Method for measuring the phase error distribution of a wideband arrayed waveguide grating in the frequency domain

Area of Science:

• Photonics and Optical Engineering
• Waveguide Optics
• Interferometry

Background:

• Arrayed waveguide gratings (AWGs) are crucial components in wavelength division multiplexing (WDM) systems.
• Measuring phase error distribution is essential for optimizing AWG performance.
• Wide free spectral ranges (FSRs) pose challenges for conventional measurement techniques.

Purpose of the Study:

• To develop and validate a novel method for measuring the phase error distribution of AWGs with wide FSRs.
• To overcome the limitation of single tunable laser sources in characterizing AWGs.
• To enable accurate phase error assessment in the frequency domain.

Main Methods:

• Utilizing two laser sources with different tuning ranges to sweep frequencies around successive transmission peaks.
• Applying the method to an arrayed waveguide grating (AWG) with a 160 GHz channel spacing and 11 THz FSR.
• Analyzing the AWG transmission spectrum in the frequency domain.

Main Results:

• The developed method successfully measured the phase error distribution.
• Experimental validation on a 160 GHz spaced AWG with an 11 THz FSR was performed.
• Phase error variations were found to be minimal, within +/-0.02 radians around central waveguides.

Conclusions:

• The proposed frequency domain method is effective for characterizing AWGs with wide FSRs.
• The technique provides accurate phase error measurements, crucial for device performance.
• The minimal phase error variations indicate high-quality fabrication and performance of the tested AWG.