2×2 InGaAsP/InP laser amplifier gate switcharrays using reactive ion etching

Monolithically integrated 4×4 semiconductor laser amplifier gate switch arrays comprising 24 integrated laser amplifiers have been fabricated and evaluated. Net positive optical gain between fibres, high extinction ratio, and low crosstalk are reported.

Monolithically integrated 4×4 semiconductor laser amplifier gate switch arrays comprising twenty-four integrated laser amplifiers have been fabricated and evaluated. We report observation of net positive optical gain between fibres, high extinction ratio, and low crosstalk.

Monolithically integrated 2*2 semiconductor laser amplifier gate switch arrays have been fabricated and evaluated. Net positive chip gain, high extinction ratio, and high electrical isolation between the integrated laser amplifiers are reported.

Monolithically integrated 4/spl times/4 semiconductor laser amplifier gate switch arrays comprising twenty-four integrated laser amplifiers have been designed, fabricated, and evaluated. Low fiber-to-fiber loss, low polarization dependence, high extinction ratio, and low crosstalk are reported. >

Summary form only given. The switch arrays operating at 1.3 /spl mu/m wavelength are fabricated integrating passive and active InGaAsP-InP semiconductor waveguides by a stable fabrication process based on metal organic vapor phase epitaxy (MOVPE) and reactive ion etching (RIE). After 1st growth of active layers and RIE etching of passive parts, the passive layers were grown for butt-coupling. The passive and active waveguides were prepared by RIE process. We also achieved the integrated amplifiers with the high performance and good uniformity by the same fabrication method.

An InGaAsP-InP 2*2 laser amplifier gate switch matrix operating at 1.5 mu m with a fiber-to-fiber insertion loss of 3 dB is reported. The switch consists of passive waveguides for branching and recombining, monolithically integrated with laser amplifiers. The passive waveguides perform the signal routing, and the amplifiers provide gain/absorption in each path for on/off switching, achieving gain in the on state to compensate the losses. Dry-etched total internal reflection mirrors are employed as 90 degrees waveguide corner mirrors and also incorporated in the splitters in order to give a compact design. The on/off extinction ratio is >45 dB and the crosstalk is <-45 dB.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Semiconductor optical amplifiers have been used as key optical components for high capacity communication systems. Monolithic integration is necessary for the stable operation of these devices and for wider applications. In this paper, the coupling technique between different waveguides was discussed and research results about optical devices integrated with SOAs were presented. In particular laser amplifier gate switch arrays have been discussed.

Novel thermo-optic waveguide gate switch arrays were designed and fabricated based on the direct UV-written technique. Highly fluorinated low-loss photopolymers and organic-inorganic grafting materials were used as the waveguide core and cladding, respectively. The low absorption loss characteristics and excellent thermal stabilities of the core and cladding materials were obtained. The rectangular waveguides and arrayed electrode heaters have been theoretically designed and numerically simulated to realize single-mode transmission. The propagation loss of a 4-μm-wide straight waveguide was measured as 0.15 dB/cm. The insertion loss of the device was directly measured to be about 5.5 dB. The rise and fall times of the device applied 100 Hz square-wave voltage were obtained as 1.068 and 1.245 ms, respectively. The switching power was about 9.2 mW, and the extinction ratio was 17.8 dB. The low-loss integrated switch arrays are suitable for realizing large-scale photonic integrated circuits.

Digital transmission experiments at 2.488 Gbit/s involving a monolithic 4 × 4 semiconductor laser amplifier gate switch array operating at around 0 dB fibre-to-fibre gain have been performed. Receiver power penalties less than 1 dB are reported for a switch input power range in excess of 10 dB. Results on switch saturation include a switch signal output power, coupled to the output fibre, of – 5 dBm for 3 dB gain compression of the 4 × 4 switch.

