phase chirp) is performed using an electro-optic phase modulator to provide the needed frequency shift. 

Potential Commercial Applications

This provides a pathway for comb generation and operation in a chip-scale package. This approach also reduces cost and complexity by reducing the number of components and fabrication steps.

Competitive Advantage

This lowers the associated cost by eliminating the need for a series of fiber optic splitters and individual modulators. Given the strong common-mode nature of the comb generation and the reduction of overall fiber length and number of components, the associated noise is expected to be lower.

Created July 11, 2024, Updated September 17, 2025
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