Re-circulating optical pulse generator
AssigneeBookham Technology PLC
InventorKelvin Prosyk
Life of this patent
Estimating the term…
Abstract
A Mach-Zehnder Modulator (MZM) pulse generator is provided having an increased power output. Power carved from the output signal in creating the pulses is recycled back to the input of the pulse generator via a feedback arm. Careful design of the length of the feedback arm such that a feedback signal has a propagation time of (2n+1)T/2 to complete one loop (n being a non-negative integer and T being the pulse period) allows a 50% duty cycle to be obtained using a driving frequency of only one half of the pulse frequency.
Claims20
An optical pulse generator for receiving a continuous wave optical signal and producing a series of pulses, the optical pulse generator comprising:
- a Mach-Zehnder Modulator (MZM) having a first input arm for receiving the continuous wave optical signal, a second input arm, a first output arm for producing the series of pulses, and a second output arm, and configured to operate such that substantially none of a continuous wave optical signal enters the second output arm when the MZM is not being driven by a variable voltage;
- a feedback arm coupling the second output arm to the second input arm, and having a length such that a signal travelling in a loop around the MZM and the feedback arm has a propagation time given by
- 4 τ = ( 2 n + 1 ) T 2 .
- where n is a non-negative integer and T is a pulse period of the pulses;
- and
- a Direct Current phase adjuster in the feedback arm.
An optical pulse generator for receiving a continuous wave optical signal and producing a series of pulses, the optical pulse generator comprising:
- a Mach-Zehnder Modulator (MZM) having a first input arm for receiving the continuous wave optical signal, a second input arm, a first output arm for producing the series of pulses, and a second output arm, and configured to operate such that substantially none of a continuous wave optical signal enters the second output arm when the MZM is not being driven by a variable voltage;
- and
- a feedback arm coupling the second output arm to the second input arm, and having a length such that a signal travelling in a loop around the MZM and the feedback arm has a propagation time given by
- 5 τ = ( 2 n + 1 ) T 2
- where n is a non-negative integer and T is a pulse period of the pulses, and such that there is substantially no phase difference between a feedback signal propagating along the feedback arm and the continuous wave optical signal upon entering the MZM.
Dependencies are inferred from the claim text.