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A sub-wavelength grating has been added to an optically pumped MEMS tunable VCSEL structure to control polarization. This "P_VCSEL" is a thermocompression-bonded sandwich of a 1/2-VCSEL with gain and semiconductor DBR attached to a silicon MEMS mirror on an electrostatically actuated membrane for wavelength control. The sub-wavelength pitch grating is etched into the surface of the 1/2-VCSEL. Optical layer stack simulations have accurately predicted the tuning behavior of the P_VCSELs but not the polarization behavior. The polarization selection does not occur through threshold gain asymmetries as originally believed, but rather through polarization-dependent loss in the grating. We believe the rough sidewalls of the grating teeth are responsible for the polarization-dependent loss. While the selected-against polarization loss is very high, the selected-for polarization loss is still higher than desirable. This reduces power output, especially at short wavelength. However, 91 nm tuning in the 1050 nm band was achieved, suitable for application in optical coherence tomography.
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http://dx.doi.org/10.1364/OE.560278 | DOI Listing |
Adv Sci (Weinh)
August 2025
The Greater Bay Area University Joint Laboratory of Micro- and Nanofabrication, Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
Additive manufacturing technology has the potential to provide great versatility in the design and fabrication of sensing devices. This prerequisite necessitates further technological improvement in precision and material diversity. Here, a universal meniscus-guided 3D printing method is reported that can fabricate freestanding metal oxide semiconducting nanowires with programmed compositions and compatible substrate options at the single-entity level.
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August 2025
Department of Electrical and Computer Engineering, National University of Singapore, Singapore.
The ability to shape light spectra dynamically and arbitrarily would revolutionize many photonic systems by offering unparalleled spectral efficiency and network flexibility. However, most existing optical components have rigid spectral functionalities with limited tunability, hindering compact and fast optical spectral shaping. We introduce a pixelated nano-opto-electro-mechanical (NOEM) grating that exploits electromechanically induced symmetry breaking for precise, pixel-level control of grating coupling strength, yielding a miniaturized (~0.
View Article and Find Full Text PDFA sub-wavelength grating has been added to an optically pumped MEMS tunable VCSEL structure to control polarization. This "P_VCSEL" is a thermocompression-bonded sandwich of a 1/2-VCSEL with gain and semiconductor DBR attached to a silicon MEMS mirror on an electrostatically actuated membrane for wavelength control. The sub-wavelength pitch grating is etched into the surface of the 1/2-VCSEL.
View Article and Find Full Text PDFOpt Express
February 2025
A turnkey phase-sensitive swept-source optical coherence tomography (OCT) system requires stabilization of both the swept source and main signal interferometer. We have provided stable clocking and triggering of a 1050 nm swept micro-electromechanical system (MEMS) vertical cavity surface emitting laser (VCSEL) by mounting a solid clock etalon and volume Bragg grating optical trigger inside a temperature-stabilized butterfly package. A photonic integrated circuit (PIC) provides a phase-stable main interferometer near the sample.
View Article and Find Full Text PDFThis work presents laser absorption-based pressure measurements in a simulated post-detonation environment to experimentally study the dynamic range, accuracy, and sensitivity of optically measured gas pressures in dynamic flow fields. Experiments were conducted in Sandia National Laboratories' Multiphase and High-Temperature Shock Tubes using a micro-electromechanical system, tunable vertical cavity surface emitting laser (MEMS-VCSEL) scanning 7350-7900 at 100 kHz to measure water vapor absorption spectra at pressures ranging from 0.25 to 67 atm and temperatures from 293 to 2300 K.
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