The main obstacle in realization of a totally implantable hearing aid is a lack of reliable implantable microphone. In this paper we have described a potentially miniature fiber-optic vibrometer based on a modified Michelson interferometer, designed to serve as a middle-ear microphone for totally implantable cochlear- or middle-ear hearing aids. A model of the sensing system was used for in-vitro and in-vivo investigation of acoustical response of sheep's middle-ear ossicles. Surgical and implantation procedure of introducing the sensing optical fiber into the middle-ear and its aiming at the incus was investigated and described here in detail. The frequency responses of the incus was measured while a cadaver and living sheep was exposed to the sinusoidal acoustical excitation of 40–90 dB SPL, in the frequency range from 100 Hz to 10 kHz. The amplitude of the incus vibration was found to be in the range between 10 pm to 100 nm, strongly depending on the frequency, with a lot of resonant peaks, corresponding mainly to the natural outer ear canal gain. The noise floor in the experiments was about 2 pm/Hz^1/2, but recently we have decreased it to < 0.5 pm/Hz^1/2, which corresponds to a minimal detectable sound level of 31–35 dB(A) SPL for humans. The histological examination of temporal bones of cadaver animals and the intensity of in-vivo optical signal demonstrated that the aiming of the sensing fiber to the target has been preserved for five months after the implantation.

实现完全可植入助听器的主要障碍是缺乏可靠的可植入麦克风。在本文中，我们描述了一种基于改良的迈克尔逊干涉仪的潜在微型光纤振动计，旨在用作完全植入式人工耳蜗或中耳助听器的中耳麦克风。传感系统的模型用于体外和体内羊中耳小骨的声学反应研究 将传感光纤引入中耳并瞄准中耳的手术和植入程序已在此处进行了详细研究和描述。在尸体和活羊暴露在100 Hz至10 kHz频率范围内的40–90 dB SPL的正弦声激励下时，测量了砧骨的频率响应。已发现，砧骨振动的幅度在10 pm至100 nm之间的范围内，强烈取决于频率，并具有许多共振峰，主要对应于自然外耳道增益。实验中的本底噪声约为2 pm / Hz ^1/2，但最近我们将其降低至<0.5 pm / Hz ^1/2，对应于人类的最低可检测声级31–35 dB（A）SPL。对尸体颞骨的组织学检查和体内光信号的强度表明，植入后，感测纤维对目标的瞄准已保留了五个月。