Tali Septon


Viterbi Faculty of Electrical Engineering, Technion

Stable Laser Reference System for Optical Metrology and Spectral Characterization of Narrow Linewidth QD-DFB Lasers

Linewidth is a measure of the frequency stability of any kind of oscillator, and it is a defining characteristic of coherent lasers. Narrow linewidth laser technology, particularly in the field of infrared lasers, has progressed to the point where highly stable sources are commercially available with linewidths on the order of 1-100 kHz. In order to achieve a higher level of stability, the laser must be augmented by an external frequency stabilization system. An optical frequency comb is a laser source whose spectrum consists of a series of discrete, equally spaced frequency lines. By Locking one of the comb lines to a narrow linewidth laser serving as an optical reference, the phase noise of the comb is reduced significantly and can be used for precision frequency measurements. This form of a stabilized comb is also the most basic version of an optical clock. In this talk, I will introduce the design and characterization of an experimental setup for an ultra-narrow linewidth laser. Using the Pound-Drever-Hall technique, the system significantly reduces the linewidth of an input laser with an un-stabilized linewidth of 5 kHz. It uses a high-finesse Fabry-Perot cavity, which is thermally isolated, as a frequency reference to measure the time-varying frequency of the input laser. Experiments have proven the Pound-Drever-Hall system to be highly stable and capable of operating continuously for days. The system was used to characterize narrow linewidth Quantum Dot DFB lasers. Record values of 20 kHz at 200 C and less that 80 kHz at 800 C were demonstrated. The same stabilized comb is also used for a future Rubidium based optical atomic clock, and experiments in broadcasting high precision optical clock signals over fiber to long distance *   M.Sc. research under the supervision of Prof. Gadi Eisenstein.

Date: Mon 18 Feb 2019

Start Time: 14:30

End Time: 15:30

1061 | Electrical Eng. Building