MZM Bias voltage for getting CSR close to 0dB.

[Gokul Boro .]

Hi all,

I have been trying to analyse the performance of a system. For that, I need to find an optimum Carrer to Sideband Ratio for better system performance. The problems are—

1) How do I measure CSR in Optisystem?
2) How do I adjust the bias voltages in Lithium-Niobate MZM, so that I can get CSR close to 0dB? Lithium-Niobate has four bias voltages.
Switching bias voltage(does it mean Vpi?),Switching RF voltage, Bias voltage 1 and Bias voltage 2. How do I set these parameters?
MZM is to be operated at 0.5Vpi and in Push-Pull Pattern.

Is there any example available for this CSR adjustment?

Also please help me in this too https://optiwave.com/forums/topic/carrier-to-sideband-power-ratio-cspr/

[Damian Marek]

Gokul,

1) Use an optical spectrum analyzer which you can investigate to calculate the CSR.
2) The technical background explains these bias voltages in greater detail, but I find setting V switching bias and Vrf separately to be confusing so I always set them to the same value. When they are the same value they will act as a Vpi. Vbias1 and Vbias2 I think are self evident, they are the DC voltages applied to port 1 and port 2 respectively. Note: You can set your own Vbias by adding a DC value to your input electrical signal if you would like.

For 0.5Vpi operating point you would want port 1 to be biased at Vpi/4 and port 2 biased at -Vpi/4. The electrical signal that is connected to the second port should also be sent through an electrical amplifier with -1 Gain so that the signal is reversed.

Regards

[Gokul Boro .]

Thank you Damian.
Can I use WDM analyzer to measure the Sideband power? I was trying to do so but couldnot measure the sideband power separately. I tried setting the parameters lower and upper frequency limit of the WDM analyzer such that only the sideband comes withing that limit. The figure of the spectrum is attached. Resoultion bandwidth of WDM analyzerwas set to be 0.05.

Thank you

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