Optical fibre communication uses the frequency range of

Options

A. `10^(9)-10^(10)` Hz
B. `10^(5)` to `10^(6)` Hz
C. `10^(14)` to `10^(15)` Hz
D. `10^(16)` to `10^(17)` Hz

Answer

To solve the question about the frequency range used in optical fiber communication, we can follow these steps:

### Step 1: Understand Optical Fiber Communication
Optical fiber communication utilizes light signals to transmit data. This means that the communication relies on electromagnetic waves in the optical range.

### Step 2: Identify the Frequency Range of Light
The frequency of electromagnetic waves can be calculated using the formula:
\[ f = \frac{c}{\lambda} \]
where \( f \) is the frequency, \( c \) is the speed of light (approximately \( 3 \times 10^8 \) m/s), and \( \lambda \) is the wavelength.

### Step 3: Determine the Wavelength Range for Optical Fiber
Optical fibers typically operate in the wavelength range of approximately 400 nm to 700 nm (visible light spectrum). However, for communication purposes, they often use wavelengths around 1550 nm and 1310 nm, which are in the infrared range.

### Step 4: Convert Wavelength to Frequency
Using the wavelength of 1550 nm (which is \( 1550 \times 10^{-9} \) m):
\[ f = \frac{3 \times 10^8 \text{ m/s}}{1550 \times 10^{-9} \text{ m}} \approx 1.93 \times 10^{14} \text{ Hz} \]
And for 1310 nm (which is \( 1310 \times 10^{-9} \) m):
\[ f = \frac{3 \times 10^8 \text{ m/s}}{1310 \times 10^{-9} \text{ m}} \approx 2.29 \times 10^{14} \text{ Hz} \]

### Step 5: Identify the Correct Frequency Range
From the calculations, we see that the frequency range for optical fiber communication is approximately \( 10^{14} \) Hz to \( 10^{15} \) Hz.

### Step 6: Choose the Correct Option
Given the options:
1. \( 10^9 \) to \( 10^{10} \) Hz
2. \( 10^5 \) to \( 10^6 \) Hz
3. \( 10^{14} \) to \( 10^{15} \) Hz
4. \( 10^{16} \) to \( 10^{17} \) Hz

The correct answer is option 3: \( 10^{14} \) to \( 10^{15} \) Hz.

### Final Answer
Optical fiber communication uses the frequency range of \( 10^{14} \) to \( 10^{15} \) Hz.

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