Category: Broadband Sources

By characterizing the light emission from a multi-section reconfigurable quantum dot (QD) edge-emitting LED, measured gain and unamplified spontaneous emission characteristics pertaining to the underlying gain material can be determined. This data can then be inserted into a set of equations capable of reproducing the spectral emission when the device is configured as a superluminescent diode (SLD). The accuracy of this model is validated for a highly p-doped QD multi-section LED. Excellent agreement is obtained between the model and the actual measured light output from the QD SLD.

The supercontinum generation has been achieved mainly by two different approaches, namely, with femtosecond intense pulses or using a continuous wave laser or larger pulses centered on the anomalous dispersion region. In order to improve temporal coherence, it has been suggested the introduction of a pulse seed or the propagation of both a large pulse pump and a small weaker continuous wave to control the soliton fission. Here we propose supercontinuum generation using a hybrid input, we pump with a continuous laser and copropagate a picosecond signal. We compare the bandwidth of the supercontinuum using only the continuous pump or ...

Glass-clad TiAlO3 crystal fibers were grown using the codrawing laser-heated pedestal growth method. Both single-clad and double-clad structures were attempted. Using a 446-nm laser diode as the pump, 2.45 mW of collimated broadband emission was generated with a 3-dB bandwidth of 180 nm. As much as 7.7 mW of output power with a 3-dB bandwidth of 182 nm was generated using a 532-nm solid-state pump laser. The broadband light source is advantageous to use in optical coherence tomography with an axial resolution of 1.5 um in air and a low image pixel crosstalk.

The optical loss in the bent region is one of the key features for bent-waveguide superluminescent diodes which affects the device performance greatly under some conditions. In our work, this bend loss is investigated with different waveguide structural parameters such as the ridge width, etching depth and curvature radius. It is found that the bend loss is sensitive to the etching depth of the ridge. Significant loss will occur in a shallow and excessively wide or narrow ridge waveguide, and the waveguide with a small curvature radius can also enhance the loss. Effects of the loss on the device properties ...

An unconventional photonic crystal fiber (PCF) is designed in order to obtain supercontinuum (SC) generation. The distance of the air hole rings is not constant, but it follows the Thue-Morse (ThMo) aperiodic sequence. The spectral broadening of high power femtosecond (fs) input pulses in anomalous dispersion regime is investigated by means of a homemade computer code, based on the generalized nonlinear Schrödinger equation (GNLSE) and implemented via the symmetrized split-step Fourier method (S-SSF). A lot of ThMo PCF transversal sections are simulated, and the one providing the flattest and the widest spectrum is identified and further refined by varying the ...

This paper discusses about the tailoring supercontinuum (SC) generation based on a highly nonlinear germanium (Ge) doped photonic crystal fiber (HNL-GePCF) with all normal group velocity dispersion (GVD). Using finite element method (FEM) with a circular perfectly matched boundary layer (PML), it is shown through simulations that how simply the center wavelength can be shifted from one center point to another after optimizing at a particular wavelength using the proposed HNL-GePCF. Moreover, SC spectra at 1.06, 1.31 and have been generated using picosecond optical pulses produced from relatively less expensive laser sources.

We have been investigating ultrahigh resolution optical coherence tomography (UHR-OCT) imaging of lung tissues using fiber super continuum sources. The high power, low-noise, Gaussian shaped supercontinuum generated with ultrashort pulses and optical fibers at several wavelengths were used as the broadband light sources for UHR-OCT. For the 800 nm wavelength region, the axial resolution was 3.0 um in air and 2.0 um in tissue. Since the lung consists of tiny alveoli which are separated by thin wall, the UHR-OCT is supposed to be effective for lung imaging. The clear images of alveoli of rat were observed with and ...

Optical coherence tomography (OCT) is a non invasive optical imaging technology for micron-scale cross-sectional imaging of biological tissue and materials. We have been investigating ultrahigh resolution optical coherence tomography (UHR-OCT) using fiber based supercontinuum sources. Although ultrahigh longitudinal resolution was achieved in several center wavelength regions, its low penetration depth is a serious limitation for other applications. To realize ultrahigh resolution and deep penetration depth simultaneously, it is necessary to choose the proper wavelength to maximize the light penetration and enhance the image contrast at deeper depths. Recently, we have demonstrated the wavelength dependence of penetration depth and imaging contrast ...

