Optical sensing module
An optical sensing module suitable for wearable devices, the optical sensing module comprising: a silicon or silicon nitride transmitter photonic integrated circuit (PIC), the transmitter PIC comprising: a plurality of lasers, each laser of the plurality of lasers operating at a wavelength that is different from the wavelength of the others; an optical manipulation region, the optical manipulation region comprising one or more of: an optical modulator, optical multiplexer (MUX); and additional optical manipulation elements; and one or more optical outputs for light originating from the plurality of lasers.
1. An optical sensing module suitable for wearable devices, the optical sensing module comprising:
a silicon or silicon nitride transmitter photonic integrated circuit (PIC), the transmitter PIC comprising:
a plurality of lasers, each laser of the plurality of lasers providing a laser output at a wavelength that is different from the wavelength of the laser outputs of the other lasers within the plurality of lasers;
an optical manipulation region, the optical manipulation region comprising one or more of: an optical modulator, optical multiplexer (MUX); and additional optical manipulation elements; and
one or more optical sensor module outputs for light originating from the plurality of lasers to exit the optical sensing module;
wherein:
the plurality of lasers comprises one or more hybrid DBR lasers, each hybrid DBR laser having a III-V RSOA gain chip or coupon that is hybrid integrated to the PIC such that an optical mode in the III-V RSOA gain chip or coupon is edge-coupled to one or more waveguides of the PIC; and
wherein each of the lasers of the plurality of lasers is switchable, to switch between an on configuration and an off configuration.
2. The optical sensing module of claim 1 , wherein the additional optical manipulation elements comprise one or more of: power taps, power splitter(s), filter(s), mirror(s) and polarization rotator(s).
3. The optical sensing module of claim 1 , wherein, in any given time window, no more than one laser of the plurality of lasers is turned on.
4. The optical sensing module of claim 1 , wherein the switching between an on and an off configuration for each laser within the plurality of lasers is carried out in a predetermined sequence.
5. The optical sensing module of claim 1 , further comprising a plurality of LEDs, the LEDs operating at wavelengths within the range of 400 nm to 950 nm, and the plurality of lasers operating at wavelengths within the range of 1150 nm to 2500 nm, each LED operating at a wavelength which is different from the wavelengths of the other LEDs making up the plurality of LEDs.
6. The optical sensing module of claim 1 , further comprising one or more photodetectors.
7. The optical sensing module of claim 6 , wherein the one or more photodetectors are located on the transmitter PIC such that the PIC is a transmitter/receiver PIC.
8. The optical sensing module of claim 6 , wherein the one or more photodetectors are located separately from the transmitter PIC.
9. The optical sensing module of claim 6 , further comprising a 2D array of photodetectors, the 2D array of photodetectors arranged such that different photodetectors have different lateral separation distances from the one or more optical outputs.
10. The optical sensing module of claim 6 , wherein the one or more photodetectors are located on a separate chip that is vertically integrated and mounted on the same substrate shared with the transmitter PIC.
11. The optical sensing module of claim 10 , wherein the one or more photodetectors are located on a carrier beside the transmitter PIC.
12. The optical sensing module of claim 6 , wherein the one or more photodetectors comprises a plurality of photodetectors, each of the plurality of photodetectors operating over a different range of wavelengths.
13. The optical sensing module of claim 6 wherein the one or more photodetectors are arranged to function as a spectrophotometer for diffuse reflectance generated at a sample when light from one or more of the plurality of lasers is used to illuminate a sample.
14. The optical sensing module of claim 6 , wherein the one or more photodetectors are arranged to receive light originating from one or more of the plurality of lasers, the light having been transmitted through a sample.
15. The optical sensing module of claim 1 , further comprising one or more of: laser driver(s), modulator driver(s), phase controller(s), TIA(s), power management IC(s), multiplexer circuit, micro-controller unit(s) (MCU), FPGA(s).
16. The optical sensing module of claim 1 , comprising both silicon waveguides and SiN waveguides.
17. The optical sensing module of claim 1 , wherein one or more photodetectors or LEDs are located under one or more respective microlenses wherein one or more of the one or more microlenses comprises a thin film stack of DBR filters.
18. The optical sensing module of claim 1 , comprising a processor configured to:
apply a pre-trained algorithm to reflectance data taken at a wavelength corresponding to a water absorption peak, to convert reflectance measurements into a predicted temperature.
19. The optical sensing module of claim 1 , further comprising an optical multiplexer (MUX) which directly couples the laser output from each of the plurality of lasers directly to a single waveguide of the PIC, the single waveguide of the PIC coupling light to the one or more optical sensor module outputs.