Tunable external cavity laser employing uncooled superluminescent diode

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Superluminescent diodes (SLEDs) are crucial for optical communication systems.
• Tunable lasers are essential for flexible wavelength division multiplexing passive optical network (WDM-PON) systems.
• Existing tunable laser solutions can be complex and expensive.

Purpose of the Study:

• To develop a cost-effective tunable external cavity laser (T-ECL) for WDM-PON systems.
• To demonstrate wavelength tunability using a polymeric waveguide Bragg reflector.
• To evaluate the performance of the T-ECL for high-speed optical data transmission.

Main Methods:

• Fabrication of a T-ECL integrating a SLED with a polymeric waveguide Bragg reflector.
• Thermo-optic tuning of the polymer waveguide's refractive index to achieve wavelength shifting.
• Characterization of output power, slope efficiency, and transmission performance at 1.25 Gbit/s.

Main Results:

• The T-ECL successfully tuned across 16 channels with 100 GHz spacing.
• Low input power (70 mW) was sufficient for wavelength tuning.
• Maximum output power of 8.83 mW and slope efficiency of 0.107 W/A were achieved at 20°C.
• Successful 1.25 Gbit/s data transmission over 20 km was demonstrated.

Conclusions:

• The developed T-ECL provides a cost-effective and tunable light source for WDM-PON.
• The thermo-optic tuning mechanism in polymer waveguides is effective for channel selection.
• The T-ECL shows promise for practical implementation in next-generation optical communication networks.