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The standardization of photonic integration processes for InP has led to versatile and easily accessible generic integration platforms. The generic integration platforms enable the realization of a broad range of applications and lead to a dramatic cost reduction in the development costs of photonic integrated circuits (PICs). This paper addresses the SMART Photonics generic integration platform developments. The integration technology based on butt joint active-passive epitaxy is shown to achieve a platform without compromising the performance of the different components. The individual components or building blocks are described. A process design kit is established with a comprehensive dataset of simulation and layout information for the building blocks. Latest results on process development and optimization are demonstrated. A big step forward is achieved by applying high-resolution ArF lithography, which leads to increased performance for AWGs and a large increase in reproducibility and yield. The generic nature of the platform is demonstrated by analyzing a number of commercial multiproject wafer runs. It is clear that a large variety of applications is addressed with more than 200 designs from industry as well as academia. A number of examples of PICs are displayed to support this. Finally, the design flow is explained, with focus on layout-aware schematic-driven design flow that is required for complex circuits. It can be concluded that generic integration on InP is maturing fast and with the current developments and infrastructure it is the technology of choice for low cost, densely integrated PICs, ready for high-volume manufacturing.

Progress on the development of a long wavelength (∼2 µm) generic monolithic photonic integration technology on indium phosphide substrate and a novel concept of a tunable laser realized as a photonic integrated circuit using such technology are presented. Insights into the development of active and passive waveguide structures which are used to define a limited set of on-chip functionalities in the form of building blocks will be given. A novel tunable laser was proposed and designed using such predefined set of basic building blocks. The laser geometry features an intra-cavity wavelength tuning mechanism based on asymmetric Mach-Zehnder interferometers in a nested configuration. The photonic integrated circuit chip was fabricated within the first long wavelength multi-project wafer run. The experimental evaluations of the fabricated device show a record tuning range of 31 nm around 2027 nm and successful measurements of a 0.86 GHz wide absorption line of carbon dioxide. These results provide a demonstration of a fully functional photonic integrated circuit operating at wavelengths that are much longer than those in the typical telecommunication windows as well as the use of indium phosphide based generic photonic integration technologies for gas sensing applications.

In this paper, we present the design, fabrication, and characterization of two monolithically InP-based integrated electro-optically tunable filters. The combination of these filters can be used to achieve a filter with a narrow passband and a large free spectral range. These filters are designed to be used in an integrated tunable laser source in the 1600-1800 nm wavelength region using active-passive integration technology. The fact that these filters worked successfully shows that this integration technology, originally designed to be used around 1550 nm wavelength, can also be used successfully in the 1600-1800 nm wavelength region without a large penalty in performance. The two filters, a high-resolution arrayed waveguide grating-type filters and a low-resolution multimode interferometer-tree-type filter are made tunable using 5 mm long electro-optic phase modulators in the arms of the waveguide arrays. Measurements show that these filters can be tuned over a wavelength range of more than 100 nm with an accuracy of 0.1 nm (1% of the free spectral range) for the high-resolution filter and an accuracy of 9 nm (4% of the free spectral range) for the low-resolution filter.

InGaAsP lasers with different losses have been investigated under hydrostatic pressure at room temperature. It is shown that, for large loss devices, the threshold current decreases more rapidly with increasing pressure than the expected variation of the typical direct band-to-band Auger recombination currents. We also measured the spontaneous emission in a large loss device to determine the pressure dependence of the respective recombination current component at laser threshold. It is found that the Auger current reduces strongly and the radiative current also decreases with increasing pressure. This is attributed to a reduction of the total loss coupled with Auger recombination with pressure.

From measurements of the threshold current and lasing energy as a function of pressure in InGaAsP/InP, AlGaInAs/InP and GaInNAs/GaAs based multiple quantum well lasers we determine the relative importance of the monomolecular, radiative and Auger recombination processes. For the InP based devices, we find that a simple combination of radiative and non-radiative Auger recombination can fully explain the pressure dependence of the threshold current where the threshold carrier density is approximately constant as a function of pressure. For the GaInNAs/GaAs devices we observe a large increase in threshold current with pressure. This we show is due to the interaction of the nitrogen level with the conduction band which gives rise to an increased conduction band effective mass resulting in an increase in threshold carrier density of ∼12% over 10 kbar. This large increase in n th increases the monomolecular, radiative and unusually, the Auger recombination current with pressure explaining the large increase in threshold current with pressure.

