Micrometer-scale all-optical wavelength converter on silicon

We demonstrate a highly integrated micrometer-scale low-power wavelength converter based on the free-carrier dispersion effect in silicon. The conversion is achieved through all-optical modulation of a silicon ring resonator by use of modulated cw control light. The ring resonator has a radius of 5 microm and a Q of approximately 10,000. Both inverted and noninverted modulation are achieved at a bit rate of 0.9 Gbits/s with a control power of 4.5 mW. The scaling of the required control power for operation with respect to the characteristics of the ring resonator is established.     

Continuous-wave wavelength conversion for high-power applications using an external cavity diamond Raman laser

We demonstrate continuous-wave (cw) operation of a diamond Raman laser at 1240 nm in an external cavity configuration. The output power increased linearly with pump power with a 49.7% slope efficiency and reached 10.1 W at the maximum available pump power of 31 W. The combination of resonator design with diamond provides a novel approach to power-scalable cw wavelength and beam conversion.     

Continuous-wave laser at 440 nm based on frequency-doubled diode-pumped Nd:GdVO(4) crystal

We present for the first time, to the best of our knowledge, a frequency-doubled Nd:GdVO(4) laser operating in a cw on the pure three-level laser line at 880 nm. We obtained 300 mW at 440 nm for 23 W of incident pump power at 808 nm. Moreover, with a 25% output coupler we obtained a cw power of 1.9 W at the fundamental wavelength at 880 nm.     

High-brightness 2.4-W continuous-wave Nd:GdVO4 laser at 670 nm

We report on a diode-pumped 1.3-microm Nd:GdVO4 cw laser, intracavity doubled for highly efficient generation of red light. We obtained as much as 2.4 W of power at 670 nm (corresponding to 26% optical-to-optical efficiency) in a nearly TEM00 mode and with small amplitude noise. To the best of our knowledge, these results represent the highest performance at this wavelength for cw solid-state lasers.     

Micro-optical 3-dB mode converters

We present a detailed design of a 3-dB TE₀-TE₁ micro-optical mode converter using a chirped grating to phase-match the two propagation modes in an optical waveguide. Devices were fabricated in titanium in-diffused lithium niobate by ion-beam etching the tapered grating pattern into the waveguide surface. The power transfer between the two coupled modes was observed experimentally by varying the angle between the light beam and the normal grating wave-vector. Insertion loss of the TE₀-TE₁ mode converter due to spurious scattering was estimated at 1.5 dB.     

Rapidly tunable continuous-wave optical parametric oscillator pumped by a fiber laser

We report on rapid, all-electronically controlled wavelength tuning of a continuous-wave (cw) optical parametric oscillator (OPO) pumped by an ytterbium fiber laser. The OPO is singly resonant for the signal wave and consists of a 40-mm-long periodically poled lithium niobate crystal in a four-mirror ring cavity. By tuning of the fiber-laser wavelength over 33 nm through an intracavity acousto-optic tunable filter, the OPO idler wavelength is tuned from 3160 to 3500 nm in 330 micros, corresponding to an idler frequency-tuning speed of 28 THz/ms. At a fiber-laser power of 6.6 W at 1074 nm, the singly resonant OPO generates 1.13-W cw idler radiation at 3200 nm.     

Stable 10 W Er:ZBLAN fiber laser operating at 2.71-2.88 μm

We have developed a diode-pumped tunable 3 μm fiber laser with a cw output power of the order of 10 W with the use of an erbium-doped ZBLAN fiber. A tunability range of 110 nm (2770 to 2880 nm) with an output power between 8 and 11 W was demonstrated. As the pump power was increased, the center of the wavelength range was shifted toward longer wavelengths, but the width of the wavelength range was largely unaffected. The total tunability range for various pump power levels was 170 nm (2710 to 2880 nm). To our knowledge, this is the highest performance (output power and tunability) obtained from a tunable 3 μm fiber laser.     

