Time measuring device

Abstract

The invention relates to a timepiece (100), in particular a wristwatch, comprising an electro-optical converter device (1) with at least one electro-optical converter (10; 11, 12), an opto-electrical converter device (2), a first signal path (3) leading into the opto-electrical converter device (2) via a first waveguide (61), a second signal path (4) leading into the opto-electrical converter device (2) either directly or via a second waveguide (62), a control device (5) and a useful signal generating device (103). The first signal path (3) and the second signal path (4) are designed such that the propagation time of the first optical clock signal in the first signal path (3) and the propagation time of the second optical clock signal in the second signal path (4) are different from each other.

Description

[Technical Field]

[0001] The present invention relates to a time measurement device. [Background technology]

[0002] From the prior art, quartz watches and automatic or hand-wound mechanical watches are known. Quartz watches keep time by the frequency of a crystal oscillator. On the other hand, automatic mechanical watches (also called self-winding watches) and hand-wound mechanical watches are generally controlled by the oscillations of a balance wheel, which controls what is known as the escapement. Other time measurement devices, such as navigational instruments, usually have their time measurement clocked by the frequency of a crystal oscillator, just like quartz watches. Summary of the Invention [Problem to be solved by the invention]

[0003] SUMMARY OF THE INVENTION An object of the present invention is to provide a time measurement device that is as precise as possible. [Means for solving the problem]

[0004] The following describes a time measuring device comprising an electro-optical converter device with at least one or two parallel electro-optical converters, in particular an opto-electrical converter device with one or two parallel opto-electrical converters, a first signal path, a second signal path, a control device and a useful signal generating device.

[0005] The first signal path comprises a waveguide (referred to as the first waveguide) and leads from the electro-optical converter device through the waveguide into the opto-electrical converter device / photoelectric converter device, so that the first signal path may also comprise, at least in part, the opto-electrical converter device in addition to the waveguide.

[0006] The second signal path leads from the electro-optical converter device directly or via a second waveguide into the opto-electrical converter device / optical-to-electrical converter device, and thus the second signal path comprises, at least in part, the opto-electrical converter device and optionally the second waveguide.

[0007] The electro-optical converter device is configured to generate and provide a first clock optical signal into the waveguide and a second clock optical signal into the second signal path. The electro-optical converter device is configured to generate a first electrical signal based on the first clock optical signal and generate a second electrical signal based on the second clock optical signal. Furthermore, the first signal path and the second signal path are configured so that the transit time of the first clock optical signal in the first signal path and the transit time of the second clock optical signal in the second signal path are different from each other. In particular, based on the control signal, it is specified that two optical signals (first and second optical signals) with the same frequency and no phase shift are generated within the electro-optical converter device for the two signal paths. The two optical signals differ in phase shift only due to the difference in transit time within the two signal paths.

[0008] The control device is configured to generate a control signal based on a phase difference between the first electrical signal and the second electrical signal, and to drive the electro-optical converter device with the control signal to generate two optical signals. The control signal for controlling the electro-optical converter device corresponds to an output signal of the control device. In the context of the present invention, the control device may also be specifically referred to as a control unit.

[0009] The useful signal generator is configured to generate a useful signal that clocks time based on the frequency of the control signal.

[0010] According to an advantageous embodiment of the invention, the time measurement device can be a clock, in particular a wristwatch, with a clock display. In this case, the clock display is configured to display the time based on a useful signal. According to a further advantageous embodiment of the invention, the time measurement device can be a navigation device time measurement device. The operating mode of the navigation device is based on time measurement, in particular on measuring the time it takes for a radio signal to travel from at least three satellites to the navigation device. The more accurate the time measurement, the more accurate the position determination of the navigation device. If the time measurement device is not a clock, it can preferably comprise an application-oriented unit. The application-oriented unit can be implemented as software and / or hardware. If the time measurement device is a navigation device time measurement device, the application-oriented unit can be a position determination unit configured to determine the position of the navigation device using a useful signal as a comparison signal.