Chapter 6 - PLC-type Thermooptic Switches for Photonic Networks

Optical bistability (OB) in passive nonlinear etalons such as those containing multiple quantum wells (MQW) of GaAs/AlGaAs is a promising alternative to other bistable optical switching mechanisms such as those which occur in semiconductor lasers and laser amplifiers [1]. Although OB in passive nonlinear etalons is somewhat slower, it is much more easily extendable to one- and two-dimensional arrays of switches. To realize this advantage, it is necessary to minimize the switching thresholds and optical absorption (and hence the power dissipation) in the MQW etalon. Following an approach which has already proven successful in reducing thresholds and increasing power efficiencies of vertical-cavity surface-emitting semiconductor lasers (VCSELs) [2], here we consider a MQW structure with several quantum wells (or closely-spaced groups of quantum wells) spaced one-half wavelength apart in the resonant cavity, positioned so that they align optimally with the antinodes of the standing wave optical field in the etalon. We have analyzed the system numerically using a wave propagation model in a thin-film matrix formalism. The spacers are assumed to have constant indices, the unsaturated QW absorption α0 follows the semi-empirical description of Chemla et al. [3], and the excitonic features saturate according to the simple rule α(I) = α0/(1 + I/Isat). In contrast to the situation where optically-pumped lasing occurs, here the spacers are non-absorbing and the input optical beam(s) for holding and switching are tuned close to the heavy-hole excitonic absorption peak in the quantum wells. As in the VCSEL, significant excitation of the quantum wells occurs primarily along the cavity axis, reducing the switching threshold. This reduction, together with the low background absorption of the structure, should enable efficient arrays of bistable optical switches to be constructed.

Summary form only given. The increase of the channels in wavelength-division multiplexing (WDM) in optical systems will make possible reconfigurable and transparent WDM networks, such as ring networks with wavelength-division add-drop multiplexer (WD-ADM). The most crucial issue for the WD-ADM system is the limitation of the cascaded-node count caused by passband-frequency misalignment of wavelength multiplexers/demultiplexers. For example, cascadability performance of an arrayed waveguide grating (AWG) spaced at 100-GHz interval is practically limited to several spans. In this paper, we propose a novel WD-ADM configuration using a single AWG and back-reflecting-type Er/sup 3+/-doped fiber amplifier (EDFA) gate switches, which improves the allowable cascaded-node count. The feasibility of the proposed WD-ADM configuration has been confirmed through experiments, and the cascadability of nodes has been estimated.

All-optical switching and multiple logic gates are experimentally demonstrated using AlGaInAs/InP hybrid square-rectangular lasers. Controllable bistability induced by saturable absorption in the square microcavity is achieved around the threshold with the square cavity in an open circuit state. Based on the bistability, all-optical switching operation is realized by injecting set/reset optical signals with the wavelengths around the lasing mode of 1529.9 nm and another high-Q mode at 1560 nm. Furthermore, mode competitions between three resonant modes around 1541 nm with an interval of 1.2 nm are used to realize all-optical multiple logic gates of NOT, NOR, and NAND functions under low-power optical pulses, with injecting currents to the square and rectangular sections. The static extinction ratio of 34, 40 and 24 dB are obtained for NOT, NOR, and NAND gates, respectively, and the dynamic extinction ratio over 10 dB of NOT function at 15 Gb/s, NOR and NAND functions at 2 Gb/s are demonstrated. With the merits of multifunctional operations, large optical injection wavelength tolerant ranges, low power consumption, small footprint and suitability for on-chip integration, the device offers a potential solution for all-optical signal processing in photonic integration circuits.

We report a compact integrated 2.x2 laser amplifier gate switch matrix with 4dB fibre-to-fibre loss. Total internal re .flection mirrors are incorporated to achieve a small, low loss device suitable for large scale integration.

A 4×4 semiconductor optical amplifier gate switch matrix was fabricated by integrating undoped upper-cladded waveguides with buried ridge stripe semiconductor optical amplifiers. The undoped upper cladding was used to prevent the high propagation loss of the conventional p-cladded waveguides. The 4×4 switch showed positive fiber-to-fiber gain with only two integrated optical amplifiers per transmission path and all sixteen transmission paths showed uniform characteristics.