Command-shaping based on impulse response function for dynamic-mode control of internal and external cavities in...

Area of Science:

• Photonics and Laser Technology
• Optical Engineering
• Semiconductor Lasers

Background:

• External-cavity diode lasers (ECDLs) typically exhibit limited low-frequency tuning capabilities.
• Increased tuning frequency in ECDLs amplifies mechanical vibrations, degrading internal and external cavity mode-matching and reducing the mode-hop-free (MHF) tuning range.
• Achieving wide MHF tuning ranges at high frequencies is crucial for advanced laser applications.

Purpose of the Study:

• To present an active internal-cavity mode control method for dynamic mode-matching in ECDLs.
• To overcome the limitations of mechanical vibrations in achieving wide MHF tuning ranges with high-frequency tuning.
• To improve the performance of ECDLs for applications requiring rapid wavelength tuning.

Main Methods:

• Implementation of an impulse response function (IRF) shaper for active internal-cavity mode control.
• Dynamic mode-matching between the internal and external cavities of the ECDL.
• Experimental validation of the proposed method using an uncoated laser diode at a 785 nm central wavelength.

Main Results:

• Significant improvement in the MHF tuning range was observed with high-frequency tuning after introducing the IRF shaper.
• The active mode control method effectively mitigated the disruptive effects of mechanical vibrations.
• A maximum wavelength tuning rate of 7.56 THz/s was achieved.

Conclusions:

• The proposed active internal-cavity mode control method with an IRF shaper successfully enhances the MHF tuning range of ECDLs at high frequencies.
• This technique enables wider and faster wavelength tuning, overcoming inherent mechanical vibration limitations.
• The results demonstrate a promising approach for developing next-generation tunable laser systems.