[0011] The time measurement device according to the present invention has the advantage that the waveguide of the first signal path is a frequency-determining element, in particular an exclusive frequency-determining element. In other words, the frequency used as the frequency of the clock of the time measurement device (the clock frequency) is based, in particular, exclusively on the transit time of light through the waveguide of the first signal path. This is achieved, in particular, by the provision of the second signal path and the control device described above. As a result, the less stable and less calculable signal delays caused by the electronic components of the time measurement device, in particular the electro-optical and opto-electrical converter devices, have little or no effect on the clock frequency due to the light transit time in the waveguide. In particular, the response times of the electro-optical and opto-electrical converter devices can be excluded from the determination of the clock frequency. In other words, the duration of the process of converting an electrical signal to an optical signal by the electro-optical converter device and the process of converting an optical signal to an electrical signal by the opto-electrical converter device are not taken into account when determining the frequency associated with the clock of the time measurement device.

[0012] The advantage of an optically controlled time measurement device configured as a watch is that the generation of clock pulses is independent of the influence of the movement and position (horizontal or vertical) of the watch. Therefore, in particular, an optically controlled watch according to the invention is significantly more accurate than a watch with a mechanical oscillator, in which the movement of the wearer's wrist suppresses or accelerates the oscillations of the balance, the tension of the clockwork spring influences the escapement and thus the frequency of the balance / escapement tandem, and the position of the spring influences the oscillation characteristics of the balance. If the time measurement device is a navigation time measurement device, the invention allows for increased navigation accuracy compared to navigation devices with time measurement based on a quartz oscillator.

[0013] Furthermore, problems that arise in time measurement devices with frequency-determining oscillating crystals, such as deviations in the oscillation frequency caused by the incorporation of impurities into the oscillating crystal over time or other time-dependent factors, the so-called "aging" of the oscillating crystal, do not occur in the proposed optically controlled time measurement device. Furthermore, the generation of clock pulses by a piezoelectric oscillating crystal, like the generation of clock pulses by a balance, is based on mechanical vibrations, specifically piezoelectrically excited mechanical vibrations of the oscillating crystal. Mechanical vibrations of this type are more susceptible to attenuation than the optical clock signal in the proposed time measurement device. Therefore, the optically controlled time measurement device according to the invention is more accurate than time measurement devices in which clock pulses are generated by the vibrations of a piezoelectric oscillating crystal.

[0014] Furthermore, the optically controlled time measurement device according to the present invention offers great flexibility in selecting the clock frequency of the time measurement device based on the light transit time in the waveguide of the first signal path, as already explained. The clock frequency can be easily selected according to the respective requirements of the time measurement device and / or the design requirements of the owner / wearer of the time measurement device configured as a clock / watch. Thus, for example, it is possible to simply design the waveguide of the first signal path so that the clock frequency has a specific value.

[0015] The electro-optical converter device, the first signal path, the second signal path and the control device advantageously form a loop, in particular a control loop.

[0016] Advantageously, the time measuring device, in particular the useful signal generating device, can be provided with an interface for reading out the frequency of the useful signal.

[0017] It will be appreciated that the first electrical signal and the second electrical signal are also advantageously clock signals, since the first optical signal and the second optical signal are clock signals.

[0018] The first optical clock signal and / or the second optical clock signal may each in particular be an analog optical clock signal, in particular an optical sinusoidal signal. Correspondingly, the first electrical signal and / or the second electrical signal may each in particular be an analog electrical signal, in particular an electrical sinusoidal signal. However, shapes other than sinusoidal, for example rectangular waveforms, are also possible for the optical or electrical signals. Instead of an analog form, the first optical clock signal and / or the second optical clock signal may each in particular be digital (pulsed). Correspondingly, the first electrical signal and / or the second electrical signal may each in particular be a digital (pulsed) electrical signal.

[0019] The control device preferably comprises a phase comparator, a loop filter (LF) for integrating an output signal of the phase comparator, and an oscillator drivable by the output signal of the loop filter, wherein the control signal for controlling the electro-optical converter device corresponds to or at least is based on the output signal of the drivable oscillator.

[0020] In the context of the present invention, a phase comparator may also be referred to as a phase frequency detector or a phase detector. The phase comparator is configured to compare the phase of a first electrical signal with the phase of a second electrical signal and to output the resulting phase difference therebetween as an output signal.

[0021] In particular, in the case of a pulsed electrical signal, the phase comparator is advantageously configured to generate an "up" signal and a "down" signal from an input first electrical pulse (first electrical signal) and an input second electrical pulse (second electrical signal), depending on which pulse is detected first.