Continuous‐wave optical parametric oscillator based infrared spectroscopy for sensitive molecular gas sensing

Over the past 10 years, with the advent of new crystals designs and a new generation of pump lasers, continuous‐wave (cw) optical parametric oscillators (OPOs) have developed into mature monochromatic light sources. Nowadays, cw OPOs can fulfill a wide variety of criteria for sensitive molecular gas sensing. It can access the mid‐infrared wavelength region, where many molecules have their fundamental rotational‐vibrational transitions, with high power. This high power combined with wide wavelength tuning and narrow linewidth creates excellent conditions for sensitive, high‐resolution spectroscopy. OPOs combined with robust methods, such as photoacoustic spectroscopy and cavity‐enhanced spectroscopy, are well suited for field measurements and remote‐sensing applications. The wide tunability of cw OPOs allows detection of larger molecules with broad absorption band structures, and its fast scanning capabilities allow rapid detection of trace gases, the latter is a demand for life‐science applications. After a short introduction about the physical principle of cw OPOs, with its most recent physical developments, this review focuses on sensitive molecular gas sensing with a variety of spectroscopic applications in atmospheric and life sciences.     

Apatite-structure crystal, Yb(3+):SrY(4)(SiO(4))(3)O, for the development of diode-pumped femtosecond lasers

We report what is believed to be the first diode-pumped Yb(3+): SrY(4)(SiO(4)) (3)O laser. We investigate both the cw and the mode-locked regimes. In the cw regime an average output power of 1.05 W is demonstrated for 3.6 W of incident pump power. In the femtosecond regime a pulse duration of 94 fs for an average power of 110 mW is obtained at a central wavelength of 1068 nm. This is, to our knowledge, the first femtosecond mode-locked oscillator made with an Yb-doped apatitelike crystal. These properties are related to the unique spectroscopic properties of Yb(3+) ions in this atypical apatite-family crystal.     

Continuous-wave, single-frequency, solid-state blue source for the 425-489 nm spectral range

We report a new source of cw, single-frequency radiation in the blue, offering extended tunability and practical powers in a compact, all-solid-state design. The device is based on a green-pumped, cw, singly resonant optical parametric oscillator using MgO-doped stoichiometric lithium tantalate (MgO:sPPLT) as the nonlinear material. By internal second-harmonic generation of the resonant near-infrared signal radiation in a 5 mm BiB(3)O(6) crystal, we generate nearly 450 mW of cw, single-frequency blue power over a tunable range of 425-489 nm with a linewidth of 8.5 MHz and a Gaussian spatial beam profile. The demonstrated wavelength coverage can be further extended by using alternative gratings for the MgO:sPPLT crystal.     

Low Power Penalty Operation of a Wide Input Dynamic Range Cross-Phase Modulation Wavelength Converter

We successfully demonstrated low power penalty operation of a cross-phase modulated (XPM) wavelength converter using a semiconductor optical amplifier (SOA) power equalizer. We also clarified the SOA equalizing level for more adaptive wavelength conversion and achieved a power penalty of less than 1 dB over the wide input dynamic range of 15 dB.     

激光热诱导PbS纳米微粒的自陷、衍射和自散焦现象

用波长为488nm的氩离子激光与聚乙烯吡咯烷酮(PVP)修饰的PbS纳米微粒水溶胶作用,观察到了样品的自陷、衍射和自散焦现象,样品的折射率为负。测量了自陷阈值功率,计算了样品的非线性折射率n2。样品响应时间为11.86ms,且对488nm波长的光有吸收,说明样品的上述现象主要是由激光热诱导折射率的改变所引起的。     

Theoretical investigation of the input power dynamic range enhancement of XPM wavelength converter using a CW holding beam

The performance of pre-amplified cross-phase modulation (XPM) wavelength converter with a continuous wave (CW) holding beam has been theoretically investigated. To increase the input power dynamic range of the pre-amplified XPM wavelength converter, we apply a CW holding beam to the pre-amplifier of XPM wavelength converter. In our proposed scheme, the input power dynamic range with negative power penalty of 20dB was obtained.     

Operational and design considerations for broad area graded barrier quantum well heterostructure lasers grown by metalorganic chemical vapor deposition for high power applications

Graded barrier quantum well heterostructure (GBQWH) broad area lasers have been shown to be capable of high power pulsed and cw operation. In this article, we consider several operational characteristics and design issues associated with broad area graded barrier quantum well heterostructure lasers grown by metalorganic chemical vapor deposition. In particular, the effect of junction heating on emission wavelength for cw device operation and the effects of various buffer layer structures on the material properties and device characteristics of GBQWH structures are addressed. Typical results for high power operation of uncoated broad area laser diodes are also outlined.     

