PhD10: Muhammad Asim Bashir

Host: University of Lübeck

Secondments: Optores GmbH, and RECENDT GmbH (Research Center for Materials Characterization and Non-Destructive Testing)

PhD project: Super broadband FDML Laser for Optical Coherence Tomography

In swept source optical coherence tomography (SS-OCT), the axial resolution depends on the spectral bandwidth of the used light source. Typical bandwidths of a single Fourier domain mode-locked (FDML) laser of >110 nm yield resolutions of ∼8 µm. Since the sweep range of a single laser is limited, a combination of several/two individual FDML lasers is necessary to enhance the axial resolution up to ∼2 µm. So, to achieve the project goal, the first Fourier domain mode-locked (FDML) laser centered around 1190nm with a 2x410kHz sweep repetition rate and a sweeping range of 100 nm at 3 mW output power is successfully built. The FDML laser is constructed using a quantum dot-semiconductor optical amplifier, which is well-known for its ultrafast gain recovery time and extremely small linewidth enhancement factor. A tuneable Fabry Perot filter, an isolator, a long fiber cavity, and a chirped fiber Bragg grating are used to compensate for the -10.5ps/nm dispersion. The experiment for the second FDML is going on, which is centered at 1060nm, and it will sweep over 200 nm. After the completion of the second laser, the synchronization between the two lasers is planned, and the desired axial resolution will be achieved. 

Completed workshops, Seminars, and Conferences:

  • 1st NETLAS Event, International Day of light conference – Tampere University, Finland, OCT & photonics, Online Poster presentation “1190 nm FDML for OCT 20-21/05/2021      
  • 2nd NETLAS Event, Winter School – DTU Copenhagen, Denmark, Title oral presentation  “1190 nm FDML for OCT“,  01-04/03/2022   
  • 3rd NETLAS Event, Autumn School – TUD Darmstadt, Germany, Title oral presentation “Problems and Strategies for 1190 FDML“, 04-07/10/2022
  • Photonics West – San Francisco, Title oral presentation “1190 nm Fourier domain mode-locked (FDML) laser for optical coherence tomography (OCT)30/01/2023
  • Siegman School on Lasers in Dublin, Ireland, Poster presentation “Novel 1190 nm FDML Laser23-06-2023
  • 4th NETLAS Event, NETLAS Conference in conjunction with Markus Pessa International Summer School “New Frontiers in Optical Technologies”, Title oral presentation “1190 nm FDML Laser with tandem gain configurationAugust 7 – 11, 2023, Tampere, Finland

Publications:

  • M. Klufts, S. Lotz, M. Bashir, S. Karpf and R. Huber, “Ultra-high-accuracy chromatic dispersion measurement in optical fibers”, Optical Components and Materials XIX, no. 11997, pp. 146 – 152, SPIE, 2022, https://doi.org/10.1117/12.2608773
  • M. Klufts, S. Lotz, M. A. Bashir, T. Pfeiffer, A. Mlynek, W. Wieser, A. Chamorovskiy, V. Shidlovski, R. Huber, “850 nm FDML: performance and challenges,” Proc. SPIE 12367, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXVII, 1236705 (8 March 2023); https://doi.org/10.1117/12.2649646
  • M. A. Bashir, S. Lotz, M. Klufts, I. Krestnikov, C. Jirauschek, R. Huber, “1190 nm Fourier domain mode locked (FDML) laser for optical coherence tomography (OCT),” Proc. SPIE 12367, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXVII, 1236707 (8 March 2023); https://doi.org/10.1117/12.2652884

Previous education:

Master’s in Optical Engineering, Sejong University, Seoul, South Korea (2019-2021)

Master Thesis: Development of unidirectional and bidirectional broadband wavelength swept lasers for Optical Coherence Tomography

Bachelor’s in Electrical Engineering with specialization in Electronics Engineering, Bahria University Islamabad, Pakistan (2013-2017)