Polarization and spatial-mode behavior of short-wavelength VCSELs

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• 作者：Raja ; M. Yasin Akhtar ; Al-Dwayyan ; Abdullah ; Cao ; Yang ; Wang ; Charlie X.
• 关键词：VCSEL's characteristics ; Polarization behavior ; Spatial-modes
• 刊名：Optics and Laser Technology
• 出版年：2002
• 出版时间：March, 2002
• 年：2002
• 卷：34
• 期：2
• 页码：129-134
• 全文大小：198 K

文摘

We have investigated the packaging introduced feedback and resulting variations in the characteristics of Vertical-cavity surface-emitting lasers (VCSELs). An integrated test and characterization method was developed for both the packaged and bare dies as well as on-wafers chips. Using an ‘integrated test bench (ITB)’ for characterization, packaged and ‘un-packaged’ VCSELs from multiple sources were studied. ITB was used to monitor and measure simultaneously several beam-parameters under various bias conditions including both dc and high-speed pulsed pumping at room-temperature, or at higher-/lower-temperatures that are thermo-electrically controlled. Typical beam parameters included state of polarization (SOP), transverse (spatial) modes, wavelength spectra, and output power. A common observation was that majority of devices are affected by the presence of optical windows capping the package. A shift in longitudinal mode was noticeable in packaged versus ‘un-packaged’ (window-removed) devices. But, SOP and transverse modes in various devices are affected severely and in an unpredictable fashion.