Born in Berlin,[1][2] Schwefel spent his undergraduate years from 1994 till 1998 studying physics and maths at Brandenburg University of Technology (BTU) Cottbus in Germany.

[5] He organised strikes and demonstrations in response to savings plans proposed by Science Minister Steffen Reiche in a draft of the Brandenburg Higher Education Act that granted unlimited rights to close and merge universities.

[13][14][15] Schwefel moved to New Zealand in September 2015 where he has reestablished his research programme as a senior lecturer in the Department of Physics at the University of Otago[13][10] and a principal investigator in the Dodd-Walls Centre for Photonic and Quantum Technologies.

He specialises in whispering gallery mode resonators (WGMRs), small disks of dielectric materials which are used to confine, store and therefore intensify light to facilitate nonlinear interactions.

[17] These devices are based on the whispering gallery wave phenomenon, where laser light bounces around the inner surface of a dielectric disc, confined by total internal reflection.

[18] Schwefel began research on WGMRs at the Max Planck Institute and has further developed fabrication techniques to achieve high quality factors,[19][20][14] which means that large amounts of laser light can be confined and stored within the resonator with very little leakage.

[17] Schwefel and his team have used WGMRs made of second order nonlinear crystals, such as lithium niobate, to generate optical frequency combs of record efficiency.

[22] These devices show potential to significantly improve the efficiency of the internet by reducing the power required to encode data and the information-carrying capacity of optical fibres.

Schwefel and his team are collaborating with New Zealand-based optical technology company Coherent Solutions to develop applications and are also investigating the use of their frequency combs for high-precision spectroscopy.

Schwefel and his team have found that placing a WGMR as a passive filtering element within the loop of a fibre laser reduces the line width to sub-kHz levels, which improves the stability of the system.