Slab Waveguide Laser Research Articles

Operation of an InAs quantum-dot embedded GaAs photonic crystal slab waveguide laser by using two-photon pumping for photonics integrated circuits

The development of small sized laser operating above room temperature is important in the realization of optical integrated circuits. Recently, micro-lasers consisting of photonic crystals (PhCs) and whispering gallery mode cavities have been demonstrated. Optically pumped laser devices could be easily designed using photonic crystal-slab waveguides (PhC-WGs) with an air-bridge type structure. In this study, we observe lasing at 1.3μm from two-photon pumped InAs-quantum-dots embedded GaAs PhC-WGs above room temperature. This type of compact laser shows promise as a new light source in ultra-compact photonics integrated circuits.

Class of resonator for slab waveguide lasers.

We describe a class of laser resonator, incorporating a feedback collimator (FBC), that provides feedback that is mode-matched onto a higher-order lateral mode of a slab waveguide laser. In addition, this same resonator, in outcoupling, converts the stabilized higher-order lateral mode into an essentially laterally collimated output beam with a width that exceeds twice the width of the laser-active region. This output beam should have excellent beam quality. Here, we develop the FBC resonator design principles and describe both refractive and reflective versions. Finally, we compare the efficiencies and thresholds of an FBC resonator and an angled-ridge resonator applied to a broad-ridge quantum cascade laser.

Tm3+-based waveguide lasers in monoclinic double tungstates

We review our recent results on the fabrication and characterization of Tm3+-based waveguide lasers on monoclinic potassium double tungstates. We demonstrated laser oscillation in the CW regime, at ∼1.84μm, in slab and channel waveguides. In addition, using such guiding layers, we have demonstrated passive Q-switching in a slab waveguide laser.

Integral plug-in RF module in a CO 2 hybrid-waveguide laser: Its performance and overall evaluation

This work describes the performance of a compact “in-house built” radio–frequency (RF)-excited CO 2 slab waveguide laser which has the innovation of having a plugged-in RF generator–amplifier module directly connected into the positive electrode of the laser head. The design circuit parameters include a matching circuit and a feed-through element as a whole. The overall laser performance takes into account the waveguide dimension ( y-axis) as approximately one-tenth of the free space transverse dimension ( x-axis). The optical resonator is calculated to be in the regime of the negative branch for unstable confocal resonators, having focal lengths of f 1 = 21.49 cm and f 2 = 19.39 cm with geometrical amplification of 1.108. Optical output coupling mirror was set to ∼9.7%. The calculated waveguide length is 37.73 cm whilst the total resonator length was adjusted to 42 cm to allow coupling losses less than 1%. The laser operational efficiency was about 12% and the output beam quality of 1.13 which is close to the ideal Gaussian beam. The optical output power was accomplished by playing with different gas compositions to have a final optimized gas proportion of 1:1:2.7:0.3 correspondingly to CO 2, N 2, He and Xe as admixture.

A diode-bar side-pumped waveguide laser with an extended stable cavity for spatial mode control

We describe the use of an extended stable cavity to control the output spatial mode of a diode-bar side-pumped slab waveguide laser. The active medium consists of a Nd:YAG core with a one-dimensional double-clad guiding structure. The device gives >10 W output power with a 56% slope efficiency for multi-mode operation, which is reduced to 33% for the best output beam quality parameters ( M 2 values) of 2.8×1.1. The prospects for obtaining higher efficiencies and scaling to larger average powers are discussed.

RF Excited High Efficiency CO2 Slab Waveguide Laser Array with Multiple-Slot Optical Coupling

In this paper we report a high-efficiency phase-locked CO2 slab waveguide laser array with compact multisegment RF excitation. Composed of two 3×8×400 mm3 waveguide slabs, the laser array delivered a maximum output power of 115 W with efficiency up to 19.5%. Small signal gain and saturation power measurements indicated that the laser configuration is well suited for RF driving of a CO2 slab laser array. Multiple-slot optical coupling devised in the two-slab laser array also resulted in low insertion loss and high-field coupling between the slabs.

Output power optimisation of slab-waveguide laser with Gaussian output mirror

We present an approximate analysis of the nonlinear operation of the hollow slab-waveguide laser with Gaussian reflectivity profile output mirror, including gain saturation and longitudinal as well as transverse field distribution of the laser mode. The model presented is general and can be applied to the study of arbitrary configuration of the slab-waveguide laser. In particular, the laser characteristics obtained reveal the influence of the position of the output mirror and the Gaussian mirror parameter on the power efficiency of the laser system.

Algorithm of RF-excited slab-waveguide laser design

Basic mechanisms influencing the resonant frequency of the RF-discharged slab-waveguide CO2 laser head are described. An algorithm of calculations to design a laser headresonant frequency is given. The algorithm is experimentally confirmed.

Radio frequency discharge excited diffusively cooled kilowatt carbon monoxide slab waveguide laser with a three mirror resonator

In this letter, we describe a kilowatt radio frequency discharge excited diffusively cooled slab waveguide carbon monoxide laser, in which the top and bottom electrodes were cooled with liquid nitrogen and which utilized a modified resonator. With this design we obtained a maximum laser power output of 1020 W, which was 10% higher than the same device employing a conventional unstable resonator.

Kerr lens mechanism in a waveguide laser

We consider theoretically the Kerr lens mechanism for a slab waveguide laser operating in lowest order. The thin film geometry incorporates both soft and hard aperture functions. The results show that very high differential gain is available. We further show that a criterion for self-starting action is more easily met in the waveguide laser. We conclude that fully integrated, self-mode-locked solid state lasers are feasible.

Combined array/slab waveguie CO 2 lasers

A novel laser structure is described which combines RF excited slab waveguide and array laser concepts. A CO 2 device with a 7 channel array and Talbot imaging slab section excited simultaneously has produced 135 W of output.

Single-mode selection using coherent imaging within a slab waveguide CO2 laser

A technique for selecting a single high-order lateral mode of a rf excited slab waveguide laser is described. An in-cavity grid which matches the periodicity of the desired mode, together with slab waveguide dimensions which create coherent imaging by the Talbot effect, have produced a stable output power of 155 W in a high spectral purity, single-resonator mode.

Single-transverse-mode LiNdP4O12 slab waveguide laser

Argon-laser-pumped single-transverse-mode laser operation was obtained with a three-dimensionally confined LiNdP4O12 slab waveguide laser, in which one endface was cylindrically polished and directly coated with a laser mirror. The threshold, the output power, and the oscillating transverse modes were theoretically analyzed, both for transverse pumping and for longitudinal pumping, considering the spatial distribution of the pump beam and the laser beam. The necessary conditions for the pump sources to obtain a TE00 single-transverse-mode oscillation were determined on the supposition of the diode pumping.

A slab waveguide laser formed of glass-clad LiNdP4O12

A 60-μm-thick and 0.5-mm-long LiNdP4O12 slab waveguide laser clad by sputtered SK12 glass was fabricated. Single TE0-mode pulse and quasi-cw laser oscillations at 1.047 μm were obtained by longitudinal pumping with a rhodamine 6G laser and an argon laser, respectively. The round-trip waveguide loss was evaluated from the threshold pump pulse energy to be 0.035 for TE0-mode oscillation.