Query: High power laser direct modulation

title: Study on the direct modulation characteristics of high power semiconductor laser
abstract: The direct modulation of high power semiconductor laser driver that is composed of the current modulation circuit and the over current protection circuit is introduced, two direct modulation circuits with different modulation output current amplitude are designed and the direct modulation of characteristics is analyzed, providing the output current waveform of the direct modulation of high power semiconductor laser. In this paper, a new modulation output current with a peak current of 9.5A is designed with bias current of 0.8A and the modulation current bandwidth of 2.56MHz. The width of the modulation current pulse keeps stable after widening. When the input signal is voltage pulse with uniform pulse width, it can output current pulse with uniform pulse width. And the modulation output current with a peak current of 9.5A is designed with bias current of 0.8A and the modulation current bandwidth of 5MHz. We have a theoretical study on the dynamic characteristics of direct modulation of semiconductor laser. We also have done some experiments on the basis of the simulation, the experimental results show that the output pulse laser intensity and the pulse laser modulation signal width change with changing the width of the pulse, and the actual modulated output pulse laser has a certain time delay with respect to the modulated signal.

title: 95 oC uncooled and high power 25 Gbps direct modulation of InGaAlAs ridge waveguide DFB laser
abstract: 95oC, 25 Gbps direct modulation of a high power (15mW) 1.3 um InGaAIAs DFB laser is developed for the first time. The device will be a key for 4 channel CWDM uncooled light sources used in the lower power consumption 100 GbE subsystems.

title: 1.3 mm p Modulation Doped InGaAs/GaAs Quantum Dot Lasers with High Speed Direct Modulation Rate and Strong Optical Feedback Resistance
abstract: Aiming to realize high speed optical transmitters for isolator free telecommunication systems, 1.3 mm p modulation doped InGaAs/GaAs quantum dot (QD) lasers with a 400 mm long cavity have been reported. Compared with the un doped QD laser as a reference, the p doped QD laser emits at ground state, with an ultra low threshold current and a high maximum output power. The p doped QD laser also shows enhanced dynamic characteristics, with a 10 Gb/s large signal direct modulation rate and a 7.8 GHz 3dB bandwidth. In addition, the p doped QD laser exhibits a strong coherent optical feedback resistance, which might be beyond 9 dB.

title: Two electrode high power tapered laser with up to 40.5 W/A static modulation efficiency and 700 Mb/s direct modulation capability
abstract: We report a high modulation efficiency two electrode tapered laser with a record 0.81 W output optical modulation amplitude for 70 mA applied current swing under 700 Mb/s direct modulation. In addition the device shows a record 40.5 W/A static modulation efficiency.

title: High Speed Direct Modulation of a Heterogeneously Integrated InP/SOI DFB Laser
abstract: An integrated laser source to a silicon photonics circuit is an important requirement for optical interconnects. We present direct modulation of a heterogeneously integrated distributed feedback laser on and coupled to a silicon waveguide. We demonstrate a 28 Gb/s pseudo random bit sequence non return to zero data transmission over 2 km non zero dispersion shifted fiber with a 1 dB power penalty. Additionally, we show 40 Gb/s duobinary modulation generated using the bandwidth limitation of the laser for both back to back and fiber transmission configurations. Furthermore, we investigate the device performance for the pulse amplitude modulation (PAM 4) at 20 GBd for high speed short reach applications.

title: 4 Gbps direct modulation of 450 nm GaN laser for high speed visible light communication.
abstract: We demonstrate high speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high speed visible light communication setup. Record high 4 Gbps free space data transmission rate was achieved at room temperature.

title: Multi band power allocation in AMOOFDM high data rate NG PON downlink transmission direct modulation of linear laser
abstract: Multi band power allocation for NG PON downlink transmission is experimentally demonstrated when implementing AMOOFDM with direct modulation of a linear laser. Multi user power and bit allocation allows the users datarates to be balanced according to a target QoS.

