1,720,964 research outputs found
Modelling of Y-junction waveguide resonators
No full textRare-earth-doped multiple-cavity waveguide lasers driven by on-chip phase modulators comprise a new class of integrated optical sources. In this paper, a transfer matrix model suitable for the analysis of multiple-cavity resonators is developed and used to investigate the spectral characteristics of a resonator incorporating a Y-junction. This resonator is shown to be suitable for the realization of monolithically integrated Q-switched, line-narrowed. and tunable planar waveguide lasers
Rare-earth doped planar waveguide lasers
No full textRare-earth doped planar waveguide lasers have been realised in many host materials, using a range of waveguide fabrication techniques. Laser action has been obtained in ion-implanted Nd-doped crystals such as YAG, YAP, LiNbO3, & BGO, in proton-exchanged and titanium indiffused waveguides in Nd- and Er-doped LiNbO3, in Nd- and Er-doped silica waveguides on silicon, in Nd-doped sputtered glass waveguides, and in ion-exchanged Nd-doped glass waveguides. Each of these materials systems has specific advantages either as a laser host, or because of the potential for increased functionality through use of electro-optic effects, for example. Recent advances in this technology exploit the advantages that planar devices have over fibre devices. In particular, acousto-optic, electro-optic, or thermo-optic modulators may readily be monolithically integrated, complex multiple cavity devices may be defined photolithographically, there is access to the waveguides for surface interactions, and waveguide geometries may be changed along the device for efficient interfacing to external components and optimisation of individual devices. Recently, an FM mode-locked waveguide laser in Nd-doped LiNbO3 with an integral modulator), and a waveguide laser in LiNbO3 with locally diffused erbium have been demonstrated. The particular importance of the latter development is that passive waveguide components may be realised on the same substrate as those with gain
Optoelectrochemical transduction on planar optical waveguides
No full textPlanar optical waveguides overlaid with electrochemically-modulated sensing films comprise a powerful new class of chemical transducer. In this paper, the effects upon the modal absorption spectrum of depositing a highly absorbing electrochromic film on an optical waveguide are modelled. Theoretical and experimental results are given for such a device consisting of a lutetium biphthalocyanine film deposited on an indium tin oxide-coated potassium ion-exchanged glass waveguide, for application as a chlorine sensor
Laser diode pumped waveguide lasers in neodymium-doped BK-7 glass
No full textIon-exchange in neodymium doped glasses has been used to fabricate waveguides which were optically pumped to realise lasers. The application of these layers as light sources in glass substrates will enhance the functionality of integrated optic systems in glass, allowing integration of active and passive devices. To obtain practical light sources, the neodymium-doped waveguides must be laser diode pumped to provide compact laser systems. Since the power available from a single stripe laser diode is limited, it is necessary to design the waveguide so that its modal field pattern matches that of the laser diode, thereby minimising the pump power required from the laser diode for the waveguide laser to reach threshold. We report on the fabrication and characterisation of waveguide laser pumped with a laser diode. These lasers operated in a continuous wave at a wave length of 1059nm, and were single transverse mode at both the pump and lasing wavelengths. The variation of the waveguide laser thresholds with the waveguide dimensions reveals the existence of an optimum dimension which minimises the laser threshold. A laser threshold of 20mW from the pump source and an overall slope efficiency of 5% with respect to the laser diode output power was obtained
Integrated Q-switched multiple-cavity glass waveguide laser
No full textA novel Q-switching scheme, using rapid variation of the path difference between the cavities of a multiple-cavity resonator, is demonstrated. A thermo-optic phase modulator was used to switch the cavity loss of a Y-junction glass waveguide laser between high and low states. Q-switched pulses with durations of 5µs and peak powers of 70mW were obtained
Tunable line-narrowed lasers employing Y-junction waveguide resonators
No full textRare-earth-doped planar waveguide lasers have been realised in many host materials, using a range of waveguide fabrication techniques. Recent advances in this technology exploit the advantages that planar devices have over fibre devices. In particular, electro-optic or thermo-optic modulators may readily be monolithically integrated, complex devices may be defined photolithographically, there is access to the modal fields for surface interactions, and waveguide geometries may be varied along the device for efficient interfacing to external components and for optimisation of individual components on an optical "chip"
Low-threshold monomode ion-exchanged waveguide lasers in neodymium-doped BK-7 glass
No full textThe ion exchange technique has been advanced as method of fabrication of active integrated optic devices in glass substrates. Multimode waveguides have previously been made in rare-earth doped glasses and optically pumped to provide amplifying media or lasers. However lasers fabricated using single-mode waveguides have lower thresholds than multimode devices. In this paper we report the first demonstration of a monomode ion exchanged laser in neodymium doped BK-7 glass. The technique is suitable for batch processing of devices at low cost. In addition the waveguide fields can be easily perturbed in the planar geometry enabling a variety of devices such as modulators, ring and coupled-cavities, and wavelength multiplexers to be integrated. Development of active integrated optic devices in glass has been hampered by lack of rare-earth doped glasses with suitable ion exchange chemistry. In our case this drawback has been removed by selecting an ion-exchangeable glass and doping it with the required rare-earth ions. This also allows variation of the dopant concentration to optimise laser performance. BK-7 was chosen as the basic glass because of its good optical quality and excellent ion exchange properties with silver, potassium and caesium ions which allow waveguides with a wide range of numerical apertures to be easily fabricated. In our studies BK-7 glass was doped with 2 wt% neodymium oxide to form the substrate. Single-transverse-mode waveguide lasers were fabricated in the substrate by potassium ion exchange
Erbium-doped ion-exchanged waveguide lasers in BK-7 glass
No full textIon exchange in glass is a simple, flexible, technique to realize optical fiber compatible planar waveguide devices. Recently, neodymium-doped waveguide lasers operating at 1060 and 1300 nm have been demonstrated in this technology. Lasers operating at 1540 nm are desirable for telecommunication applications and we report here, for the first time, ion-exchanged waveguide lasers in erbium-doped glass emitting at this wavelength. Lasers in BK-7 glass doped with 0.5 wt% Er2O3 and pumped at 980 nm exhibited launched pump power thresholds of 150 mW and slope efficiencies of 0.55%. The waveguides operated in a single transverse mode at the lasing wavelength
Neodymium-doped ion-exchanged waveguide lasers in BK-7 glass
No full textThe availability of integrated optical sources in glass is expected greatly to enhance optical signal processing in glass substrates. In this paper, we report on a study of potassium ion-exchanged waveguide lasers in neodymium-doped BK-7 glass substrates. Design parameters for low-threshold waveguide lasers with high slope efficiencies are described, and methods are given for the fabrication of substrates, waveguides and laser cavities. Properties of the substrates, waveguides and the resulting lasers are presented in detail
Fluorescent lifetime of Er<sup>3+</sup> <sup>3</sup>I<sub>13/2</sub> level in BK-7 borosilicate glass
No full textIt is established that the B3+ ions exist only in the form of [BO4] units in BK-7 borosilicate glass. This limits the maximum vibrational energy at peak to 1200 /cm rather than 1400 /cm, as is found in borate glasses, and explains the long lifetime of the Er3+ 4I13/2 level observed in BK-7 borosilicate glass
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