Reconfigurable spectroscopy system

• US 10,677,989 B2
• Filed: 07/03/2018
• Issued: 06/09/2020
• Est. Priority Date: 07/05/2017
• Status: Active Grant

• Current Assignee: Rockley Photonics Limited
• Original Assignee: Rockley Photonics Limited
• Inventors: Abediasl, Hooman, Rickman, Andrew George, Nagra, Amit Singh, Trita, Andrea, Schrans, Thomas Pierre, Zilkie, Aaron John, Srinivasan, Pradeep
• Primary Examiner(s): Rahll, Jerry
• Application Number:
  US16/026,953
• Publication Number:
  US 20190011639A1
• Time in Patent Office: 707 Days
• Field of Search: None
• CPC Class Codes: G01J 1/4257 applied to monitoring the characteristics of a beam, e.g. laser beam, headlamp beam monitoring arrangements for lasers in general H01S3/0014
• CPC Class Codes: G01J 2003/106 the two sources being alternating or selectable, e.g. in two ranges or line:continuum
• CPC Class Codes: G01J 3/08 Beam switching arrangements
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G02B 6/29301 based on a phased array of light guides integrated arrayed waveguide gratings G02B6/12009
• CPC Class Codes: G02B 6/29386 Interleaving or deinterleaving, i.e. separating or mixing subsets of optical signals, e.g. combining even and odd channels into a single optical signal
• CPC Class Codes: G02B 6/3548 1xN switch, i.e. one input and a selectable single output of N possible outputs
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/1305 Feedback control systems
• CPC Class Codes: H01S 3/1307 Stabilisation of the phase
• CPC Class Codes: H01S 3/2391 emitting at different wavelengths

Abstract

A reconfigurable spectroscopy system comprises tunable lasers and wavelength lockers to lock to accurate reference wavelengths. Band combiners with differently optimized wavelength ranges multiplex the optical signal over the time domain, to emit a plurality of reference wavelengths for spectroscopy applications. The power requirements are greatly reduced by multiplexing over the time domain in time slots which do not affect sampling and receiving of the spectroscopy data.

Claims

1. A device comprising:

a plurality of tunable lasers generating a plurality of wavelengths;

a plurality of wavelength lockers to reduce wavelength noise from the plurality of wavelengths;

a plurality of band combiners each configured to combine a different wavelength range than other band combiners of the plurality of band combiners;

a plurality of switches, each switch receiving an output of a corresponding band combiner of the plurality of band combiners, each switch outputting a plurality of switched wavelengths;

a plurality of broadband combiners receiving outputs of the plurality of switches; and

a plurality of emitters to emit a plurality of reference wavelengths, each emitter receiving an output of a corresponding broadband combiner of the plurality of broadband combiners.

2. The device of claim 1, wherein each wavelength locker of the plurality of wavelength lockers is between a tunable laser of the plurality of tunable lasers and a band combiner of the plurality of band combiners.

3. The device of claim 1, wherein the plurality of wavelength lockers comprises a plurality of optical channel monitors located after the plurality of band combiners, and feeding back to the plurality of tunable lasers.

4. The device of claim 1, wherein each band combiner of the plurality of band combiners is configured to operate within a wavelength range of 100 nm.

5. The device of claim 1, wherein each wavelength locker of the plurality of wavelength lockers comprises feed-forward or feedback noise cancellation, and wavelength locking circuits.

6. The device of claim 3, wherein each optical channel monitor of the plurality of optical channel monitor:

comprises;

one input configured to receive a portion of light from a tunable laser;

an arrayed waveguide grating;

a first photodiode outputting a first current; and

a second photodiode outputting a second current; and

is configured to monitor a ratio of the first current to the second current, to stabilize a target wavelength.

7. A device comprising:

a plurality of tunable lasers generating a plurality of wavelengths;

a plurality of wavelength lockers to reduce wavelength noise from the plurality of wavelengths;

a plurality of band combiners each configured to combine a different wavelength range than other band combiners of the plurality of band combiners;

a broadband combiner receiving outputs of the plurality of band combiners;

an optical phased array switch comprising at least one arrayed waveguide grating; and

a plurality of emitters to emit a plurality of reference wavelengths, each emitter receiving an output of the optical phased array switch.

8. The device of claim 7, wherein the plurality of wavelength lockers comprises a plurality of optical channel monitors located after the plurality of band combiners, and feeding back to the plurality of tunable lasers.

9. The device of claim 8, wherein each optical channel monitor of the plurality of optical channel monitor:

comprises;

one input configured to receive a portion of light from a tunable laser;

an arrayed waveguide grating;

a first photodiode outputting a first current; and

a second photodiode outputting a second current; and

is configured to monitor a ratio of the first current to the second current, to stabilize a target wavelength.

10. The device of claim 7, wherein each band combiner of the plurality of band combiners is configured to operate within a wavelength range of 100 nm.

11. A method comprising:

generating a plurality of wavelengths by a plurality of tunable lasers;

reducing wavelength noise from the plurality of wavelengths by a plurality of wavelength lockers;

combining the plurality of wavelengths into wavelength ranges by a plurality of band combiners;

switching the wavelength ranges by a plurality of switches;

multiplexing over a time domain the plurality of wavelength ranges into a plurality of broadband combiners, each broadband combiner of the plurality of broadband combiners outputting to a corresponding emitter of a plurality of emitters; and

emitting the multiplexed wavelengths by the plurality of emitters.