Repetition Rate Stabilization And Optical Axial Mode Linewidth Reduction Of A Chip-Scale Mll Using Regenerative Multitone Injection Locking

Keywords

Laser mode locking; microwave photonics; optoelectronic oscillators; semiconductor lasers; ultrafast optics

Abstract

A novel injection locking architecture is demonstrated to simultaneously improve the axial mode linewidth and stabilize the repetition rate of a monolithically integrated mode-locked laser. First, linewidth reduction is demonstrated via multitone injection locking. Then, the passive mode-locked laser is used as a source to make a coupled optoelectronic oscillator, and its RF spectral characteristics are investigated for different optical delays. A novel combination of these two techniques is established by creating a coupled optoelectronic oscillator via multitone injection locking, using an intracavity element as photodetector to generate the feedback signal to a Mach-Zehnder modulator. Using this combination of methods, the axial mode linewidth is reduced by over 6000× to ∼ 100 kHz and the RF linewidth is reduced by a factor of 70 at -30 dBc, resulting in a 3 dB RF linewidth of 400 Hz. The improvement in RF phase noise at 200 kHz offset is >40 dB. Finally, the system is referenced to a RF synthesizer using a variable voltage phase-shifter and a PID controller. Allan deviation measurements show a resolution limited stability in the repetition rate of 10-10 at 1 second following a 1 τ trend.

Publication Date

7-15-2018

Publication Title

Journal of Lightwave Technology

Volume

36

Issue

14

Number of Pages

2948-2954

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1109/JLT.2018.2822240

Socpus ID

85044752826 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85044752826

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