We report the variation of the modal refractive index at threshold with lasing wavelength in 1.3 μm InGaAsP, AlGaInAs and GaInNAs multiple quantum well lasers by measuring mode spectra under pressure up to 15 kbar. It is shown that the decrease of index with lasing wavelength is about 4% on average in the pressure range studied. We also find that the modal refractive index reduces with increasing injection current and is very sensitive to the injection current around laser threshold.

Generic InP foundry processes allow monolithic integration of active and passive elements into a common p-n doped layerstack. The passive loss can be greatly reduced by restricting the p-dopant to active regions. We report on a localized Zn-diffusion process based on MOVPE, which allows to reduce waveguide loss from 2 dB/cm to below 0.4 dB/cm. We confirm this value by fabrication of a 73 mm long spiral ring resonator, with a record quality factor of 1.2 million and an extinction ratio of 9.7 dB.

The threshold current has been measured as a function of pressure for a series of 1.5 μm InGaAs(P) lasers in which the position of the quantum wells (QWs) has been varied within the active region. Devices with the QWs positioned towards the p-doped cladding layer exhibit both a lower threshold current density and a reduced pressure dependence of the threshold current compared to devices with the QWs placed either symmetrically between the cladding layers or towards the n-doped cladding layer. Monte-Carlo simulations of the trajectories of Auger-generated hot carriers show that the escape probability of hot holes depends considerably more strongly on the QW position than is the case for hot electrons. The combination of the experimental measurements and Monte-Carlo simulations demonstrates the importance of Auger recombination processes which result in the production of hot holes.

Photonic integrated circuits (PICs) are considered as the way to make photonic systems or subsystems cheap and ubiquitous. PICs still are several orders of magnitude more expensive than their microelectronic counterparts, which has restricted their application to a few niche markets. Recently, a novel approach in photonic integration is emerging which will reduce the R&D and prototyping costs and the throughput time of PICs by more than an order of magnitude. It will bring the application of PICs that integrate complex and advanced photonic functionality on a single chip within reach for a large number of small and larger companies and initiate a breakthrough in the application of Photonic ICs. The paper explains the concept of generic photonic integration technology using the technology developed by the COBRA research institute of TU Eindhoven as an example, and it describes the current status and prospects of generic InP-based integration technology

In this contribution we present a control method and its experimental verification for a laser which wavelength is controlled using tunable arrayed waveguide gratings (AWGs). This device has been fabricated monolithically on a single InP chip. The 35 mm-long ring laser cavity contains two tunable intra-cavity AWGs and two strained InGaAs quantum well (QW) optical amplifiers with optical gain around 1.7 μm wavelength. The components are connected using passive waveguides. The tunable AWGs are controlled by electro-optic voltage-controlled phase modulators (PHMs) in the arms of the waveguide array. These PHMs need to be controlled individually to tune the laser to a specific wavelength. The layout of the laser is depicted in Fig. 1(a). It is identical to a quantum dot (QD) based laser reported in [1].

The design, fabrication and testing of 1550 nm DFB lasers with monolithically integrated electroabsorption modulators are reported. System performance of butterfly-packaged devices in 10 Gbit/s NRZ transmission over standard single mode fibre (SMF) with 17 ps/nm/km dispersion is included. Among the results are l0 Gbit/s transmission without the aid of optical amplifiers up to the theoretical limit of 50 km and up to 150 km using one optical booster amplifier.

We have designed and fabricated a monolithically integrated continuously tunable laser source for frequency domain optical coherence tomography (FD-OCT) in the 1.6 to 1.8µm wavelength region. The InP-based laser consists of two 8mm long quantum dot (QD) semiconductor optical amplifiers and two electro-optically (EO) tunable filters in a 43.5 mm long ring laser cavity. An 8mm long output amplifier is used to boost the output signal. A picture of the mask is given in Fig. 1a.

