K. Wunstel

Integrated interferometric injection laser: novel fast and broad-band tunable monolithic light source

A wide-range electronically wavelength-tunable InGaAsP-InP laser has been developed. This monolithic single-mode light source is based on interferometric principles. The authors report on successful fabrication and first experimental device characteristics obtained with these novel Y-coupled-cavity integrated interferometric injection lasers. For both the 1300 and 1500 nm wavelength regions, very large tuning ranges for 22 and 23 nm. respectively, were achieved by proper current adjustment. The minimum achieved linewidth of the nonoptimized devices is 35 MHz. Within the complete tuning range, the selection of 12 individual single-mode channels spaced by 2 nm is demonstrated with high-modulation bandwidths up to 5 GHz. A preliminary test of the wavelength switching behavior between two individual single modes indicates promising high-speed switching capabilities in the gigahertz range. >

10 Gb/s wavelength conversion with integrated multiquantum-well-based 3-port Mach-Zehnder interferometer

All-optical wavelength conversion of 10 Gb/s data with simultaneous regeneration of the extinction ratio is achieved by means of a monolithic 3-port Mach-Zehnder interferometer. The reported devices are based on an all active multiquantum-well waveguide structure with optical amplifiers in the input/output gates. Wavelength conversion is realized by optical cross-phase modulation in a counter propagative operation mode without applying an optical filter. The 3-port Mach-Zehnder interferometer can provide either inversion or noninversion of wavelength converted 10 Gb/s data.

All optical wavelength conversion schemes for increased input power dynamic range

Schemes for increasing the input power dynamic range of interferometric wavelength converters are presented with experiments at 10 Gb/s showing large improvements. A simple conversion scheme that uses current control of the interferometer improves the dynamic range from /spl sim/3-/spl sim/8 dB. A simpler method of inserting an Er-doped fiber amplifier (EDFA) before the converter results in more than 40 dB of dynamic range while a method of using a semiconductor optical amplifier (SOA) for power control gives /spl sim/28-dB dynamic range.

The Y-laser: a multifunctional device for optical communication systems and switching networks

This paper gives a comprehensive review of the recent progress obtained with various operation modes of a Y-shaped all active waveguide device with three optical input/output ports, the so called Y-laser. Used as a monolithic semiconductor light source, single-mode emission with an extremely large cw tuning range of more than 50 nm is accessed. Single current step tuning spans up to 8-nm range. Several-GHz bandwidth AM and FM response is achieved. Operation as a wavelength processing device is demonstrated with data-stream transformation from short wavelength fiber windows (around 780 nm or 1310 nm) to the long wavelength window (1550 nm), as well as with ultra wide range wavelength conversion within the 1550-nm region, across +/-20 nm (blue and red shift). Optical high-speed space switching/gating functions are verified up to 1 Gb/s, and packet switching of 5-Gb/s data streams is demonstrated. Further features as a pulse reshaping device, as an electrically triggerable wavelength bistable device and as a mode locked pulse generator are addressed. Possible applications of this multifunctional device in future optical communication systems and switching networks are discussed. >

Multifunctional photonic switching operation of 1500 nm Y-coupled cavity laser (YCCL) with 28 nm tuning capability

The authors present new results on extended electrical tuning, fast spatial switching, and optically controlled wavelength conversion characteristics for the recently developed InP-based Y-laser structure. The devices have a 80 nm thick bulk InGaAsP active layer and are completely grown by metalorganic vapor phase epitaxy. The facets at both ends of the chip are as-cleaved without antireflective coating. The addressable range for electrically controlled wavelength switching was extended to the record value of 28 nm. When operated as a lossless 1:2 optical space switch, fiber-to-fiber gain >0 dB, extinction ratio >50 dB and high speed operation up to 1 Gb/s were shown. Optically triggered tunable wavelength conversion including dynamic operation was also demonstrated.<<ETX>>

6 THz range tunable 2.5 Gb/s frequency conversion by a multiquantum well Y laser

Improved monolithic interferometric semiconductor lasers in Y configuration are reported. When they are operated as electrically tunable light sources, single-longitudinal-mode emission with a very large CW tuning range up to 51 nm is obtained. By using all-quaternary compressively strained multi-quantum-well (MQW) active layers, low DC threshold currents down to >

10 Gbit/s monolithic MQW-based wavelength converter in Michelson interferometer configuration

Summary form only given. In conclusion, we have reported on the first successful 10 Gbit/s operation of a compact MQW interferometric wavelength converter. The bandwidth was increased compared to previously reported MQW-based structures taking advantage of higher differential gain and optical confinement factor as achieved by optimizing the MQW layer structure.

WDM cross-connect cascade based on all-optical wavelength converters for routing and wavelength slot interchanging using a reduced number of internal wavelengths

Summary form only given. Optical transport layers need rearrangeable wavelength-division multiplexing optical cross-connects (OXCs) to increase the capacity and flexibility of the network. It has previously been shown that a cross-connect based on all-optical wavelength converters for routing as well as wavelength slot interchanging can be used to create a robust and nonblocking OXC. However, for an OXC with n fiber inlets each carrying m wavelengths the OXC requires n/spl times/m internal wavelengths, which constrains the size of the cross-connect. In this paper we therefore propose and demonstrate an architecture that uses a reduced set of internal wavelengths without sacrificing cross-connecting capabilities. By inserting a partly equipped OXC with the new architecture in a 10-Gbit/s re-circulating loop setup we demonstrate the possibility of cascading up to ten OXCs. Furthermore, we investigate the regenerating effect of the OXC on signals that suffer from interferometric crosstalk.

Impact on traffic and transmission performance of all-optical wavelength converters placed at the network interface or in OXCNs

In summary, placing optical wavelength convertors (OWCs) in the optical cross connecting nodes (OXCN)s rather than at the fibre network interface not only improves the traffic performance but also enhances the performance of the physical layer, e.g., in terms of relaxed cross talk requirements.

All-optical 40-Gbit/s compact integrated interferometric wavelength converter

An interferometric Michelson wavelength converter is presented that combines a speed-optimized semiconductor optical amplifier technology with the benefits of the integrated interferometer showing 40-Gbit/s wavelength conversion. The optimized wavelength converter demonstrates noninverted converted signals as well as converts to both shorter and longer wavelengths. Excellent results are achieved with /spl sim/10 dB extinction ratio and more than 25 dB signal-to-ASE (amplified spontaneous emission) ratio (1 nm) for the converted signals at 40 Gbit/s.