Claims
- 1. A control circuit for generating a modulating output signal for driving an optical path length modulator in a tunable laser comprising:waveform generation circuitry for generating an analog signal; an amplifier circuit to receive the analog signal and configured to produce an amplified analog signal; and a transformer including a primary coil coupled to the amplifier circuit in a push-pull configuration and a secondary coil for providing the modulating output signal.
- 2. The control circuit as recited in claim 1 wherein the waveform generation circuitry includes a programmable logic device for generating a digital output signal.
- 3. The control circuit as recited in claim 2 wherein a signal conversion circuit converts said digital signal to said analog signal.
- 4. The control circuit as recited in claim 3 wherein the signal conversion circuit comprises a low-pass filter.
- 5. The control circuit as recited in claim 4 wherein said digital signal is a pulse width modulated signal.
- 6. The control circuit as recited in claim 1 wherein said amplifier circuit includes a pair of operational amplifiers having outputs coupled to source and sink current flowing through said primary coil of said transformer.
- 7. A laser system comprising:a tunable laser including an optical path length modulator; and a control circuit for generating a modulating output signal for driving the optical path length modulator, the control circuit including: waveform generation circuitry for generating an analog signal; an amplifier circuit to receive the analog signal and configured to produce an amplified analog signal; and a transformer including a primary coil coupled to the amplifier circuit in a push-pull configuration and a secondary coil for providing the modulating output signal.
- 8. The laser system as recited in claim 7 wherein the waveform generation circuitry includes a programmable logic device for generating a digital output signal.
- 9. The laser system as recited in claim 8 wherein a signal conversion circuit converts said digital signal to said analog signal.
- 10. The laser system as recited in claim 9 wherein the signal conversion circuit comprises a low-pass filter.
- 11. The laser system as recited in claim 10 wherein said digital signal is a pulse width modulated signal.
- 12. The laser system as recited in claim 6 wherein said amplifier circuit includes a pair of operational amplifiers having outputs coupled to source and sink current flowing through said primary coil of said transformer.
- 13. The control circuit as recited in claim 1 wherein the path length modulator comprises an electro-optic material.
- 14. The control circuit as recited in claim 13 wherein the electro-optic material is lithium niobate.
- 15. The control circuit as recited in claim 1 wherein a frequency of said analog signal is high enough to provide coherence control of said tunable laser but also low enough to prevent interference with information modulated on a carrier signal generated by said tunable laser.
- 16. The control circuit as recited in claim 4 wherein said low-pass filter and said amplifier circuit comprise a class D amplifier coupled to drive said primary coil.
- 17. The laser system of claim 7, further comprising a network interface coupled to said laser system and to provide remote operation of said laser system through said network interface.
Parent Case Info
This is a Divisional of U.S. application Ser. No. 09/900,108, filed Jul. 6, 2001, now U.S. Pat. No. 6,631,146.
US Referenced Citations (12)
Foreign Referenced Citations (2)
Number |
Date |
Country |
WO 9805105 |
Feb 1998 |
WO |
WO 0104999 |
Jan 2001 |
WO |
Non-Patent Literature Citations (1)
Entry |
PCT Search Report, Oct. 16, 2002. |