A novel concavely apodized DFB semiconductor laser using common holographic exposure

Area of Science:

• Optoelectronics
• Semiconductor Lasers
• Nanophotonics

Background:

• Distributed feedback (DFB) semiconductor lasers are crucial for optical communications.
• True concavely apodized (CA) gratings offer improved performance but are complex and costly to fabricate.
• A need exists for cost-effective methods to achieve CA grating profiles in DFB lasers.

Purpose of the Study:

• To theoretically analyze and experimentally demonstrate a novel, cost-effective method for realizing CA grating profiles in DFB semiconductor lasers.
• To investigate the performance of semiconductor lasers fabricated using this new technique.

Main Methods:

• Equivalent realization of CA grating profile by varying duty cycle of sampling structure along the cavity.
• Insertion of an equivalent phase shift in the middle of the cavity.
• Utilizing a uniform seed grating requiring common holographic exposure and photolithography.
• Theoretical analysis and experimental demonstration.

Main Results:

• Successful theoretical analysis and experimental demonstration of the novel CA DFB semiconductor laser.
• The fabricated laser exhibits good single longitudinal mode operation.
• The fabrication process is simplified and cost-effective compared to true CA gratings.

Conclusions:

• The proposed method provides an efficient and economical approach to achieve CA grating profiles in DFB semiconductor lasers.
• This technique enables the production of high-performance DFB lasers with reduced fabrication complexity and cost.
• The demonstrated laser shows promising results for applications requiring stable single longitudinal mode operation.