2013 - optiwaveoptiwave.jp/home/product/optiwave - 2013 new features jpn.pdf · new testimonials...

Optiwave Systems Inc.

www.optiwave.com

年内リリース予定の新機能のご紹介

2013


www.optiwave.com

1. What’s New in OptiBPM 12

1.1 新たに開発されたモード・ソルバー

　今年の夏にリリース予定のOptiBPM 12には、磁場に基いた有限差分アルゴリズム[1] と Implicitly Restarted Arnoldi 法[2]を用いて、斬新な完全ベクトルモード・ソルバーが搭載されます。　この新しいモード・ソルバーは、高次モードをより高精度に求めることができます。弊社の従来開発したADI法モード・ソルバーより、精度が18倍も上がったことがファイバ・モードの理論値との比較で証明され、見つかった高次モードの信憑性もより高くなります。　この新しいモード・ソルバーのもう一つの特徴は、モードを求める際に中間結果が下図のように表示することができます。導波路・ファイバデバイスの研究開発の発展がより一層期待できます。

フォトニクス結晶のモード解析図（中間結果も）

[1] P. Lüsse, P. Stuwe, J. Schule, H-G Unger, “Analysis of Vector Mode Fields in Optical

Waveguides by a New Finite Difference Method”, Journal of Lightwave Technology, 12(3),

p487 – 493 (1994)

[2] R.B. Lehoucq, D.C. Sorensen, C. Yang, “ARPACK Users Guide, Solution of Large-Scale

Eigenvalue Problems with Implicitly Restarted Arnoldi Methods”, SIAM, Philadelphia, 1998.

1.2 64 bit シミュレーション　OptiBPMの中の一部プログラムが64bit対応になり、従来は32bitのメモリ制限のため、困難だった大規模なシミュレーションにも対応可能となります。同時に、今回のリリースでマルチCPU／マルチスレッドにも対応可能となります。


www.optiwave.com

2. What’s New in OptiFDTD 11.2

64-Bitの場合のシミュレーション動画作成　OptiFDTD 11.2は、今年の夏にリリース予定です。OptiFDTD 64-bitシミュレーションを行う場合、指定された観察面にシミュレーション動画が録画可能となります。光の伝搬画像がムービとして記録され、シミュレーション完了後、メディアプレイヤで再生されることができます。　この新機能によって、光フィールドの伝搬の様子が容易に再生・確認され、フォトニクス素子の開発を著しく促進することが期待されます。

下図は、リング共振器構造の導波路にパルス光が伝搬している様子をメディアプレイヤで再生しているイメージです。


www.optiwave.com

3. What’s New in OptiSystem 12

OptiSystem12は今年の6月ごろリリースする予定です。次のような新機能が追加されます。

・新しい送信機、受信機、エンドツーエンドの16-QAM／DP-16-QAM／DP-QPSKコヒーレント光通信システムのためのDSP素子を追加・新しい可視化素子が追加され、Dual Port可視化素子は離れた2つのバイナリ／光／電気信号端子に対して同時に波形解析を実現・新しい信号表示ビュアが追加され、すべての素子の出力端から出た実数・複素数のデータ行列を保存・表示することが可能・測定屈折率分布型マルチモードファイバ（Measured-Index Multimode Fiber）素子の機能を強化し、アルファー乗の分布型にも対応可能・OptiSystemのFileメニューから直接サンプル・プロジェクトにアクセス可能・レポート・タブ画面ではより大きい画面の設定が可能

3.1 新しいライブラリ素子

光送信機: 16-QAM, DP-16-QAM

• 二つの新しい素子 (16-QAM, DP-16-QAM) が光送信機ライブラリに追加されました。これによって、16-QAMおよび二重偏波16-QAMの変調リンクをよりすばやくセットアップしてシミュレーションすることができます。

