The Bitwise operators is used to perform bitlevel operations on the operands. The operators are first converted to bitlevel and then calculation is performed on the operands. The mathematical operations such as addition , subtraction , multiplication etc. can be performed at bitlevel for faster processing. In PHP, the operators that works at bit level are:

& (Bitwise AND) : This is a binary operator i.e. it works on two operand. Bitwise AND operator in PHP takes two numbers as operands and does AND on every bit of two numbers. The result of AND is 1 only if both bits are 1.
Syntax:
$First & $Second This will return another number whose bits are set if both the bit of first and second are set.
Example:
Input: $First = 5, $Second = 3 Output: The bitwise & of both these value will be 1. Explanation: Binary representation of 5 is 0101 and 3 is 0011. Therefore their bitwise & will be 0001 (i.e. set if both first and second have their bit set.)

 (Bitwise OR) : This is also binary operator i.e. works on two operand. Bitwise OR operator takes two numbers as operands and does OR on every bit of two numbers. The result of OR is 1 any of the two bits is 1.
Syntax:
$First  $Second This will return another number whose bits are set if either the bit of first or second are set.
Example:
Input: First = 5, Second = 3 Output: The bitwise  of both these value will be 7. Explanation: Binary representation of 5 is 0101 and 3 is 0011. Therefore their bitwise  will be 0111 (i.e. set if either first or second have their bit set.)

^ (Bitwise XOR ) : This is also binary operator i.e. works on two operand. This is also known as Exclusive OR operator. Bitwise XOR takes two numbers as operands and does XOR on every bit of two numbers. The result of XOR is 1 if the two bits are different.
Syntax:
$First ^ $Second This will return another number whose bits are set if one of the bit in first or second is set but not both.
Example:
Input: First = 5, Second = 3 Output: The bitwise ^ of both these value will be 6. Explanation: Binary representation of 5 is 0101 and 3 is 0011. Therefore their bitwise ^ will be 0110 (i.e. set if either first or second have their bit set but not both.)

~ (Bitwise NOT) : This is a unary operator i.e. works on only one operand. Bitwise NOT operator takes one number and inverts all bits of it.
Syntax:
~$number This will invert all the bits of $number.
Example:
Input: number = 5 Output: The bitwise '~' of this number will be 6. Explanation: Binary representation of 5 is 0101. Therefore the bitwise ~ of this will be 1010 (inverts all the bits of the input number)

<< (Bitwise Left Shift) : This is a binary operator i.e. works on two operand. Bitwise Left Shift operator takes two numbers, left shifts the bits of the first operand, the second operand decides the number of places to shift.
Syntax:
$First << $Second This will shift the bits of $First towards the left. $Second decides the number of time the bits will be shifted.
Example:
Input: First = 5, Second = 1 Output: The bitwise << of both these value will be 10. Explanation: Binary representation of 5 is 0101 . Therefore, bitwise << will shift the bits of 5 one times towards the left (i.e. 01010 )
Note: Bitwise left shift with one bit is equivalent to multiplication with 2.

>> (Bitwise Right Shift) : This is also binary operator i.e. works on two operand. Bitwise Right Shift operator takes two numbers, right shifts the bits of the first operand, the second operand decides the number of places to shift.
Syntax:
$First >> $Second This will shift the bits of $First towards the right. $Second decides the number of time the bits will be shifted.
Example:
Input: First = 5, Second = 1 Output: The bitwise >> of both these value will be 2. Explanation: Binary representation of 5 is 0101 . Therefore, bitwise >> will shift the bits of 5 one times towards the right(i.e. 010)
Note: Bitwise right shift with one bit is equivalent to division with 2.
Below is the implementation of Bitwise Operators in PHP:
<?php // PHP code to demonstrate Bitwise Operator. // Bitwise AND $First = 5; $second = 3; $answer = $First & $second ; print_r( "Bitwise & of 5 and 3 is $answer" ); print_r( "\n" ); // Bitwise OR $answer = $First  $second ; print_r( "Bitwise  of 5 and 3 is $answer" ); print_r( "\n" ); // Bitwise XOR $answer = $First ^ $second ; print_r( "Bitwise ^ of 5 and 3 is $answer" ); print_r( "\n" ); // Bitwise NOT $answer = ~ $First ; print_r( "Bitwise ~ of 5 is $answer" ); print_r( "\n" ); // Bitwise Left shift $second = 1; $answer = $First << $second ; print_r( "5 << 1 will be $answer" ); print_r( "\n" ); // Bitwise Right shift $answer = $First >> $second ; print_r( "5 >> 1 will be $answer" ); print_r( "\n" ); ?> 
Output:
Bitwise & of 5 and 3 is 1 Bitwise  of 5 and 3 is 7 Bitwise ^ of 5 and 3 is 6 Bitwise ~ of 5 is 6 5 << 1 will be 10 5 >> 1 will be 2