System, apparatus and method for utilizing optical dispersion for fourier-domain optical coherence tomography
An apparatus can be provided which can include a laser arrangement which can be configured to provide a laser radiation, and can include an optical cavity. The optical cavity can include a dispersive optical first arrangement which can be configured to receive and disperse at least one first electro-magnetic radiation so as to provide at least one second electro-magnetic radiation. Such cavity can also include an active optical modulator second arrangement which can be configured to receive and modulate the at least one second radiation so as to provide at least one third electro-magnetic radiation. The optical cavity can further include a dispersive optical third arrangement which can be configured to receive and disperse at least one third electro-magnetic radiation so as to provide at least one fourth electro-magnetic radiation. For example, actions by the first, second and third arrangements can cause a spectral filtering of the fourth electro-magnetic radiation(s) relative to the first electro-magnetic radiation(s). The laser radiation can be associated with the fourth radiation(s), and a wavelength of the laser radiation can be controlled by the spectral filtering caused by the actions by the first, second and third arrangements.
1. A source for providing electromagnetic radiation within a particular spectral range, comprising:
a ring-shaped optical resonator for circulating a plurality of wavelength bands including:
a first optical phase modulator,
a chromatic dispersion device,
a second optical phase modulator, and
a multi-line spectral domain filter; and
a controller coupled to the first optical phase modulator and the second optical phase modulator which is configured to drive the first optical phase modulator and the second optical phase modulator with particular time-varying waveforms,
the chromatic dispersion device being configured between the first optical phase modulator and the second optical phase modulator to provide chromatic dispersion so as to subject each of the plurality of wavelength bands to a respective plurality of different time delays,
the first optical phase modulator and the second optical phase modulator being configured to create spectral broadening by the first optical phase modulator and spectral recovery by the second optical phase modulator of a particular wavelength band of the plurality of wavelength bands by modulating a first phase using the first optical phase modulator with a particular set of frequencies and a particular set of amplitudes and, after a particular time delay, modulating a second phase opposite the first phase using the second optical phase modulator,
the particular time delay being determined so as to create the spectral recovery for the particular wavelength band of the plurality of wavelength bands, and
the multi-line spectral domain filter being configured to provide multi-line spectral filtering with narrow bandwidths in order to induce power loss for each of the plurality of wavelength bands except for the particular wavelength band.
2. The apparatus of claim 1 , wherein the chromatic dispersion device is a first chromatic dispersion device, and
wherein the ring-shaped optical resonator further comprises a second chromatic dispersion device,
wherein the second chromatic dispersion device is configured to provide chromatic dispersion compensation to an output of the multi-line spectral domain filter in order to compensate a group delay dispersion within the ring-shaped optical resonator and match a roundtrip frequency for each of the plurality of wavelength bands.
3. The apparatus of claim 2 , wherein the first chromatic dispersion device comprises at least one of an optical fiber, a dispersion-compensating optical fiber, a photonic crystal fiber, a chirped fiber Bragg grating (FBG), or a grating-based dispersive path.
4. The apparatus of claim 3 , wherein the second chromatic dispersion device comprises at least one of an optical fiber, a dispersion-compensating optical fiber, a photonic crystal fiber, a chirped fiber Bragg grating (FBG), or a grating-based dispersive path.
5. The apparatus of claim 4 , wherein the first chromatic dispersion device is a different type of device from the second chromatic dispersion device.
6. The apparatus of claim 1 , wherein at least one of the first optical phase modulator or the second optical phase modulator comprises an electro-optic phase modulator.
7. The apparatus of claim 6 , wherein at least one of the first optical phase modulator or the second optical phase modulator comprises a Lithium-Niobate phase modulator.
8. The apparatus of claim 1 , wherein the multi-line spectral domain filter comprises a Fabry-Perot etalon.
9. The apparatus of claim 1 , wherein the ring-shaped optical resonator further comprises an optical amplifier.
10. The apparatus of claim 9 , wherein the optical amplifier comprises at least one of a semiconductor optical amplifier, a doped-fiber amplifier, or a Raman amplifier.
