An optical system, comprising: a polarization scrambler configured to be coupleable to a tunable first optical source configured to generate a coherent optical output including optical energy having a specified tunable wavelength, the polarization scrambler including a polarization rotator and a polarization transformer, the polarization rotator configured to rotate at a first rate, the first rate being a rate of polarization rotation, and the polarization transformer configured to transform the polarization at a second rate, the second rate being a rate of polarization transformation, wherein the first rate is higher than the second rate, the first and second rates are in the range from tens of Hz to kHz; an intravascularly-deliverable optical fiber transducer configured to be coupled to a second optical source and configured to insonify a region of tissue using an ultrasound energy center frequency using energy obtained optically from the second optical source, the transducer further configured to be coupled to the tunable first optical source through the polarization scrambler, the polarization scrambler configured to vary a polarization state of the optical energy provided by the tunable first optical source, the intravascularly-deliverable optical fiber transducer configured to reflect a portion of the optical energy from the first optical source modulated in response to ultrasound, a vibration, pressure, or strain; and a processor circuit configured to: obtain information indicative of the optical energy reflected from the intravascularly-deliverable optical fiber transducer; and process information from the ultrasound, vibration, pressure, or strain modulating the optical energy from the first optical source reflected from the intravascularly-deliverable optical fiber transducer using different polarization states established by the polarization scrambler, wherein the ultrasound energy center frequency has a range of about 5 megahertz to 50 megahertz. a polarization scrambler configured to be coupleable to a tunable first optical source configured to generate a coherent optical output including optical energy having a specified tunable wavelength, the polarization scrambler including a polarization rotator and a polarization transformer, the polarization rotator configured to rotate at a first rate, the first rate being a rate of polarization rotation, and the polarization transformer configured to transform the polarization at a second rate, the second rate being a rate of polarization transformation, wherein the first rate is higher than the second rate, the first and second rates are in the range from tens of Hz to kHz; an intravascularly-deliverable optical fiber transducer configured to be coupled to a second optical source and configured to insonify a region of tissue using an ultrasound energy center frequency using energy obtained optically from the second optical source, the transducer further configured to be coupled to the tunable first optical source through the polarization scrambler, the polarization scrambler configured to vary a polarization state of the optical energy provided by the tunable first optical source, the intravascularly-deliverable optical fiber transducer configured to reflect a portion of the optical energy from the first optical source modulated in response to ultrasound, a vibration, pressure, or strain; and a processor circuit configured to: obtain information indicative of the optical energy reflected from the intravascularly-deliverable optical fiber transducer; and process information from the ultrasound, vibration, pressure, or strain modulating the optical energy from the first optical source reflected from the intravascularly-deliverable optical fiber transducer using different polarization states obtain information indicative of the optical energy reflected from the intravascularly-deliverable optical fiber transducer; and process information from the ultrasound, vibration, pressure, or strain modulating the optical energy from the first optical source reflected from the intravascularly-deliverable optical fiber transducer using different polarization states established by the polarization scrambler, wherein the ultrasound energy center frequency has a range of about 5 megahertz to 50 megahertz.