[0022] The phase comparator preferably comprises a first input, a second input, a first, particularly clock-edge-controlled, D flip-flop (DFF), a second, particularly clock-edge-controlled D flip-flop (DFF), and an AND gate. Each D flip-flop comprises a D input (set input), a Q output, a reset input ("reset"), and a clock input. The D input of each D flip-flop has a high level. The first input is connected to the clock input of the first D flip-flop and the first input of the AND gate, and the second input is connected to the clock input of the second D flip-flop and the second input of the AND gate. The reset input of the first D flip-flop and the reset input of the second D flip-flop are connected to the output of the AND gate. The Q output of the first D flip-flop is connected to the Q output of the second D flip-flop by a subtractor. The clock input of the first D flip-flop and / or the clock input of the second D flip-flop are advantageously not inverted. In particular, each of the above-mentioned connections, preferably each connection, is a direct connection, i.e. in particular, no further elements are arranged between the elements interconnected in each case.

[0023] The loop filter is preferably formed as an integrator configured to integrate the output signal of the phase comparator and in particular convert it into a DC voltage. The greater the phase shift of the electrical signals (first electrical signal and second electrical signal) input to the phase comparator, the higher the DC voltage generated by the loop filter for the subsequent drivable oscillator. Alternatively, the loop filter can advantageously be an arrangement consisting of an RC element or a charge pump and a capacitor. The topology of the loop filter does not depend on the type of drivable oscillator used. An RC element is understood to mean a circuit consisting of one or more ohmic resistors and one or more capacitors.

[0024] The drivable oscillator may preferably be a voltage controlled oscillator.

[0025] Alternatively, the drivable oscillator may preferably comprise an adjustable piezoelectric oscillating crystal having a trimmer capacitor configured to trim the piezoelectric oscillating crystal to a frequency that is based on the light transit time in the waveguide of the first signal path, meaning that the loop filter drives the trimmer capacitor, which sets the oscillation frequency of the piezoelectric oscillating crystal to a frequency that corresponds to the light transit time in the first waveguide.

[0026] For this purpose, the length of the waveguide of the first signal path and the oscillation frequency of the piezoelectric oscillating crystal are pre-matched. This matching is preferably performed at a predetermined temperature (also referred to as the target temperature). On the side of the waveguide of the first signal path, this can be done by measuring the length of the waveguide relative to the speed of light, so that, for example, the time it takes for an optical pulse to pass through the waveguide corresponds to the reciprocal of the planned oscillation frequency. At the same time, the cut of the piezoelectric oscillating crystal is measured so that the oscillation frequency (main frequency) at which the piezoelectric oscillating crystal oscillates corresponds to the planned value or substantially to the planned value. In other words, the piezoelectric oscillating crystal is cut so that it spontaneously oscillates at the same frequency as specified by the waveguide of the first signal path. For example, if the waveguide of the first signal path is configured to provide a frequency of 10 MHz for the first optical signal, the piezoelectric oscillating crystal is cut so that the oscillation frequency (main frequency) of the piezoelectric oscillating crystal is also 10 MHz.

[0027] The piezoelectric vibrating crystal is preferably a tourmaline crystal, although other piezoelectric vibrating crystals can also be used in combination with the trimmer capacitor, for example a quartz crystal can also be used here.

[0028] It is even more advantageous if the trimmer capacitor can change the oscillation frequency of the piezoelectric oscillating crystal within the oscillation frequency range so that, in the event of a temperature change, the piezoelectric oscillating crystal still oscillates at a frequency resulting from the light's transit time in the waveguide. This means that, for example, a temperature change of 5°C can cause a frequency change of 80 Hz in a tourmaline crystal configured as a piezoelectric oscillating crystal. However, due to the control loop, the entire arrangement always oscillates in the same way, or the frequency changes with temperature, but in a different way than the frequency of the tourmaline crystal. It is particularly advantageous if the control loop allows the trimmer capacitor to always reduce the tourmaline crystal to the frequency specified by the waveguide of the first signal path, so that the tourmaline crystal is correspondingly controllable and allows for an 80 Hz change.

[0029] The trimmer capacitor may preferably be a varactor.

[0030] Advantageously, the control device can be implemented as hardware and / or software, i.e., the control device can be implemented entirely as hardware or software, or partly as hardware and partly as software.

