Optofluidic tunable mode-locked fiber laser using a long-period grating integrated microfluidic chip

Area of Science:

• Photonics
• Optofluidics
• Fiber Lasers

Background:

• Mode-locked fiber lasers are crucial for various applications, but achieving tunable wavelengths often requires complex setups.
• Long-period gratings (LPGs) offer spectral filtering capabilities but typically lack dynamic tunability.
• Optofluidic integration presents a novel approach for dynamic control of optical properties.

Purpose of the Study:

• To develop an optofluidic tunable mode-locked fiber laser.
• To demonstrate continuous wavelength tuning of a fiber laser using a microfluidic-controlled LPG.
• To investigate the generation and characteristics of bound solitons in the tunable laser system.

Main Methods:

• Integration of a microfluidic chip with a long-period grating (LPG) within a fiber laser cavity.
• Utilizing the microfluidic chip to precisely tune the refractive index of the fluid, thereby altering the LPG's spectrum.
• Characterization of the mode-locked laser output, including pulse duration, repetition rate, and soliton properties.

Main Results:

• The optofluidic tunable fiber laser achieved continuous central wavelength tuning.
• Stable mode-locking was maintained throughout the tuning process.
• Mode-locked pulses with a 0.9 ps duration and 12.14 MHz repetition rate were measured.
• Experimental demonstration of bound solitons with adjustable separations was achieved.

Conclusions:

• The proposed optofluidic tunable filter based on a microfluidic-integrated LPG is effective for controlling fiber laser wavelengths.
• This approach offers a stable and continuously tunable mode-locked fiber laser.
• The demonstrated bound soliton generation highlights the system's versatility for advanced ultrashort pulse applications.