RF Reference Signal Transmission System　WSL-1 / WRM-2

http://www.graviton.co.jp ～ Ultra-low Jitter of 1ps rms or less ～ RF Reference Signal Transmission System For J-PARC Linac TT L WSL-1 WRM-2 パルス信 （Laser Source） （O/E Receiver） 号 光 Installation record: KEK and others リン ク ■Overview J-PARC (Japan Proton Accelerator シ In J - PARC proton linac, 972 MHz RF reference signal is distribut- Research Complex) ス ed to Klystron driving stations by optical fiber transmission. In the accelerated electric field (972 MHz), the phase deviation J-PARC consists of multiple proton accelera- テ should be ± 1 ° or less and the amplitude fluctuation should be ± tors and experimental facilities for a wide ム 1% or less. In 300 m of the linac, 60 Klystron driving stations are range of research purpose including proton installed, so the RF reference signal requires super high stability. particle and nuclear physics, materials and The phase deviation from station to station should be ± 0.3 ° or life science, and nuclear technology. less (about ± 0.9 ps) at 972 MHz). The optical components (E/O Module and O/E Module) for the transmission devices, which Graviton has developed, provide excellent temperature characteristics and ultra-low jitter, in addition to clearing such a strict phase deviation requirement. 【Key Feature】 ●A Butterfly DFB Laser Diode with built-in Peltier is mounted WSL-1 Transmitter (1 output channel ) High Energy Accelerator Research Organization W430mm、D260、H44 (EIA-1U） WSL-16 Transmitter（ 出力16ch） ●16 output channel version of WSL-1（ by branch coupler ) W430mm、D360、H88 (EIA-2U） 【Key Feature】 ●WRM-2（3Gbps O/E Receiver Module） WRM-2 Receiver O/E conversion by digitalizing with a transimedance amplifier and a limiting amplifier 15 Peltier can be optionally mounted, 42mm 35 contact Graviton for details. This image is provided by KEK. ～ 26th anniversary ～ KEK-JAPAN High Energy Accelerator Research_Organization Ultra-low Jitter RF Reference Signal OOppttiiccaall lliinnkk System

WSL-1(Laser Source) / WRM-2(O/E Receiver) ■WSL-1 (Wavelength Stabilized Laser Source)　 ■Measurements of jitter when modulated with 960MHz WSL-1 is a Laser source with wave- length stabilization and modulation function. A DFB Laser diode with Peltier is mounted: Direct modulation by Laser drive current modulation is employed: The internal circuit of the device shapes waveform into square wave: Rising of the jitter from the non-inverting output terminal when inputting 960MHz modulation light RMS jitter: 860fs Ultra-low jitter is provided. (including the measuring system jitter of 746fs) ■WRM-2 (O/E Receiver Module)　 WRM-2 is the O/E Receiver module, which mounts a transimpedance amplifier and a limiting amplifier to digitalize. ■Using a combination of WRM-2 and WSL-1 provides ultra-low jitter of 1ps Falling of the jitter from the non-inverting output terminal when inputting 960MHz modulation light RMS jitter: 877fs or less (See the example). (including the measuring system jitter of 741fs) ■ WSL-1 Specification Output connector of modulation Item Description Remark SMA receptacle on the front panelmonitor signal Model name WSL-1 Wavelength stabilized Laser source with Double Peltier system by controlling the feed- Function modulation function back from thermistor and Peltier built in the LDTemperature controlling of Laser Butterfly package DFB Laser module with module and the temperature of the entire LD Light emitting element Peltier module Wavelength 1550nm Setting temperature to Laser 30 ℃ Emission spectrum bandwidth 10MHz Controllable ambience temperature 20 ℃ to 40 ℃ Wavelength stability ±0.1nm or less Supply voltage and current AV100V, Max 500mA Number of emitting device 1 430mm(W)x260mm(D)x44mm(H) Excluding protruding Dimensions Number of optical output channel 1 channel for EIA -1U parts, such as Optical output level 0dBm Compatible optical fiber Single-mode quartz optical fiber ■ WSL-2 Specification Optical output connector FC receptacle on the front panel Shaping waveform to Item Description Remark Direct modulation by Laser drive current square wave by the Model name WRM-2 Light intensity modulation modulation internal circuit of the Function 3Gbps O/E Receiver module device Light-receiving element InGaAs PIN photodiode Modulation rise time 200ps or less (10%-90%) Rated wavelength of receiving light 1550nm Frequency modulation bandwidth 100kHz to 2GHz Wavelength range of receiving light 1000nm to 1650nm 800mVp-p(Recommended) Level of receiving light +1dBm to -20dBm -3dBm as standard Modulation input level (100mVp-p to 1Vp-p) Number of light-receiving element 1 Modulation input impedance 50Ω　０V(Terminator) , AC coupling Compatible optical fiber Single-mode quartz optical fiber Modulation input connector SMA receptacle on the front panel Optical input connector Pigtail connector with FC plug, 1m length Light intensity increases at a falling of the Digitalizing by a transimpedance amplifier and a Polarity of modulation signal voltage of the modulation input signal and it O/E conversion limiting amplifier decreases at a rising of the voltage. Extinction ratio of optical 7dB or greater (modulated by Pseudo Random Convertible frequency bandwidth 100kHz to 2GHz Dduty cycle : 50% modulation Binary Sequence (PRBS) with 2.5Gbps) Signal Output level 400mVp-p 5Ωtermination Controlling the drive current of the LD by Rise time of output signal 200ps or less (10% to 90%) Laser output stabilization feeding back the current monitored from the Conversion input impedance 50Ω　０V(Terminator) , AC coupling The output terminal to send the monitor signal Number of channel to output Two outputs are in If not used, use 50 Ω 2 channels to external device, after shaping the waveform converted signal opposite phase Modulated signal monitoring terminator to of the input signal from the modulation input Output connector of conversion terminate. SMB type receptacle terminal. signal Polarity of modulation signal Opposite phase to modulation input signal Supply voltage +5V Output impedance of modulation Supply current 150mA or less 50Ω , AC coupling monitor signal Excluding protruding parts, such as Dimensions of OE module 42mm(W)x35mm(D)x15mm(H) Output level of modulation 400mVp-p or greater screws and monitor signal connectors, etc. Contact us Tel. +81 (42) 966-0816 Fax. +81 (42) 966-0817 Email: info@graviton.co.jp 15-5 Kawara-machi, Iruma-shi, Saitama, 350-0008, Japan http : //www.graviton.co.jp GRAVITON is the registered trademark of Graviton Inc. No. WSL_E171030-01