[0031] The optoelectric converter device preferably includes a first optoelectric converter and a second optoelectric converter. In this case, the first signal path advantageously includes the first optoelectric converter, and the second signal path advantageously includes the second optoelectric converter. The first optoelectric converter is configured to generate a first electrical signal based on a first optical clock signal, and the second optoelectric converter is configured to generate a second electrical signal based on a second optical clock signal. An embodiment of the time measurement device including two optoelectric converters has the advantage that the first electrical signal and the second electrical signal can be easily generated separately from each other. Advantageously, the first optoelectric converter is configured identically to the second optoelectric converter. In other words, the first optoelectric converter and the second optoelectric converter are preferably configured identically. This ensures that the response time of the first optoelectric converter is the same as the response time of the second optoelectric converter. As a result, it is possible to ensure that the signal delay caused by the first optoelectric converter and the signal delay caused by the second optoelectric converter are the same in magnitude. Furthermore, this makes it possible to ensure that the light transit time in the waveguide of the first signal path is exclusively frequency-determining, since said signal delays are mutually cancelled out by the control device.

[0032] Alternatively, the optoelectronic converter device may comprise a single optoelectronic converter. The optoelectronic converter device may be advantageously configured to convert the first clock optical signal into a first electrical signal and the second clock optical signal into a second electrical signal. To this end, the optoelectronic converter device may comprise a signal divider configured to receive two optical signals from the two signal paths as a superimposed signal and to generate a first electrical signal and a second electrical signal from the superimposed signal. In this variant, the first signal path may advantageously comprise a first waveguide, an optical divider of the electro-optical converter device, a single optoelectronic converter, and a first signal divider signal path of the signal divider. The second signal path may advantageously comprise a single optoelectronic converter and a second signal divider signal path of the signal divider. In this case, the optical divider preferably comprises a semitransparent mirror. Furthermore, in this case, the first waveguide of the first signal path may preferably be a single waveguide of the time measurement device.

[0033] According to a first advantageous embodiment of the present invention, the electro-optical converter device comprises only a single electro-optical converter and one optical splitter. The single electro-optical converter is configured to generate an optical clock signal based on a control signal, and the optical splitter is configured to split the optical clock signal into a first optical clock signal and a second optical clock signal. By providing the electro-optical converter device with a single electro-optical converter, it is possible to provide a time measurement device that generates the first optical clock signal and the second optical clock signal with relatively low energy consumption. The optical splitter can preferably comprise a partially transparent mirror, in particular a partially transparent concave mirror.

[0034] According to a second advantageous embodiment of the present invention, the electro-optical converter is a first electro-optical converter, and the electro-optical converter device further comprises a second electro-optical converter. In other words, the electro-optical converter device of the second advantageous embodiment comprises two electro-optical converters. Both electro-optical converters are driven by a single control signal, thereby generating optical signals, preferably of identical frequency and phase. In this case, the first electro-optical converter is configured to generate a first optical clock signal, and the second electro-optical converter is configured to generate a second optical clock signal. By designing the electro-optical converter device with two electro-optical converters, the first and second optical signals can be generated without significant technical expenditure. Furthermore, since the two optical signals are generated independently of each other, the quality of the first and second optical signals is guaranteed. Furthermore, the intensities of the two optical signals can be set separately. Providing two electro-optical converters is particularly advantageous in time measurement devices where a sufficient power supply can be ensured.

[0035] According to an advantageous embodiment of the present invention, the second optoelectronic converter can be arranged immediately adjacent to the electro-optical converter device. In particular, the second optoelectronic converter can be directly connected to the electro-optical converter device. In another advantageous embodiment of the present invention, the second waveguide of the second signal path can extend parallel to the first waveguide of the first signal path. As a result, the electro-optical converter device, in particular the second electro-optical converter, is connected to the electro-optical converter device via the second waveguide. In this case, the second waveguide is preferably shorter than the first waveguide, in particular much shorter than the first waveguide. The first waveguide is preferably at least three times, preferably at least ten times, more preferably at least 30 times longer than the length of the second waveguide. Note that the location of the second waveguide does not depend on whether the electro-optical converter device includes a single electro-optical converter or two electro-optical converters.

[0036] In the time measuring device according to the invention, the waveguide can be provided in an electro-optical converter device comprising a first signal path and one or two electro-optical converters, or in an electro-optical converter device comprising a first signal path, a second optical signal path and one or two electro-optical converters. The decision whether to provide only one waveguide (the waveguide of the first signal path) or two and / or one or two electro-optical converters depends on the functional purpose or on certain predetermined parameters of the time measuring device, such as the maximum power consumption.