Low thermal resistance of high power superluminescent diodes (SLEDs) by using active multi-mode interferometer (active-MMI) is presented in this paper. The active layer temperature evaluation demonstrates that the power saturation mechanism in active-MMI SLED is heat for the first time. Low thermal resistance of 4.83 K/W in active-MMI SLEDs leads to a high power of 115 mW. Moreover, the effect of the active area size on the output power is demonstrated both experimentally and theoretically. Good agreement between the theoretical and experimental results indicates that active-MMI configuration is a new design in support of efficient heat dissipation and ...

Exalos Press Release - EXALOS AG is introducing a new series of high-performance Broadband Light Sources (spectrally combined Superluminescence Light Emitting Diodes) with ultra-broad optical spectrum centered around 1020 nm, 1040 m and 1075 nm. With typical 3-dB bandwidths well above 100 nm and high optical output powers of more than 15 mW the EBS4C32, EBS8C33 and EBS4C34 are perfectly suited for Optical Coherence Tomography (OCT), biomedical imaging, component testing or spectroscopy applications requiring a light source in the near IR. These Broadband Light Sources are offered as turn-key R&D benchtop systems and will be presented at our booth 8322 ...

Passively mode-locked fiber lasers are stable and practical ultrashort pulse sources. We have been investigating the highly functional wideband ultrashort pulse fiber laser sources using ultrafast fiber nonlinear effects. These novel light sources are useful for multi-photon memory, multi-photon miscropscopy, spectroscopy, ultrahigh resolution optical coherence tomography, etc. In this talk, the development and applications of the highly functional ultrashort pulse fiber lasers are explained. Recently, single wall carbon nanotube (SWNT) absorbs a lot of attention as the new nonlinear optical devices. It shows the saturable absorption properties and the recovery time is ~1 ps. The environmental stability is one of ...

The present invention provides an amplified spontaneous emission fiber optic source having high optical power (>20 mW) and a spectral broadband emission (>70 nm) centered near a wavelength of 1060 nm. In an embodiment of the invention, the fiber source comprises a combination of Yb-doped and Nd-doped silica fibers in a dual-pumping configuration. The Yb-doped optical fiber has a peak absorption coefficient of 350 dB/nm at 977 nm band, and the Nd-doped fiber used has a dopant concentration of 500 ppm-wt in a glass host of aluminum-germano-phospho-silicate. A combination of these two doped-fibers along with optical spectral filtering provides ...

Based on InAs/GaAs quantum dots [QDs], a high-power and broadband superluminescent diode [SLD] is achieved by monolithically integrating a conventional SLD with a semiconductor optical amplifier. The two-section QD-SLD device exhibits a high output power above 500 mW with a broad emission spectrum of 86 nm. By properly controlling the current injection in the two sections of the QD-SLD device, the output power of the SLD can be tuned over a wide range from 200 to 500 mW while preserving a broad emission spectrum based on the balance between the ground state emission and the first excited state emission ...

We generate a flat, polarized and single mode Supercontinuum (SC) spanning at least from 600nm to 1700nm in a 20m length of highly refringent photonic crystal fibers (PCFs) pumped by a 1064 nm nanosecond microchip laser. The spectrum and polarization properties of the SC are investigated experimentally. The experimental results and the analysis provide useful information that helps to optimize and tune the properties of the polarized SC sources.

The dispersion characteristics of Arsenic Trisulfide As2S3 chalcogenide glass were analyzed and a kind of As2S3 microstructured optical fiber was designed to shift the zero dispersion wavelength from longer than 4 μm to around 2 μm. The supercontinuum generation in the designed fiber with selected pump wavelengths and pulse durations were simulated through numerically solving the Generalized Nonlinear Schrdinger Equation. The results reveal that the broadest supercontinuum covering 1.1 μm to 5.5 μm can be obtained with pump laser with duration 150 fs centered at 2.0 μm which is slightly longer than the first zero dispersion wavelength ...