Hello,
If you notice the equation expressed for the o/p of a Lithium Niobate MZM in the OptiSystem Component Library file which you can find in ‘Documentation’ sub-folder of OptiSystem folder, it is expressed in terms of the i/p optical field, insertion loss, electric voltages given onto the two arms of the Lithium Niobate MZM, DC bias voltages (Vbias1 and Vbias2), switching modulation (VpiRF) and switching bias (VpiDC) voltages. As Sir Sethi mentioned in the previous post, the electric voltages applied to the two arms result in a change of refractive indices in the two arms of the MZM.
The o/p optical field when expanded results in a expression containing cosine of cosine terms which can be expressed in terms of Bessel functions. Theoretically the o/p optical field contains infinite terms-an optical component at the same frequency as the i/p optical component and components at frequencies offset from the i/p optical component. Thus, if the frequency of sinusoidal is fs and that of the optical i/p is fo, the o/p optical field will contain components at frequencies, fo, (fo + n*fs), (fo – n*fs) where n = 1, 2, 3, …
* As far the properties are concerned, VpiDC and VpiRF are usually the same and set to Vpi.
* The ‘normalize electric field’ is usually left checked. If unchecked the peak amplitude of the sinusoidal signals for modulating the two arms has to be set accordingly.
* The modulation voltages (modulation voltage 1 -> Vmod1 and modulation voltage 2 -> Vmod2) are the peak amplitude of the sinusoidal signals and are divided by 2 when the ‘normalize electric field’ is checked.
* The bias voltages are the DC bias voltages, Vbias1 and Vbias2.
* By setting suitable values of Vpi, Vmod1, Vmod2, Vbias1 and Vbias2, the output optical field can be tuned to contain only even components (n = 2, 4, …), odd components (n = 1, 3, …) or both. The primary component can also be suppressed.
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