[0037] For better understanding, it should be further noted that in an electro-optical converter device comprising a single electro-optical converter, the first and second optical clock signals initially represent one single optical signal, specifically the aforementioned clock optical signal. Said signal is generated and emitted by the single electro-optical converter and then split into two signal paths, namely the first and second signal paths, by splitting with an optical splitter. In this case, the first signal path is preferably understood to be frequency-determining. In contrast to the second signal path, the first signal path can comprise a waveguide (first waveguide), while the second signal path can be led directly into the electro-optical converter device. Alternatively, the second signal path can also comprise a waveguide (second waveguide), which is preferably shorter than the waveguide of the first signal path. In this case, the first optical signal passes through a longer waveguide (first waveguide) on the first signal path, and the second optical signal passes through a shorter waveguide (second waveguide) on the second signal path. This means that the transit time of the first optical signal is longer than that of the second optical signal. Since both optical signals reach the control device, particularly the phase comparator, after passing through their respective waveguides and after conversion into corresponding electrical signals, the optical signal referred to as the "first clock optical signal" arrives later than the optical signal referred to as the "second clock optical signal." Therefore, from a time point of view, the optical signal referred to as the "first clock optical signal" is actually the second signal, and the optical signal referred to as the "second clock optical signal" is actually the first signal when it reaches the control device, particularly the phase comparator.

[0038] If the time measurement device comprises a first waveguide and a second waveguide, the first waveguide and the second waveguide are preferably configured so that, at a predetermined temperature (target temperature), the transit time of the first clock optical signal in the first waveguide and the transit time of the second clock optical signal in the second waveguide are different from each other. Furthermore, the first waveguide and the second waveguide are preferably configured so that the change in the transit time of the first clock optical signal in the first waveguide for a predetermined temperature deviation from the predetermined temperature is the same as the change in the transit time of the second clock optical signal in the second waveguide for the same predetermined temperature deviation (from the predetermined temperature). In other words, the first waveguide and the second waveguide are preferably configured so that, for any temperature change, they exhibit exactly the same change in the transit duration of each optical signal through the corresponding waveguide. For example, if the temperature rises 5°C from a given temperature, and the time it takes for a first optical clock signal to travel through a first waveguide increases by "n1" nanoseconds due to the temperature increase, the transit time of the second optical clock signal through the second waveguide will also increase by "n1" nanoseconds for the same temperature increase. If the temperature drops, for example, 2°C, and the first optical clock signal travels through the first waveguide faster by "n2" nanoseconds, the transit time of the second optical clock signal through the second waveguide will also decrease by "n2" nanoseconds.

[0039] This embodiment of the time measuring device not only eliminates the signal delay caused by the electro-optical and opto-electrical converter devices from the determination of the clock frequency of the time measuring device, as described above, but also compensates for temperature deviations from a predetermined temperature that affect the light transit time in the first waveguide, thus ensuring the accuracy of the time measuring device even in the event of temperature deviations from the predetermined temperature.

[0040] It should be noted that the proposed temperature compensation may result in a more accurate clock for the time measurement device than temperature compensation that measures the current temperature using a temperature sensor and adjusts a pulse counter (binary counter) based on the temperature deviation between the current temperature and a predetermined temperature. This is because it is not always possible to guarantee that the temperature sensor accurately detects the temperature of each waveguide, especially the first waveguide, and / or the temperature surrounding each waveguide, especially the first waveguide. Furthermore, the temperature measurement itself may be affected by the changed temperature, making it impossible to correctly adjust the pulse counter. Therefore, downstream electronic compensation by the pulse counter, which compensates for frequency changes based on temperature changes, may be subject to errors. For these reasons, temperature compensation on the waveguide side is more accurate.

[0041] Because the control device always accurately reproduces the frequency resulting from the time difference, or phase difference, between the first and second electrical signals, the frequency always remains the same, regardless of any temperature changes and the resulting time delays of each waveguide. This is because, in each case, the time delay of the first waveguide resulting from temperature changes is exactly the same as the time delay of the other waveguide. The difference between the two is always the same. Therefore, the frequency of the control signal output by the control device, and in particular the drivable oscillator, is always the same, regardless of any temperature changes.

[0042] It should be noted that the temperature around the respective waveguide and / or the temperature of the respective waveguide may be understood as temperature. The predetermined temperature corresponds in particular to the temperature at which the first waveguide is configured to enable a reference frequency to be achieved for the clock of the time measurement device. The predetermined temperature may in particular be 25°C. It should be noted that the temperature deviation is the temperature difference between the current temperature and the predetermined temperature. It should further be noted that in this case it is not necessary to measure the current temperature.

