40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Entry  Wed Jul 20 11:58:45 2022, Paco, Summary, General, Jenne laser kaput? 
    Reply  Wed Jul 20 14:12:07 2022, Paco, Summary, General, Jenne laser kaput! 
       Reply  Wed Jul 20 15:58:52 2022, Koji, Summary, General, Jenne laser kaput! 
          Reply  Mon Jul 25 09:05:50 2022, Paco, Summary, General, Testing 950nm laser found in trash pile PXL_20220722_234600124.jpgPXL_20220722_234551918.jpg
             Reply  Fri Aug 5 17:03:31 2022, Yehonathan, Summary, General, Testing 950nm laser found in trash pile 20220805_164434.jpgLaserActuation_TF_Measurement.drawio.pdf
Message ID: 17064     Entry time: Fri Aug 5 17:03:31 2022     In reply to: 17030
Author: Yehonathan 
Type: Summary 
Category: General 
Subject: Testing 950nm laser found in trash pile 

I set out to test the actuation bandwidth of the 950nm laser. I hooked the laser to the output of the bias tee of PD testing setup. I connected the fiber coming out of the laser to the fiber port of 1611 REF PD.

The current source was connected to the DB9 input of the PD testing setup. I turned on the current source and set the current to 20mA. I measured with a fluke ~ 2V at the REF PD DC port.

I connected the AC port of the bias tee to the RF source of the network analyzer and the AC port of the REF PD to the B port of the network analyzer. Attachment 2 shows the setup.

I took a swept sine measurement (attachment) from 100kHz to 500MHz.

It seems like the bandwidth is ~ 1MHz which is weird considering the spec sheet says that the pulse rise time is 0.5ns. To make sure we are not limited by the bandwidth of the cables I looped the source and the input of the network analyzer using the cables used for the previous measurement and observed that the bandwidth is a few 100s of MHz.

Attachment 1: 20220805_164434.jpg  902 kB  Uploaded Fri Aug 5 18:03:38 2022  | Hide | Hide all
20220805_164434.jpg
Attachment 2: LaserActuation_TF_Measurement.drawio.pdf  43 kB  Uploaded Fri Aug 5 23:58:13 2022  | Hide | Hide all
LaserActuation_TF_Measurement.drawio.pdf
ELOG V3.1.3-