Thermorefractive noise reduction of photonic molecule frequency combs using an all-optical servo loop
Journal article, 2023
Phase and frequency noise originating from thermal fluctuations is commonly a limiting factor in integrated photonic cavities. To reduce this noise, one may drive a secondary “servo/cooling” laser into the blue side of a cavity resonance. Temperature fluctuations which shift the resonance will then change the amount of servo/cooling laser power absorbed by the device as the laser moves relatively out of or into the resonance, and thereby effectively compensate for the fluctuation. In this paper, we use a low noise laser to demonstrate this principle for the first time in a frequency comb generated from a normal dispersion photonic molecule micro-resonator. Significantly, this configuration can be used with the servo/cooling laser power above the usual nonlinearity threshold since resonances with normal dispersion are available. We report a 50 % reduction in frequency noise of the comb lines in the frequency range of 10 kHz to 1 MHz and investigate the effect of the secondary servo/cooling noise on the comb.
Author
Connor Skehan
Chalmers, Microtechnology and Nanoscience (MC2), Photonics
Anamika Nair Karunakaran
Technical University of Denmark (DTU)
NKT Photonics A/S
Poul Varming
NKT Photonics A/S
Òskar Bjarki Helgason
Chalmers, Microtechnology and Nanoscience (MC2), Photonics
Patrick B. Montague
NKT Photonics A/S
Jochen Schröder
Chalmers, Microtechnology and Nanoscience (MC2), Photonics
Minhao Pu
Technical University of Denmark (DTU)
K. Yvind
Technical University of Denmark (DTU)
Victor Torres Company
Chalmers, Microtechnology and Nanoscience (MC2), Photonics
Peter Andrekson
Chalmers, Microtechnology and Nanoscience (MC2), Photonics
Optics Express
1094-4087 (ISSN) 10944087 (eISSN)
Vol. 31 21 35208-35217Subject Categories
Telecommunications
Atom and Molecular Physics and Optics
Control Engineering
DOI
10.1364/OE.496895
PubMed
37859257