光受信機: Coherent 16-QAM, Coherent DP-16-QAM

• 二つの新しい素子(Coherent 16-QAM, Coherent DP-16-QAM) が光受信機ライブラリに追加さ

れました。これによって、16-QAMおよび二重偏波16-QAMの変調リンクをよりすばやくセット

アップしてシミュレーションすることができます。

デジタル信号処理機: Viterbi-Viterbi feed forward phase recovery, DSP for DP-QPSK; DSP

for DP-16-QAM

• 二つの新しい素子(DSP for DP-QPSK, DSP for DP-16-QAM) が光受信機ライブラリに追加さ

れました。Viterbi-Viterbi feed forward phase recovery素子（単一ポートとデュアル

ポート）と同時に使用して、DP-QPSKとDP-16-QAMコヒーレント通信システムのエンドツーエ

ンドのシグナル変調およびBERの復元に役立ちます。• DSP for DP-QPSK素子には次の機能を含みます。

１．2ビット・ダウンサンプリング

２．分散補償素子

３．定包絡線信号用アルゴリズム（Constant Modulus Algorithm）を用いた偏光分波器

４．Viterbi-Viterbiフィードワード・アルゴリズムを用いた二重偏波キャリア位相評価器

Fig 1: 16-QAM constellation diagram


www.optiwave.com

• DSP for DP-16-QAM素子には次の機能を含みます。

１．2ビット・ダウンサンプリング

２．分散補償素子

３．RDE（Radius Directed Equalization）を用いた偏光分波器

４．Decision Directed Carrier Phase Recoveryを用いたキャリア位相評価器 Fig 2: DSP for DP-16-QAM

可視化ツール: 新しいDual Port素子

• 6つの新しい可視化ツール素子 (Dual Port Binary Sequence Visualizer, Dual Port M-ary Sequence Visualizer, Dual Port OTD Visualizer, Dual Port OSA, Dual Port Oscilloscope, and

Dual Port RF Spectrum Analyzer)が追加されます。離れた2つのポートに対して同時に比較分析を行い、より高精度な波形解析（バイナリ／M値／電気／光信号）を行うことができます。

Fig 3: Dual Port OSA Visualizer


www.optiwave.com

可視化ツール: 新しい “View signal” 素子

• 新しいシグナルの可視化ツール（View Signal Visualizer）が追加されます。これによって、OptiSystemが扱うすべてのタイプのシグナルをサンプリングしたデータ（実数・複素数）にアクセスすることができます。素子の出力ポートから収集した生データを画面に表示し、その全部あるいは一部をテキストまたはExcelフォーマットに保存できます。

Fig 4: View Signal Visualizer


www.optiwave.com

3.2 ライブラリ素子の機能を強化

Measured-Index Multimode Fiber 素子: アルファー乗の屈折率分布型ファイバにも対応可能

• 既存のMeasured-Index Multimode fiber素子の機能をさらに強化しました。アルファー乗の屈折率分布プロファイル、屈折率比、ピーク屈折率とクラッド屈折率を定義可能となります。

Fig 5: Measured-Index Multimode Fiber – New alpha profile parameters


www.optiwave.com

What’s New in OptiSPICE 4.0

OptiSPICE4.0は今年の6月ごろにリリースされる予定です。新しい可視化ツールにより、プローブからの電気シグナルまたは光シグナルを表示あるいは重ねて表示することが可能となります。その他に、新しい応用例も追加され、より詳細に設定されたホトダイオード（PD）の過渡モデルや、トランス・インピーダンス・アンプ（TIA）を含んだ集積光回路の例が含まれています。

4.1 新機能

OptiSPICE可視化ツール

• 従来のように、OptiSystemの可視化ツールを頼らず、直接にOptiSPICEで解析結果（波形）を見ることができます。

• 電気信号（電圧／電流）と光信号（振幅／位相）を単独でまたは複数で表示できます。

• スペクトラムのような高度な信号解析は、一つのオプションとして従来通りOptiSystemの可視化ツールを選択できます。

4.2 新しい応用例

ホトダイオード受信機の過渡モデル

• 既存のホトダイオード受信機の設計機能が強化され、より高度な過渡解析を行えるようになります。これにより、OptiSystemとの連動解析して高速なマイクロ波フォトニクスの研究に適用できます。

TIA モデル

• 新しいトランス・インピーダンス・アンプ（TIA）がサンプル例に追加され、受信機モデルの設計解析をより詳細に行えます。


www.optiwave.com

New Testimonials

2013


www.optiwave.com

On-Line Graduate Course on Simulation of

Optical Communication Systems with OptiSystem

Preparation of highly qualified personnel to drive the optical communications industry and spur

innovation requires training adapted to that industry’s requirements. In Canada, the Next

Generation Optical Networks (NGON) consortia was created at Queen’s University, Université

Laval and McGill University to provide graduate students with targeted training with industrial

input and participation. One outcome was the creation of a common graduate course on the

simulation of optical communications systems, first offered during the winter semester 2012.

