Team Leader VPI Development Center Belarus Hi-Tech Park Chapajeva street 5, Office 111 220034 Minsk, Belarus

Our team is glad to announce creation of the VPIcomponentMaker™ Photonic Circuits - a new tool for a system-level modeling of large-scale photonic integrated circuits (PICs).

Being based on our old and well-established VPIcomponentMaker™ Active Photonics product, the VPIcomponentMaker™ Photonic Circuits remains one of the most convenient tools for modeling the full longitudinal and spectral dynamics of active photonics devices such as semiconductor lasers and optical amplifiers (SOAs). Frequency-dependent models for stimulated emission spectra allow accurate amplification of multi-wavelength signals anywhere in the gain spectrum, with carrier-dependent width and peak. The loss-coupling, nonlinearity time constants, MQW materials, multiple-phase shifts and logarithmic gain are included.

In addition, now the VPIcomponentMaker™ Photonic Circuits includes a family of passive PIC elements (such as directional, MMI and star couplers, microrings, waveguides and waveguide branches) modeled in terms of S-matrix approach and implements both, the frequency- and time-domain simulation modes. Accurate analytical models (coupled-mode theory, self-imaging MMI model, Fourier optics star coupler model) grant fast PIC design and optimization of design tolerances. Measured models allow to realistically model PICs with customized components. Flexible characterization of TE and TM guided modes allows investigation of birefringence, polarization coupling and dispersion effects.

Importantly, the detailed PICs modeling in the VPIcomponentMaker™ Photonic Circuits can be fully integrated (within a single simulation setup) with fiber-systems simulations in the VPItransmissionMaker™ Optical Systems, thus allowing to study performance of the modeled PICs for a rich set of advanced modulation formats (mQAM, DPSK, DQPSK, etc) or in a fiber-optics environment.

Examples of the VPIcomponentMaker™ Photonic Circuits applications can be found on the pages:

• AWG with Flattened Spectral Response
• Reconfigurable Power Splitter Based on 5x5 MMI Coupler
• Ring-loaded Mach-Zehnder Interferometer
• InP QPSK Vector Modulator

