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Compact monolithic single-mode red emitting diode lasers are still not readily available for many wavelengths in the visible spectrum. Strontium lattice and Calcium clocks are some of the most widely investigated optical clocks worldwide and the pertinent transitions wavelengths required are in the red and blue wavelength spectral region. The current state of the art in laser technology employs external...
Direct UV written planar waveguides in silica have been explored for over two decades [1]. The technique is capable of fabricating low-loss channel waveguides, couplers and Bragg gratings by translating an appropriate substrate through a focused UV beam. To date direct UV written waveguides have been primarily formed by using 244nm laser light, relying on the photosensitivity provided by germanium...
Diamond is an exceptional material due to its hardness, high thermal conductivity and transparency from the UV to far IR. Recently it has caught the attention of the scientific community because it is the host of different color centers that can be used for magnetic sensing applications and quantum computing [1]. One of the most promising of these defects is the nitrogen-vacancy (NV) center. The electrons...
Compact pulsed laser sources are of interest for diverse application areas. Due to their broad gain bandwidth, high Stokes efficiency and low thermal load near the 1 μm spectral region, ytterbium doped laser materials are promising for such devices. Channel waveguides in such gain media provide compact laser systems and deliver efficient single-mode laser operation with low laser thresholds. One of...
Bragg gratings were inscribed on the surface of thin GaN film grown on a sapphire substrate. These gratings are generated by illumination of 800 nm femtosecond pulses through a phase mask and a cylindrical lens.
Short-reach, low-cost, and large-capacity optical transport systems can be realized by using the T-band (1000–1260 nm) because it has five times wider bandwidth than that of the C- and L-bands combined [1]. In this study, we developed a wavelength-selective external cavity laser using an InAs quantum dot (QD) gain chip and a planar lightwave circuit (PLC) for T-band communications [2]. Fig. 1 shows...
The development of mid-infrared (λ∼3–20 μm) integrated optical sensors has accelerated within the last years. The main driving interest is the potential of using photonic integrated elements capable of direct interaction with biomolecules and chemicals through their ground molecular vibrational modes, so that resonance fingerprints are exploited for novel sensor industrial applications. State-of-the-art...
We demonstrate that a novel family of miniaturized deformed helix ferroelectric liquid crystal cells that has recently been developed in the context of distributed optical sensing networks can also be used to realize fully monolithic, actively Q-switched waveguide lasers as well as actively mode-locked all-fiber lasers. Those cells enable the development of pulsed laser sources with the same level...
The intrinsic properties of silicon (Si) make it an excellent material for integrated photonics devices with small footprints [1]. To date, most of the reported devices have been based on crystalline silicon (c-Si), but this material suffers from difficult integration with electronic layers due to fabrication constraints. Subsequently, there has been growing interest in alternative forms of Si, such...
Short distance optical communication is required to reduce power consumption of ICT systems and continuously improve performance of datacentres and HPCs [1]. Reduced energy consumption and increased bandwidth density [2-3] are required to develop optical interconnects between chips and on chips. Therefore, lasers and detectors with ultra-low operating energy have to be connected by Si nanowire waveguides...
Polycrystalline silicon (poly-Si) has attracted significant interest in the area of silicon photonics because of its potential for combining good optical transmission, electronic functionality and low fabrication cost, which makes it an attractive material for commercial applications [1]. In addition, it was shown recently that by laser processing of amorphous Si (a-Si) it is possible to obtain very...
Femtosecond laser machining combined with chemical etching offers an efficient and accurate way for producing complex three-dimensional structures out of fused silica. The versatility of the femtosecond laser machining together with the properties of fused silica makes it an ideal tool for integrating of micromechanical [1], microfluidic [2] and optical [3] devices, using the same fabrication method.
Er3+ doped single-crystalline layers are particularly interesting active media for compact waveguide lasers emitting at 1.5–1.6 μm [1]. Recently bulk monoclinic potassium double tungstates KRE(WO4)2 (RE = Y, Gd, Lu) have been shown to be excellent laser hosts for erbium ions, demonstrating efficient laser performance under direct in-band pumping into 4I13/2 energy level [2]. However, the highest doping...
Optical frequency combs (OFCs) generated by quantum cascade lasers (QCLs) have recently been proven in the mid infrared [1] and they have already been applied to spectroscopy in free-running operation [2]. It is clear however that for more demanding applications such as high-resolution and accuracy spectroscopy and metrology the performance obtained in free-running operation is not enough, since a...
Lithium niobate (LN) is one of basic materials of integrated optics used, for example, for electro and acousto-optical modulators, switches, diffraction gratings, nonlinear optical wavelength converters, and others [1]. LN-based ion exchange or Ti-indiffused photolithographic techniques are established technologies, however, some modern applications, such as high-purity suppressed carrier synthesis...
Photonic crystals have been used to provide fundamental control over the interaction between light and matter, including stimulated emission. For example, in Bloch-mode lasers, the photonic crystal provides field enhancement through reduced group velocity and offers larger mode volumes through distributed feedback [1]. In a photonic free-electron laser (pFEL) [2], where electrons stream through a...
In this paper the recent advances in waveguide lasers fabricated by ultrafast laser inscription (ULI) are reported with the focus on Yb:YAG waveguide based lasers in two different operation regimes. Watt level output powers in single longitudinal mode (SLM) as well as modelocked (ML) operation are demonstrated.
There is increasing demand for low noise, narrow linewidth lasers for applications including spectroscopy, ion traps for optical clocks and gravitational waves measurements. External cavity diode lasers (ECDL) can provide a compact, low cost solution; however these are typically available at a limited range of optical frequencies. The increase in applications requiring robust laser systems (e.g. space...
Ultrafast laser inscription (ULI) allows the fabrication of compact, highly-efficient and robust laser sources over a broad range of crystalline, ceramic and glass gain media. For instance, subsurface waveguides can be formed by the stress induced refractive index modification effect which takes place between two parallel modified regions referred to as “Type II” guiding [1]. Previously, a family...
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