Figure 1: Prof. LaRochelle (U. Laval) and graduate students B. Filon,

L. Gagné-Godbout and C. Jin (clockwise) discussing an simulation assignment on OptiSystem.

The thirteen week course was given on-line using Elluminate, an environment

that allows the instructor to share desktop applications and demonstrate simulation

tools. Students were able to participate by asking questions verbally or using a chat

window, as well as having access to archived video of the three hour lectures.

Practical training took the form of six assignments involving numerical simulations of

devices or systems. Some aspects of the assignments required students to write their

own code Matlab, while other aspects were based on the use of the OptiSystem

simulation package generously provided to NGON by Optiwave Systems Inc. The

detailed course content is presented below in Table 1. The course culminated with a

system simulation project that involved the design and optimization of a 2400 km link.

Students were able to identify factors that deterministically limit the system


www.optiwave.com

performance and to make compromises in order to achieve the optimum

performance. Students presented their solution to their colleagues during the last

session. This course was evaluated as a regular graduate course and students received

credit for a one-term course towards their degree requirements.

Table 1 : On-line graduate course content

Week Topics

1 Optical communication system overview and introduction to system simulation and

digital representation of signal and noise for system simulations.

2 Mathematical modeling of noise (simulation of random Poisson and Weiner processes,

electrical and optical noise) in the context of amplified WDM transmissions.

3-4 Description of semiconductor lasers using deterministic and stochastic rate equations

and their implementations for system simulations and laser performance assessment.

5-6 Mathematical models of optical modulators for amplitude and/or phase modulation

formats and their implementations for system simulations.

7-8 Linear and nonlinear propagation equations in optical fibers in their numerical solution for

system simulations taking into account dispersion and third order nonlinearities.

9 Properties of optical filters (integrated waveguide filters, arrayed-waveguide-gratings,

fiber gratings) and calculation of their transfer function for system simulations.

10 Operating principle of EDF and numerical tools for amplifier response simulations in

optical communication links including optical noise and dynamic response calculations.

11 Calculation of system performance at the receiver for various modulation formats (BER,

Q-factor, OSNR sensitivity) with respect to system parameters (dispersion, nonlinearity).

12 Forward error correction (encoding/ decoding/ implementations) and impact of coding on

system performance.

13 Project presentation on the design of an optical communication link.

Instructors found the OptiSystem software to be an efficient teaching tool that helped

to understand the various trade-offs involved when designing an optical

communication link. Its comprehensive design suite helped students bridge the gap

between the understanding of the physical models and their mathematical

representations, and the impact of the different parameters on system performance.

The software enabled students to experiment with optical link and network design in

a flexible manner. Indeed, OptiSystem allows integration of Matlab code to support

co-simulation in a fast and easy manner. Figure 2 below shows such an optical

communication link project. Graduate student Lin Dong considers the ability of

OptiSystem to connect to Matlab a very helpful feature and she said: “The interesting

thing about OptiSystem is that if you need to create a function that is not provided in

the simulator, it is easy to implement it in Matlab and then import it to OptiSystem”.

Students found the optical spectrum analyzer and time domain visualizers tools very

helpful to help them build their simulation. Furthermore, OptiSystem provides a


www.optiwave.com

hierarchically organized library of components and has a generous supply of examples

that helped the students get started. Xiaoyu Gong, a student who was taught about

using the simulator during this course describes his experience: “OptiSystem is very

useful in learning about optical communications. All kinds of optical links can be easily

built and tested. The detailed and well organized tutorials are really impressive. The

Matlab library makes the simulator an even more flexible and powerful tool”.

