Long-range tunable diode laser.

Area of Science:

• Optics and Photonics
• Laser Physics
• Semiconductor Devices

Background:

• Single-mode diode lasers are crucial for various applications.
• Achieving wide, continuous tuning ranges in diode lasers remains a challenge.
• Existing tuning mechanisms often require complex setups or external cavities.

Purpose of the Study:

• To develop a novel and simple tuning mechanism for single-mode, pseudo-external-cavity diode lasers.
• To experimentally validate the predicted continuous tuning range.
• To demonstrate enhanced tunability without external cavity locking.

Main Methods:

• A pseudo-external-cavity diode laser was designed using a commercial laser diode chip.
• A diffraction grating was employed for optical feedback.
• A turning wedge was integrated within the laser cavity as the primary tuning element.

Main Results:

• Model calculations predicted a continuous tuning range of up to 300 GHz.
• Experimental results demonstrated a continuous tuning range of approximately 120 GHz at constant current and temperature.
• The achieved tuning range is several times greater than previously reported values for similar systems.
• The total tuning range can extend up to 20 nm, depending on the laser diode type.

Conclusions:

• The developed tuning mechanism provides a simple and effective method for achieving wide continuous tuning in diode lasers.
• The pseudo-external-cavity design with an internal turning wedge offers significant advantages in laser tunability.
• This technology has the potential to advance applications requiring precise and broad wavelength selection in diode lasers.