title: Gbps direct modulation of 450 nm GaN laser for high speed visible light communication
abstract: We demonstrate high speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high speed visible light communication setup. Record high 4 Gbps free space data transmission rate was achieved at room temperature. (c)2015 Optical Society of America OCIS codes: (060.2605) Free space optical communication; (060.4080) Modulation; (140.7300) Visible lasers; (250.5960) Semiconductor lasers. References and links 1. S. Nakamura, M. Senoh, and T. Mukai, "P GaN/N InGaN/N GaN double heterostructure blue light emitting diodes,"  (1993) 2. S. Pimputkar, J. S. Speck, S. P. DenBaars, and S. Nakamura, "Prospects for LED lighting,"  (2009) 3. L. Grobe, A. Paraskevopoulos, J. Hilt, D. Schulz, F. Lassak, F. Hartlieb, C. Kottke, V. Jungnickel, and K. Langer, "High speed visible light communication systems,"  60 66 (2013) 4. J. D. McKendry, D. Massoubre, S. Zhang, B. R. Rae, R. P. Green, E. Gu, R. K. Henderson, A. E. Kelly, and M. D. Dawson, "Visible light communications using a CMOS controlled micro light emitting diode array,"  (2012) 5. S. Zhang, S. Watson, J. McKendry, D. Massoubre, A. Cogman, E. Gu, R. K. Henderson, A. E. Kelly, and M. D. Dawson, "1.5 Gbit/s multi channel visible light communications using CMOS controlled GaN based LEDs,"  1211 1216 (2013) 6. J. D. McKendry, R. P. Green, A. E. Kelly, Z. Gong, B. Guilhabert, D. Massoubre, E. Gu, and M. D. Dawson, "High speed visible light communications using individual pixels in a micro light emitting diode array,"  1346 1348 (2010) 7. S. Zhang, S. Watson, J. McKendry, D. Massoubre, A. Cogman, E. Gu, R. K. Henderson, A. E. Kelly, and M. D. Dawson, "1.5 Gbit/s multi channel visible light communications using CMOS controlled GaN based LEDs,"  1211 1216 (2013) 8. D. Tsonev, H. Chun, S. Rajbhandari, J. McKendry, S. Videv, E. Gu, M. Haji, S. Watson, A. E. Kelly, G. Faulkner, M. D. Dawson, H. Haas, and D. O'Brian, "3 Gb/s single LED OFDM based wireless VLC link using a gallium nitride mLED,"  (2014) 9. H. Chun, P. Manousiadis, S. Rajbhandari, D. A. Vithanage, G. Faulkner, D. Tsonev, J. D. McKendry, S. Videv, E. Xie, E. Gu, M. D. Dawson, H. Haas, G. A. Turnbull, I. D. Samuel, and D. O'Brian, "Visible light communication using a blue GaN mLED and fluorescent polymer color converter,"  (2014) 10. D. Tsonev, S. Videv, and H. Haas, "Towards a 100 Gb/s visible light wireless access network," Opt. Express 23(2) 1627 1637 (2015) 11. S. Watson, M. Tan, S. P. Najda, P. Perlin, M. Leszczynski, G. Targowski, S. Grzanka, and A. E. Kelly, "Visible light communications using a directly modulated 422 nm GaN laser diode," Opt. Lett. 38(19) 3792 3794 (2013) 12. K. A. Denault, M. Cantore, S. Nakamura, S. P. DenBaars, and R. Seshadri, "Efficient and stable laser driven white lighting," AIP Adv. 3(7) 072107 (2013) 13. J. E. Bowers, "High speed semiconductor laser design and performance," Solid State Electron. 30(1) 1 11 (1987) 14. L. A. Coldren, S. W. Corzine, and M. L. Mashanovitch, Diode Lasers and Photonic Integrated Circuits, 2nd ed. (Wiley Interscience, 2012)  2015; revised 23 May 2015; accepted 25 May 2015;  2015

title: Terahertz direct modulation techniques for high speed communication systems
abstract: Terahertz communication technology can provide abundant frequency resources, strong confidentiality, antijamming capability, communication tracking capability and the ability to achieve highspeed data transmissions and can serve as an important technical method for high speed communications in the future. Among these terahertz communication technologies, terahertz direct modulation technology is a key means to achieve low system complexity and power consumption. In this paper, a review and outlook of terahertz direct modulation technology are proposed from the aspects of high electron mobility transistor based terahertz direct modulation, parallelswitch terahertz direct modulation, diode based terahertz direct modulation, quantum cascade laser based terahertz direct modulation and new material based terahertz direct modulation. We hope through this paper that more readers can gain knowledge about the development and challenges of terahertz direct modulation technology for high speed communication systems, thus promoting the development of high speed terahertz communication technology based on direct modulation.

title: High power narrow linewidth Raman amplifier and its limitation
abstract: We investigated the limitations in output power generated by a high power narrow linewidth Raman fiber amplifier. The pump was produced by a kW level all fiber Yb doped amplifier emitting at 1060 nm, whose seed linewidth could be changed. The Raman seed was a narrow linewidth signal at 1110 nm co propagating with the laser at 1060 nm. The main Raman conversion occurred in the passive fiber at the amplifier output. We identified cross phase modulation (XPM) as a main reason for broadening of the Raman light by using different pump sources, which is a first limitation. An improved setup was limited at approximately 600 W of Stokes output power by a threshold like onset of a transverse mode instability. Since the instability was not observed without a Stokes seed and the temperatures of the active fiber with and without Stokes seed are equal, this constitutes the first direct observation of transverse mode instabilities (TMI) induced by SRS in a passive fiber.