Figure 2: Simulation of an optical communication link using Optisystem

This graduate course contributed to developing student expertise by hands-on

training in numerical simulations, interpersonal skills through networking with

colleagues from other institutions, and leadership and planning in executing the

projects. The exposure to Matlab provided an in-depth, often component level,

simulation environment where models could be tweaked to observe the effect on

output predictions. The OptiSystem environment offers a comprehensive platform for

elaborate simulation setups, with the possibility of incorporating component-level

simulations from Matlab. Exposure to the ecosystem of numerical simulation tools

provided these students with skills that could be immediately applied on their

integration into industrial research and development for demanding, state-of-the-art

optical networks.

of 4

Using OptiSystem to Investigate Electronic Dispersion

Pre‐Compensation for a Directly Modulated Laser

Abdullah S. Karar and John C. Cartledge

Queen’s University

Directly modulated lasers (DMLs) provide a low cost solution for moderate reach systems due to their small footprint, low power dissipation and high output optical power. However 10 Gb/s on‐off keying DMLs are limited by an inherent modulation of the optical phase that accompanies the desired modulation of the optical intensity. This phase modulation1 limits the transmission reach to below 20 km for standard single‐mode fiber due to chromatic dispersion. Dispersion causes the transmitted optical pulses to spread out in time and interfere with each other. In conventional approaches, the dispersion is mitigated optically using dispersion compensating fiber or dispersion compensating fiber Bragg gratings along the link. Recently, a fundamentally different approach has been developed to mitigate dispersion using digital signal processing (DSP) implemented by an application specific integrated circuit (ASIC). At a DSP‐enabled transmitter, an optical signal that is pre‐compensated for dispersion can be generated using a high speed digital‐to‐analog converter (DAC) and an electrical‐to‐optical converter (e.g., external modulator or DML). The primary objective of this approach, as presented here, is to dramatically enhance the reach of DML based systems through precise control of the drive current and hence the modulated optical signal. A schematic of the pre‐compensating transmitter is shown in Fig. 1. The LUT entries are pre‐calculated using offline processing for a specific target distance. The generated digital samples are sent to a 21.418‐GSa/s DAC with 6‐bit resolution. The analog output of the DAC is then amplified and applied to a distributed feedback DML.

Fig. 1. Schematic of an electronic dispersion pre‐compensating DML transmitter. LUT: look‐up table; DSP: digital signal processing; DAC: digital‐to‐analog converter; DML: directly modulated laser.

One of the main challenges in the modelling and simulation aspects of such systems is the need for a comprehensive simulation environment which allows the integration of custom electronic components and advanced DSP algorithms with a fully featured application for optical transmission systems. OptiSystem was instrumental to the success of this research through offering the ability to interface with MATLAB. In MATLAB, custom designed DSP algorithms with look‐up tables followed by DAC emulation was possible, allowing for precise control over the drive current to the DML. A schematic diagram illustrating the various system components is shown in Fig. 2.

1 The chirp Δν(t) is related to the phase modulation φ(t) by ∆ .

of 4

Fig. 2. System simulation set‐up for electronic pre‐compensation using a DML. RF: radio frequency; DSP: digital signal processing; DAC: digital‐to‐analog converter; DML: directly modulated laser; SMF: single mode fiber; AWGN: additive white Gaussian noise; OBPF: optical band pass filter; ELPF: electrical low pass filter; BER: bit error ratio.

The incoming binary data is processed through a look‐up table, which is optimized for electronic dispersion pre‐compensation, as part of the DSP. The entries of the LUT in Fig. 1 are determined based on the effects of the DML adiabatic and transient chirp on pulse propagation, the nonlinear mapping between the input current and the output optical power, and the bandwidth of the DML package. A DAC operating at 2 samples per bit converts the digital samples at the output of the look‐up table to an analog current waveform driving the DML. The DSP and DAC combination were implemented in MATLAB, while the data generation, transmission system, receiver and bit error ratio (BER) calculation were performed in OptiSystem.

