The EOM driver is working. For the same modulation depth, it can drive a broadband EOM using less power.
==measurement and result==
I used PMC setup to test this EOM driver because its frequency range is only ~21 - 24 MHz, and the sideband for locking PMC is 21.5 MHz. So what I did:
From the schematic, the board is supposed to have 30V output from 0.15 V output (x200). In dBm that will be 20log(200)~ 23dBm. So It is roughly ok.
fig1: BB EOM with the driver. One of the unused output is for output mon.
fig2: Error signal from scanning the laser, with BB eom and the driver, measured at mixer out.
The board is definitely working and will benefit us, definitely for locking PMC. If we use a marconi to drive a BB EOM, the max output is 13dBm. The power is halved (one to the EOM, one to the mixer). That means ~ 10dBm to the EOM (we will probably split more some where for RFAM pickup, but we can do that on the line that goes to the mixer), so assuming we have ~ 10dBm for the EOM. With the board it will be ~ 10+18.5 dBm = 28.5dBm (~6V) . It should give modulation depth of 0.09, see psl:745, This might not be enough for locking the refcav( see,psl:929. where we have beta of 0.18), but we can add another RF amplifer, or use the board for PMC servo . I'll check what are the appropriate modulation depth for locking PMC and refcav.