Time-and-frequency-domain modeling (TFDM) of hybrid photonic integrated circuits This work addresses the efficient modeling of hybrid large-scale photonic integrated circuits (PICs) comprising both, active and passive sub-elements. We describe a new modeling approach, the time-and-frequency-domain modeling (TFDM) that improves accuracy, memory requirements and simulation speed in comparison with traditional pure timedomain method. In TFDM, clusters of connected linear PIC elements are modeled in frequency domain, while interconnections between such clusters and non-passive PIC elements are modeled in the time domain. Behavioral models of the fundamental building blocks of PICs are presented and combined in several application examples showing the robustness of the entire modeling framework for PICs. Proc. of SPIE, Jan 2012. Detailed modeling of integrated IQ-transmitters for 100G+ applications We present techniques for modeling the physics and systems-level characteristics of integrated IQ-transmitters for 100G+ applications and emphasize important design aspects. Using time-and-frequency-domain modeling (TFDM) of Photonic Integrated Circuits (PIC), we present a detailed IQ-transmitter model based on the physics and setup of active and passive subcomponents. With this, we link characteristics of subcomponents (bending loss of waveguides, phase changes in MMI couplers, sweep-out time of EAMs) to systems-level characteristics of the integrated IQ-transmitter (extinction ratio, modulation bandwidth, chirp). Further, a behavioral transmitter model is introduced and utilized to assess electrical driving requirements (allowed jitter, noise, synchronization offset). Proc. of SPIE, Jan 2012. Hybrid Time-and-Frequency-Domain approach for modeling photonic integrated circuits Modern simulators of photonic integrated circuits (PICs) employ either frequency-domain or time-domain approaches for system-level modeling of PICs. We critically examine limitations of both approaches that obstruct their usage for simulations of large-scale PICs, and suggest an efficient hybrid alternative. Within this new approach clusters of connected linear PIC elements are modeled in frequency domain, while interconnections between such clusters and non-passive PIC elements are modeled in time domain. Proc. of NUSOD, Sep 2011. Comparison of XPM and XpolM-induced impairments in mixed 10G-100G transmission We reviewed the origin and impact of the cross polarization modulation (XpolM) effect. An analysis of the Manakov equation has been carried out in order to differentiate between XpolM and XPM effects. Based on this analysis, it has been argued that the impact of XpolM may have been overestimated so far. To verify this statement, the performance of a 112Gb/s DP-QPSK channel over 10Gb/s legacy system has been investigated with the help of numerical simulations. We showed that the impact of XpolM is smaller than the impact of XPM and intra-channel nonlinearities (iXPM, iFWM). Our presented results assessing the impact of the XpolM effect confirmed theoretical predictions that have been reported in. Finally, our investigations have shown that the impact of XpolM-induced distortion is reduced by PMD. Proc. of ICTON, Jun 2011. Efficient design of Photonic Integrated Circuits The exponentially growing number of components in complex large-scale Photonic Integrated Circuits (PICs) requires the necessity of photonic design tools with system-level abstraction. This work addresses the modeling of large-scale integrated PICs from a system-level perspective. Behavioral models of ring resonators, multimode interference devices, optical waveguides and other fundamental building blocks of PICs will be presented and combined to demonstrate several application examples of photonic circuit designs. Proc. of ICTON, Jun 2011. Design of complex large-scale photonic integrated circuits (PICs) based on ring-resonator structures The exponentially growing number of components in complex large-scale Photonic Integrated Circuits (PICs) requires the necessity of photonic design tools with system-level abstraction, which are efficient for designs enclosing hundreds of elements. Ring-resonators and derived structures represent one example for large-scale photonics integration. Their characteristics can be parameterized in the frequency-domain and described by scattering matrix (S-matrix) parameters. The S-matrix method allows time efficient numerical simulations, decreasing the simulation time by several orders of magnitude compared to time-domain approaches yielding a better modeling accuracy as the number of PIC elements increases. We present the modeling of optical waveguides within a sophisticated design environment using application examples that contain ring-resonators as fundamental structure. In the models, the two orthogonally polarized guided modes are characterized by their specific index and loss parameters. Systematic variation of circuit parameters, such as coupling factor or refractive index, allows a comfortable design, analysis and optimization of many types of complex integrated photonic structures. Proc. of SPIE, Jan 2011. Design of complex semiconductor integrated structures We present the benefits and limitations for designing complex optical semiconductor-based integrated structures by means of advanced numerical modeling. Multi-section tunable laser designs are presented and their tuning properties are analyzed for different architectures. We introduce a model of an integrated SOA with electroabsorption modulator. Its spectral properties are analyzed function of the parameters of the absorber section, showing the influence on the extinction ration of the generated signal. An InP-type Mach-Zehnder modulator is designed, illustrating the models of Kerr, Frank-Keldysh and QCSE effects. An example of a photo-detector demonstrates how dimensions and absorption parameters can be optimized to increase its detection bandwidth. Proc. of SPIE, Nov 2009. Coupled-resonator-induced reflection in photonic-crystal waveguide structures We study the resonant transmission of light in a coupled-resonator optical waveguide interacting with two nearly identical side cavities. We reveal and describe a novel effect of the coupled-resonator-induced reflection (CRIR) characterized by a very high and easily tunable quality factor of the reflection line, for the case of the inter-site coupling between the cavities and the waveguide. This effect differs sharply from the coupled-resonator-induced transparency (CRIT) – an all-optical analogue of the electromagnetically-induced transparency – which has recently been studied theoretically and experimentally for the structures based on microring resonators and photonic crystal cavities. Both CRIR and CRIT effects have the same physical origin which can be attributed to the Fano-Feshbach resonances in the systems exhibiting more than one resonance. We discuss the applicability of the novel CRIR effect to the control of the slow-light propagation and low-threshold all-optical switching. Opt. Express, Jul 2008. Photonic crystals with anomalous dispersion: Unconventional propagating modes in the photonic band gap We present an investigation of the optical properties of photonic crystals whose constituent materials exhibit anomalous dispersive behavior. In particular, the anomalous dispersion near resonances may lead to additional propagating modes in the gap of the undoped system for a localized region of wave-vector space. Such a system may be realized by infiltrating quantum dots in polymer suspensions into the pores of two-dimensional high-index photonic crystals. An evaluation of the absorption lengths associated with these unconventional modes and corresponding transmission calculations demonstrate that this effect can be observed in currently accessible structures. Phys. Rev. B, Jan 2008. Wannier-function based scattering-matrix formalism for photonic crystal circuitry A guided-mode scattering matrix approach to photonic crystal integrated devices, based on the expansion of the electromagnetic field in Wannier functions is presented and its applicability to large-scale photonic circuits is demonstrated. In particular, we design two components typically used in wavelength division multi/demultiplexing applications, namely, a directional coupler and a Mach–Zehnder interferometer, and we analyze the transmission spectra as a function of the coupler length and/or delay line length, respectively. These examples demonstrate that by cascading basic functional elements, large-scale circuits can be accurately described and efficiently designed with minimal numerical effort. J. Opt. Soc. Am. B, Jan 2008. Low-threshold bistability of slow light in photonic-crystal waveguides We analyze the resonant transmission of light through a photonic-crystal waveguide side coupled to a Kerr nonlinear cavity, and demonstrate how to design the structure geometry for achieving bistability and all-optical switching at ultralow powers in the slow-light regime. We show that the resonance quality factor in such structures scales inversely proportional to the group velocity of light at the resonant frequency and thus grows indefinitely in the slow-light regime. Accordingly, the power threshold required for all-optical switching in such structures scales as a square of the group velocity, rapidly vanishing in the slow-light regime. Opt. Express, Sep 2007. Periodic nanostrutures for photonics Periodic nanostructures in photonics facilitate a far-reaching control of light propagation and light–matter interaction. This article reviews the current status of this subject, including both recent progress and well-established results. The primary focus is on the basic physical principles and potential applications associated with the existence of Bragg scattering, photonic band structures, and engineered effective-medium properties in periodic dielectric and metallo-dielectric systems. In addition, we discuss advantages and limitations of various theoretical and numerical approaches as well as of those fabrication techniques that have specifically been developed for this field. Physics Reports, Mar 2007. Other publications highlights...