To accurately compare the simulated and measured results the DML rate equation parameters must be extracted. OptiSystem offers the ability to extract these parameters based on the measured small signal intensity modulation (IM) response of the laser. As such, the laser intrinsic large signal modulation dynamics were fully captured and the extrinsic electrical parasitic resulting from the laser package accounted for. Furthermore, the measured IM response of the different electrical and optical components such as the receiver optical band‐pass filter and electrical low‐pass filter were included using OptiSystem’s measured optical and electrical filters, respectively. The simulated and measured eye diagrams of the transmitted and received signal for the target distances of 202 km is shown in Fig. 3. Both simulated and measured eye diagrams exhibit significant similarity and indicate a remarkable eye opening after 202 km allowing for a 10 fold increase in the transmission reach of a DML.

The dependence of the measured BER on the OSNR (0.1 nm noise bandwidth) for back‐to‐back and 202 km transmission with an 11‐bit current LUT is shown in Fig. 4. A forward error correction (FEC) coding limit of BER = 3.8×10‐3 is assumed. For comparison, the back‐to‐back performance was evaluated by driving the laser with a raised‐cosine pulse train (roll‐off factor of 1.0) and a current swing between 1.18 Ith and 3.55 Ith where Ith denotes the threshold current.

of 4

The results indicate that using a single 11‐bit current LUT, EDC with a DML at 10.709‐Gb/s can reach a transmission distance of 202 km with a required OSNR of 18.6 dB. This is a remarkable improvement given the dispersion limit for this particular DML is below 20 km. Implementing the back‐calculation as an 11‐bit LUT results in a 1.3 dB OSNR penalty at the FEC limit of BER = 3.8×10‐3.

Fig. 3: Electrical eye diagrams for EDC at a target distance of 202 km: (a) simulation (b) measurement of the pre‐compensated signal at the output of the DML. (c) simulation (d) measurement of the received signal after fiber link. (Time span 300 ps).

Fig. 4. The dependence of the measured BER on the OSNR (0.1 nm noise bandwidth) for the back‐to‐back case and 202 km transmission with an 11‐bit current LUT. (FEC limit BER = 3.8×10‐3 dashed line).

of 4

Journal and conference papers that describe this approach to dispersion compensation more fully are given below.

[1] A. S. Karar, M. Yañez, Y. Jiang J. C. Cartledge, J. Harley and K. Roberts, “Electronic Dispersion Pre‐compensation for 10.709‐Gb/s using a Look‐Up Table and a Directly Modulated Laser,” Optics Express, vol. 19, no. 26, pp. B81‐B89, 2011.

[2] A. S. Karar, J. C. Cartledge, J. Harley and K. Roberts, “Electronic Pre‐Compensation for a 10.7‐Gb/s System Employing a Directly Modulated Laser,” IEEE/OSA J. Lightwave Technol., vol. 29, no. 13, pp. 2069‐2076, 2011.

[3] J. C. Cartledge, Y. Jiang, A. S. Karar, J. Harley and K. Roberts, “Arbitrary Waveform Generation for Pre‐compensation in Optical Fiber Communication Systems,” Invited Paper, Optics Communications, vol. 284, no. 15, pp. 3711‐3717, 2011.

[4] A. S. Karar, M. Yañez, Y. Jiang J. C. Cartledge, J. Harley and K. Roberts, “Electronic Dispersion Pre‐compensation using a Directly Modulated Laser at 10.7‐Gb/s,” European Conference on Optical Communication, Geneva, Switzerland, 18‐22 September 2011.

[5] A. S. Karar, J. C. Cartledge, J. Harley and K. Roberts, “Reducing the Complexity of Electronic Pre‐compensation for the Nonlinear Distortions in a Directly Modulated Laser,” Signal Processing in Photonics Communications, Toronto, Canada, 12‐16 June 2011.

[6] A. S. Karar, Y. Jiang, J. C. Cartledge, J. Harley, D. J. Krause and K. Roberts, “Electronic Precompensation of Nonlinear Distortion in a 10 Gb/s 4‐ary ASK Directly Modulated Laser,” European Conference on Optical Communication, Turin, Italy, 19‐23 September 2010.

2013 - optiwaveoptiwave.jp/home/product/optiwave - 2013 new features jpn.pdf · new testimonials...

Documents