Polarization Extinction Ratio Calculator with Steps

Polarization Extinction Ratio Formula:

\[ PER = 10 \times \log_{10}\left(\frac{P_{max}}{P_{min}}\right) \]

Polarization Extinction Ratio (PER):

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1. What is Polarization Extinction Ratio (PER)?

Definition: PER measures the quality of polarization in optical systems by comparing maximum and minimum power states.

Purpose: It quantifies how well a polarized light source maintains its polarization state or how effectively a polarizer works.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ PER = 10 \times \log_{10}\left(\frac{P_{max}}{P_{min}}\right) \]

Where:

\( PER \) — Polarization Extinction Ratio (dB)
\( P_{max} \) — Maximum power in the desired polarization (W)
\( P_{min} \) — Minimum power in the orthogonal polarization (W)

Explanation: The ratio of maximum to minimum power is converted to decibels (dB) using a logarithmic scale.

3. Importance of PER Measurement

Details: Higher PER values indicate better polarization purity, which is crucial in fiber optics, laser systems, and optical communications.

4. Using the Calculator

Tips: Enter both power values in watts. P_max must be greater than P_min. Results are given in decibels (dB).

5. Frequently Asked Questions (FAQ)

Q1: What is a good PER value?
A: Values above 20 dB are generally good, with high-quality systems achieving 30 dB or more.

Q2: Can PER be negative?
A: No, since P_max should always be greater than P_min, PER is always positive.

Q3: How do I measure P_max and P_min?
A: Use a power meter while rotating a polarizer to find maximum and minimum transmission states.

Q4: What affects PER in optical systems?
A: Factors include polarizer quality, fiber bending, connectors, and environmental stress on components.

Q5: What's the difference between PER and polarization-dependent loss (PDL)?
A: PER measures polarization purity, while PDL measures how much loss varies with polarization state.