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Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
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Threshold behavior of optical frequency comb self-generation in an InAs/InGaAs quantum dot laser
Optics Letters
|July 16, 2019
Summary
Injection current control significantly narrows the radio-frequency beat note line width of quantum dot lasers. This method achieves self-locking of longitudinal modes, reducing line width to 20 kHz for improved laser performance.
Area of Science:
- Semiconductor physics
- Optoelectronics
- Quantum dot lasers
Background:
- Fabry-Perot semiconductor lasers are crucial for optical communications.
- Quantum dot (QD) lasers offer unique properties but often suffer from broad linewidths.
- Controlling longitudinal mode behavior is key to enhancing laser stability and performance.
Purpose of the Study:
- To investigate the effect of injection current control on the radio-frequency (RF) beat note line width and relative intensity noise (RIN) of a monolithic InAs/InGaAs quantum dot semiconductor laser.
- To explore the phenomenon of longitudinal mode self-locking in QD lasers induced by internal non-linear effects.
- To demonstrate a method for significantly reducing the RF beat note line width and RIN.
Main Methods:
- Utilized a 1 mm long edge-emitting monolithic Fabry-Perot InAs/InGaAs quantum dot semiconductor laser operating at 1250 nm from the ground state.
- Systematically varied the injection current above the lasing threshold.
- Measured the RF beat note line width and integrated RIN.
- Performed simulations to validate experimental observations.
Main Results:
- Observed unlocked multi-mode behavior at lower injection currents.
- Demonstrated self-locking of longitudinal modes at a specific injection current above threshold due to internal non-linear effects.
- Achieved a significant reduction in RF beat note line width to 20 kHz (-3 dB), a drastic improvement from tens of megahertz.
- Reported a substantial reduction in integrated relative intensity noise.
Conclusions:
- Injection current control is an effective method for enhancing the spectral purity of quantum dot lasers.
- Self-locking of longitudinal modes, driven by non-linear effects, is achievable and beneficial for reducing line width.
- The demonstrated technique offers a pathway towards developing more stable and higher-performance quantum dot lasers for various applications.