The effect of zinc diffusion on InGaAsP/InP single and multiple quantum well structures was studied by secondary ion mass spectrometry (sims), Auger electron spectroscopy (AES), capacitance‐voltage measurements, photoluminescence, and x‐ray diffraction. Significant interdiffusion of In and Ga is found. The structures are stale against annealing without the presence of zinc. Interdiffusion of As and P is negligible. In a multiple quantum well Zn diffusion at 500 °C causes In and Ga intermixing: The AES profiles have become flat. At higher diffusion temperatures an ordering is found such that now the Ga concentration is at a maximum in the original InP layers. This can be explained by minimization of the free energy, which is balanced by an increasse in mismatch strain energy. Photoluminescence shows the interdiffusion starts at temperatures above 420 °C. By the Zn diffusion the lattice parameter values of the InGaAsP and InP layers are changed and the average value is decreased, as was shown by x‐ray diffr...

Quantum well (QW) lasers are now being made routinely due to the remarkably well-developed OMVPE, MBE, and related epitaxial growth techniques. Because of the quantization, with consequent modification of the density of states of the injected electrons and holes in an extremely thin active layer, this type of lasers has been demonstrated to be superior to conventional double heterostructure (DH) lasers e.g. in threshold current, differential gain, characteristic temperature, maximum operating temperature, and power conversion efficiency. Recently, strained-layer structures with the QW layer composed of a semiconductor having a significantly different lattice parameter to the substrate material, have been introduced. The built-in strain resulting from the tetragonal distortion of the QW layer, splits the degeneracy of the heavy hole (HH) and light hole (LH) bands at the zone centre facilitating a new range of band structures for further enhanced device performance [1,2]. To date, strained-layer QW lasers showing enhanced performance over lattice matched QW and DH lasers emitting at visible (Al/sub x/Ga/sub y/ln/sub 1-x-y/P/GaAs), near infrared (AI/sub xGa/sub y/ln/sub 1-x-y/As/GaAs, employing AlGaAs or InGaP cladding layers) and long wavelengths (ln/sub x/Ga1.,As,P,_,/lnP and AI,Ga/sub y/ln/sub 1-x-y/As/InP) have been reported. This paper reviews the present state of the art in lattice matched and strained-layer MQW lasers in the above mentioned materials systems.

The sign of the strain in a multiquantum well (MQW) active layer of an InGaAs/InP laser determines whether lasing occurs from the electron–heavy hole transition or from the electron‐light hole transition. Lasing from the electron‐light hole transition is reported to provide a much better performance than predicted by theory. It is concluded that this gives the best device performance, providing a higher differential gain, a lower threshold current, a record low linewidth enhancement factor of 1.5, and a K factor of 0.22 ns, potentially allowing a 3 dB modulation bandwidth of 40 GHz.

Waveguides and corner mirrors are fabricated in InGaAsP/lnP. Properly aligned mirrors have a loss of 0.8 dB per reflection. This result is obtained by improved waveguide and mirror quality (surface roughness). Measured additional losses that are due to misalignment agree well with calculated values when a simple transformation method is used.

High quality quantum well structures of InGaAsP (λ=1.55 μm)/InP were grown by low‐pressure organometallic vapor phase epitaxy on 0.2° and 2° misoriented (001) InP substrates. Multiple‐line 2 K photoluminescence emission was observed for the first time from thin quantum wells of InGaAsP grown on 0.2° misoriented substrates. The multiple‐line emission is interpreted to result from half‐monolayer well width variations within one well with lateral sizes larger than the excitonic radius. Quantum wells grown on substrates with 2° misorientation showed generally wider single‐line photoluminescence emission due to well width variations within one well with lateral sizes smaller than the excitonic radius. The studied well thicknesses ranged from ≊70 A down to ≊4 A, which showed emission as short as 905 nm (1.37 eV) corresponding to a spectral upshift of 514 meV. The very high quality of the quantum wells of InGaAsP is indicated by a 2 K photoluminescence linewidth of 8.8 meV for a ≊6 A well.

Photoluminescence excitation measurements were performed on GaxIn1−xAsyP1−y/InP single quantum wells. The results were analyzed with a k⋅p approach. Using the effective masses reported in the literature, the ratio of the discontinuities in the conduction and valence band is found to be 35:65. This is in good agreement with a ratio of 37:63, obtained directly from an observed transition involving free holes.