Using ferrule-top opto-mechanical probes as a new tool in VCSEL reliability experiments

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Vertical cavity surface emitting lasers (VCSELs) are crucial in high-end applications where device lifetime is critical.
• Monitoring VCSELs for degradation is essential for ensuring reliability and performance.
• Changes in transverse mode patterns can indicate early stages of device failure.

Purpose of the Study:

• To develop an advanced microscopy technique for analyzing VCSEL transverse mode patterns.
• To achieve high spatial resolution for detecting subtle changes in optical output.
• To enable earlier detection of VCSEL degradation compared to conventional methods.

Main Methods:

• Development of a ferrule-top combined atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM) probe.
• Analysis of the transverse mode pattern of 850 nm radiation emitted by VCSELs.
• Utilizing a spatial resolution of less than 200 nm for detailed analysis.

Main Results:

• The developed AFM-SNOM probe successfully analyzed VCSEL transverse mode patterns with high spatial resolution.
• Small local changes in optical output were detected during accelerated lifetime testing.
• These changes were observable before any signs of device degradation were apparent using conventional methods.

Conclusions:

• The combined AFM-SNOM probe offers a sensitive method for early detection of VCSEL degradation.
• This technique enhances the speed and detail of failure mode analysis for VCSEL devices.
• Improved monitoring capabilities can lead to increased reliability and longevity of VCSELs in critical applications.