Optical sensor with multiple detectors or multiple emitters

A noninvasive physiological sensor configured to attach to a finger of a user, the noninvasive physiological sensor comprising:

• a body portion configured to secure to a finger of a user;
• a first emitter configured to emit light at one or more wavelengths into tissue of the finger of the user when the noninvasive physiological sensor is in use, wherein the first emitter is configured to be operably positioned by the body portion at a first side of the finger when the body portion is configured to be secured to the finger;
• a first detector configured to be operably positioned near the first emitter by the body portion at the first side of the finger when the body portion is configured to be secured to the finger such that the first emitter is closer to the first detector than to a second detector, the first detector substantially aligned with the first emitter with respect to a first axis extending through at least a portion of the body portion,
• wherein the first detector is configured to operate in a reflectance mode with respect to the first emitter such that the first detector is configured to detect at least a portion of the light emitted by the first emitter after reflecting from at least a portion of the tissue of the finger of the user, the first detector configured to generate at least one signal responsive to the detected reflected light;
• and
• the second detector configured to be operably positioned far from the first emitter by the body portion at a second side of the finger that is opposite the first side of the finger when the body portion is configured to be secured to the finger such that the first emitter is farther from the second detector than from the first detector, the second detector substantially aligned with the first emitter with respect to a second axis extending through at least portion of the body portion,
• wherein the second detector is configured to operate in a transmittance mode with respect to the first emitter such that the second detector is configured to detect at least a portion of the light emitted by the first emitter after transmitting through at least a portion of the tissue of the finger of the user, the second detector configured to generate at least one signal responsive to the detected transmitted light.