Patent ID: 11885684
Assignee: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 16:
17. A method of Raman spectroscopy, comprising:
receiving, via an optical fiber, at a first port of a multi-port optical coupler integrated with a semiconductor substrate of a photonic integrated chip (PIC), a Raman pump beam and fluorescence induced by the Raman pump beam in the optical fiber;
coupling, by the multi-port optical coupler, the Raman pump beam from the first port to a second port of the multi-port optical coupler at a first coupling ratio;
guiding, via a sample waveguide coupled to the second port, the Raman pump beam and the fluorescence away from the second port;
exciting a sample in optical communication with the sample waveguide with the Raman pump beam via evanescent coupling;
receiving, via the sample waveguide, a scattering signal from the sample in response to the excitation;
guiding, via the sample waveguide, the scattering signal towards the second port;
coupling, by the multi-port optical coupler, the scattering signal from the second port to a third port of the multi-port optical coupler at a second coupling ratio different than the first coupling ratio; and
guiding, via an output waveguide coupled to the third port, the scattering signal to a detector.