11. The apparatus of claim 1 , wherein the ring-shaped optical resonator further comprises an output coupler which is configured to emit a first output electromagnetic radiation based on the plurality of wavelength bands.
12. The apparatus of claim 1 , wherein the particular time delay is adjusted so that each of the plurality of wavelength bands is spectrally recovered by the second optical phase modulator in order of wavelength to produce a wavelength-stepped laser.
13. A method for providing electromagnetic radiation within a particular spectral range, comprising:
providing a ring-shaped optical resonator for circulating a plurality of wavelength bands, the ring-shaped optical resonator including:
a first optical phase modulator,
a chromatic dispersion device,
a second optical phase modulator, and
a multi-line spectral domain filter,
the chromatic dispersion device being configured between the first optical phase modulator and the second optical phase modulator;
driving, using a controller, the first optical phase modulator and the second optical phase modulator with particular time-varying waveforms;
generating, using the chromatic dispersion device, chromatic dispersion so as to subject each of the plurality of wavelength bands to a respective plurality of different time delays;
modulating a first phase using the first optical phase modulator with a particular set of frequencies and a particular set of amplitudes and, after a particular time delay, modulating a second phase opposite the first phase using the second optical phase modulator,
the particular time delay being determined so as to create spectral recovery for a particular wavelength band of the plurality of wavelength bands; and
creating, based on modulating the first phase and the second phase, spectral broadening by the first optical phase modulator and the spectral recovery by the second optical phase modulator of the particular wavelength band of the plurality of wavelength bands,
the multi-line spectral domain filter being configured to provide multi-line spectral filtering with narrow bandwidths in order to induce power loss for each of the plurality of wavelength bands except for the particular wavelength band.
14. The method of claim 13 , wherein the chromatic dispersion device is a first chromatic dispersion device,
wherein the ring-shaped optical resonator further comprises a second chromatic dispersion device, and
wherein the method further comprises:
providing, by the second chromatic dispersion device, chromatic dispersion compensation to an output of the multi-line spectral domain filter in order to compensate a group delay dispersion within the ring-shaped optical resonator and match a roundtrip frequency for each of the plurality of wavelength bands.
15. The method of claim 14 , wherein the first chromatic dispersion device comprises at least one of an optical fiber, a dispersion-compensating optical fiber, a photonic crystal fiber, a chirped fiber Bragg grating (FBG), or a grating-based dispersive path.
16. The method of claim 15 , wherein the second chromatic dispersion device comprises at least one of an optical fiber, a dispersion-compensating optical fiber, a photonic crystal fiber, a chirped fiber Bragg grating (FBG), or a grating-based dispersive path.
17. The method of claim 16 , wherein the first chromatic dispersion device is a different type of device from the second chromatic dispersion device.
18. The method of claim 13 , wherein at least one of the first optical phase modulator or the second optical phase modulator comprises an electro-optic phase modulator.
19. The method of claim 18 , wherein at least one of the first optical phase modulator or the second optical phase modulator comprises a Lithium-Niobate phase modulator.
20. The method of claim 13 , wherein the multi-line spectral domain filter comprises a Fabry-Perot etalon.
21. The method of claim 13 , wherein the ring-shaped optical resonator further comprises an optical amplifier.
22. The method of claim 21 , wherein the optical amplifier comprises at least one of a semiconductor optical amplifier, a doped-fiber amplifier, or a Raman amplifier.
23. The method of claim 13 , wherein the ring-shaped optical resonator further comprises an output coupler, and
wherein the method further comprises:
emitting, by the output coupler, a first output electromagnetic radiation based on the plurality of wavelength bands.
24. The method of claim 13 , further comprising:
adjusting the particular time delay so that each of the plurality of wavelength bands is spectrally recovered by the second optical phase modulator in order of wavelength to produce a wavelength-stepped laser.