in optisystem older version i did it by giving by using time delay unit ..by manually calculating the time delay with respect to pi/2  phase..may this idea be helpful for you

I think a phase shift component can help you. Please see the attached picture.

Hi love kumar, I appreciate your answer, but I was looking for the mathematics how to calculate the required delay as you have mentioned. Thank you.

Regards,

Dhiman

Dear Yunhao, Will you please elaborate how an additional phase shifter will help to do so. is it possible to adjust it by using the MZM parameters e.g. bias voltage.  Thanks

Regards,

Dhiman

In principle, the 90 degree phase shift can be realized by dual-parallel MZM with Vπ /2 bias voltage difference between upper and lower branch. In simulation, u can use the DP-MZM or set the two parallel optical paths like a DP-MZM structure with a 90 degree phase shift in one path.

Thank you Sir, can we do the same using only one dual drive LN-MZM, how the phase shift is related to the bias voltage.

Regards,

same problem...

To a good approximation if we write B = pi/2 * (Vin/Vbias)

then Transfer function of MZM is approx

output optical = input optical * 1/sqrt(IL) * cos (B)

if u r applying RF to the MZM then write

Vin = Vbias + Vrf(t)

so B is now = Bbias + Brf(t)

in absence of RF

B = Bbias = (pi/2) (Vbias/Vpi)

and output optical = input optical * 1/sqrt(IL) * cos (B)

so phase-shift optical ~ B