Vertical-cavity Surface-emitting Laser Sources Research Articles

Dynamics of dual-polarization VCSEL-based optical frequency combs under optical injection locking.

The present experimental work studies the dynamics of dual-polarization optical frequency combs (OFCs) based on gain switching (GS) vertical-cavity surface-emitting laser (VCSEL) diodes under optical injection locking (OIL). This study presents two main results. First, we have obtained an overall comb formed by two orthogonally polarized sub-combs with comparable span and power. The overall comb shows enhanced optical span and flatness and high coherence between its modes. The second result is that we have been able to control the polarization state of the overall comb by tuning the polarization state of the injected light by locking the same single teeth of the comb. This produces an overall comb with single polarization that is parallel or orthogonal. These are novel findings that provide for the development of efficient and compact OFCs based on GS VCSEL sources with versatile polarization dynamics.

In vivo cross-sectional imaging of the phonating larynx using long-range Doppler optical coherence tomography.

Diagnosis and treatment of vocal fold lesions has been a long-evolving science for the otolaryngologist. Contemporary practice requires biopsy of a glottal lesion in the operating room under general anesthesia for diagnosis. Current in-office technology is limited to visualizing the surface of the vocal folds with fiber-optic or rigid endoscopy and using stroboscopic or high-speed video to infer information about submucosal processes. Previous efforts using optical coherence tomography (OCT) have been limited by small working distances and imaging ranges. Here we report the first full field, high-speed, and long-range OCT images of awake patients’ vocal folds as well as cross-sectional video and Doppler analysis of their vocal fold motions during phonation. These vertical-cavity surface-emitting laser source (VCSEL) OCT images offer depth resolved, high-resolution, high-speed, and panoramic images of both the true and false vocal folds. This technology has the potential to revolutionize in-office imaging of the larynx.

Single-exposure two-dimensional superresolution in digital holography using a vertical cavity surface-emitting laser source array

We present a new implementation capable of producing two-dimensional (2D) superresolution (SR) imaging in a single exposure by aperture synthesis in digital lensless Fourier holography when using angular multiplexing provided by a vertical cavity surface-emitting laser source array. The system performs the recording in a single CCD snapshot of a multiplexed hologram coming from the incoherent addition of multiple subholograms, where each contains information about a different 2D spatial frequency band of the object's spectrum. Thus, a set of nonoverlapping bandpass images of the input object can be recovered by Fourier transformation (FT) of the multiplexed hologram. The SR is obtained by coherent addition of the information contained in each bandpass image while generating an enlarged synthetic aperture. Experimental results demonstrate improvement in resolution and image quality.

Statistical Study of Graded-Index Perfluorinated Plastic Optical Fiber

Plastic fiber-based optical links have been proposed for a wide variety of high-speed short reach applications. Graded-index (GI) multimode plastic optical fiber (POF) that supports 10 Gb/s over 50 m is commercially available and 40 Gb/s over 100 m has been demonstrated. However, unlike single-mode fiber and like silica multimode fiber (MMF), GI POF exhibits a range of performance that depends on launch condition and the accuracy of the index profile. Here, we report on the first statistical study of a large set of GI POF. We examine >; 40 samples of 62.5 μm core POF with four different cabling types that represent current-generation commercially available POF. We assess performance in terms of the 10 GbE requirements and quantify loss, chromatic dispersion, differential modal delay, effective modal bandwidth (EMB), and eye closure penalty. We find that nearly all of the measured 100 m fibers support the strict 10 GbE vertical-cavity surface emitting laser source EMB requirement, and that many fibers can support >; 40 Gb/s over 100 m. We thus demonstrate that GI POF can reliably support 10 Gb/s and larger bit rates to distances of 100 m.

15-gb/s bit-interleaved optical backplane bus using volume photopolymer holograms

A 15-Gb/s bit-interleaved optical backplane bus interconnection is experimentally demonstrated in a three-board system based on optical backplane using volume photopolymer holograms. During upstream data transferring, bit pulses from each daughter board are superposed to form an interleaved sequence while for downstream data transferring, the data broadcast from the central board are time-division demultiplexed locally at each daughter board, and only the destined bits are stored respectively. In this way, slow electronic chips can be coordinated to generate a high aggregated bandwidth to relieve wiring congestion. Both nonreturn-to-zero and return-to-zero signaling modes based on vertical-cavity surface-emitting laser sources and pulse lasers are independently employed to implement 2.5- and 15-Gb/s operations. This optical bus architecture also provides a secure and reliable data storage method at 850 nm with a bit-error rate better than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12 </sup>