Stable high-power continuous-wave Yb(3+)-doped silica fiber laser utilizing a point-by-point inscribed fiber Bragg grating

We report on a narrowband 5 W cw fiber laser incorporating a point-by-point fiber Bragg grating inscribed into the core of a Yb(3+)-doped double-clad fiber. The laser featured excellent long-term wavelength and power stability (0.3%), as well as a very narrow (15 pm) linewidth, when passive temperature stabilization of the grating was implemented.     

Operational and design considerations for broad area graded barrier quantum well heterostructure lasers grown by metalorganic chemical vapor deposition for high power applications

Graded barrier quantum well heterostructure (GBQWH) broad area lasers have been shown to be capable of high power pulsed and cw operation. In this article, we consider several operational characteristics and design issues associated with broad area graded barrier quantum well heterostructure lasers grown by metalorganic chemical vapor deposition. In particular, the effect of junction heating on emission wavelength for cw device operation and the effects of various buffer layer structures on the material properties and device characteristics of GBQWH structures are addressed. Typical results for high power operation of uncoated broad area laser diodes are also outlined.     

Diode pumping of a continuous-wave Pr3+-doped LiYF4 laser

We report, for the first time to our knowledge, diode-pumped cw laser oscillation of Pr3+:LiYF4 in the red spectral range. The pump power is provided by a GaN laser diode emitting a maximum output power of 25 mW at a wavelength of approximately 442 nm. The Pr3+ laser emits 1.8 mW of output power at a 639.7-nm wavelength. Threshold pump power and slope efficiency in a nonoptimized setup are determined to be 5.5 mW and 24%, respectively.     

Supercontinuum generation in short tellurite microstructured fibers pumped by a quasi-cw laser

We investigate supercontinuum (SC) generation in highly nonlinear tellurite microstructured fibers pumped by a continuous wave (cw)/quasi-cw laser. We investigate two types of tellurite fibers. One type has the constant core diameter, and the other type has a longitudinally varying core diameter. For the fibers with a constant core diameter, when pumped in the anomalous dispersion region, the SC is symmetric in a fiber that has a zero dispersion wavelength close to the pump wavelength. For the fibers with a longitudinally varying diameter, the calculated phase-matching conditions show that they have a broad wavelength range of dispersive waves, and therefore the measured SC spectrum can be broader than one octave. In this work, the fiber lengths are as short as several tens of centimeters, and the pump power is in the watt level.     

Diode-pumped femtosecond Yb:KGd(WO(4))(2) laser with 1.1-W average power

We demonstrate what is to our knowledge the first mode-locked Yb:KGd(WO(4))(2) laser. Using a semiconductor saturable-absorber mirror for passive mode locking, we obtain pulses of 176-fs duration with an average power of 1.1 W and a peak power of 64 kW at a center wavelength of 1037 nm. We achieve pulses as short as 112 fs at a lower output power. The laser is based on a standard delta cavity and pumped by two high-brightness laser diodes, making the whole system very simple and compact. Tuning the laser by means of a knife-edge results in mode-locked pulses within a wavelength range from 1032 to 1054 nm. In cw operation, we achieve output powers as high as 1.3 W.     

Fiber-laser-pumped continuous-wave singly resonant optical parametric oscillator

We report on what is to our knowledge the first continuous-wave (cw) optical parametric oscillator (OPO) that is pumped by a tunable fiber laser. The OPO is singly resonant for the signal wave and consists of a 40-mm-long periodically poled LiNbO(3) crystal in a four-mirror ring cavity. At a pump power of 8.3 W provided by the wavelength-tunable Yb-doped fiber laser, the singly resonant OPO generates 1.9 W of 3200-nm cw idler radiation. The singly resonant OPO was tuned from 1515 to 1633 nm (signal) and from 3057 to 3574 nm (idler) by means of the crystal temperature and poling period. We obtained a wide idler tuning range, from 2980 to 3700 mn, by tuning the wavelength of the fiber laser from 1032 to 1095 nm.