High performance TM-pass polarizer using multimode Bragg grating waveguide.

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics

Background:

• Polarizers are crucial components in optical systems, enabling control over light polarization.
• Existing polarizers often face limitations in bandwidth, insertion loss, and polarization extinction ratio (PER).

Purpose of the Study:

• To propose and demonstrate a novel ultra-broadband TM-pass polarizer.
• To achieve high PER and low reflection across a wide operational bandwidth.

Main Methods:

• Utilizing a multimode Bragg grating waveguide (MBGW) structure combined with tapered waveguides.
• Optimizing the MBGW period to couple TE0 mode to backward TE2 mode for cladding leakage.
• Cascading multiple MBGW structures to expand operational bandwidth.

Main Results:

• Simulated insertion loss (IL) below 0.24 dB and PER above 39 dB across a 300 nm bandwidth (1400-1700 nm).
• Simulated reflected signal below -9.1 dB.
• Experimental results demonstrated IL below 0.56 dB and PER above 33 dB over a 160 nm bandwidth (1470-1630 nm).

Conclusions:

• The proposed MBGW-based polarizer achieves excellent performance metrics, including ultra-broadband operation.
• The device exhibits high PER and low IL, making it suitable for demanding optical communication applications.
• Further characterization across the full simulated bandwidth is recommended.