[0043] The main factors causing the change in the transit time of light in the waveguides in the event of a temperature change, in this case the first and second waveguides in the event of a temperature deviation from a predetermined temperature, are the longitudinal stretching of the waveguides as seen from the respective expansion coefficients and the change in the speed of light due to the change in the refractive index in the respective waveguides. Thus, by purposefully selecting or setting the expansion coefficients and / or refractive index of the first and / or second waveguides, it is possible to achieve the same change in the transit time of light in the first and second waveguides in the event of a temperature deviation from a predetermined temperature.

[0044] In this respect, the first and second waveguides differ from one another in particular in terms of the material through which the optical signal passes and / or the length and / or the cross-sectional design, where the second waveguide is in particular shorter than the first waveguide. By selecting the material through which the light passes and / or the length and / or the cross-sectional design of the first and / or second waveguides, the expansion coefficients and / or the refractive index of said waveguides can be set.

[0045] The coefficient of expansion of the first and / or second waveguide is preferably 0.41x10 -6 K -1 ~8x10 -6 K -1 It can be between.

[0046] In particular, the ratio between the expansion coefficient of the first waveguide and the expansion coefficient of the second waveguide can be between 1:30 and 1:4, in particular 1:16.

[0047] According to an advantageous embodiment of the invention, the first waveguide is configured as a hollow-core fiber and the second waveguide is configured as a solid-core fiber. In particular, the second waveguide can be a single-mode fiber or a multimode fiber. In this case, the ratio of the expansion coefficients of the first and second waveguides is preferably 1:16.

[0048] As already explained, the response of the transit time of light through a waveguide to temperature changes is determined not only by the change in the length of the waveguide but also by the change in the refractive index of the optical waveguide material. Thus, for example, a change in the speed of light through pure glass will result in a much larger time delay than a longitudinal stretch of the waveguide due to the changed refractive index. In contrast, the change in the refractive index of air with temperature changes is very small. This results in a very large difference between the response of a hollow-core fiber to temperature changes and that of a solid-core fiber, i.e., a single-mode fiber or a multimode fiber, for example.

[0049] Because hollow-core fibers are typically made from pure silica glass that is not doped with germanium, while solid-core fibers are typically doped with germanium, the difference in expansion coefficient between the two fiber types is significant (the expansion coefficient for hollow-core fibers is approximately 0.41x10). -6 whereas the expansion coefficient of a solid-core fiber is about 8x10 -6 Because both the expansion coefficient and the change in refractive index cause the transit time of light through the waveguide to increase with increasing temperature, and because both the expansion and the change in refractive index have a much larger effect in solid-core fibers than in hollow-core fibers, there is a very large difference in the transit time change with temperature for the two fiber types.

[0050] This allows the control device, especially the phase comparator, to match the first and second waveguides. Ultimately, the difference between the two waveguides is the frequency-determining optical waveguide. However, since the length of the waveguides is crucial to the accuracy of the time measurement device, the second waveguide should be as short as possible and the first waveguide as long as possible. To achieve this, the ratio of their responses to temperature changes should be as large as possible, since the ratio of the lengths of the two waveguides should be proportional to the ratio of their responses to temperature changes.

[0051] Furthermore, to simplify this temperature compensation method, we note that the response to temperature changes (due to longitudinal stretching and refractive index changes) should be linear for both fiber types.

[0052] Temperature compensation on the waveguide side is also possible by heating the first and / or second waveguides in such a way that if a drop in the current temperature is detected, a change in the temperature of the first and / or second waveguides, and thus a change in the light transit time in the respective waveguides, is prevented. However, heating the first and / or second waveguides can be very complicated and consume a lot of power, and furthermore, there is a risk that the heating devices used for this purpose are not absolutely perfect and therefore may cause certain inaccuracies in the time measurement device itself.

[0053] Preferably, a reflector is disposed at the reflecting end of the first signal path waveguide (first waveguide), allowing the first optical clock signal to be reflected back into the first signal path waveguide. In this case, the first signal path is configured so that the reflected first optical clock signal can be output to a first optoelectronic converter at the supply end of the first signal path waveguide. Therefore, for a given length of the first signal path waveguide, the path the light must travel before being acquired by the optoelectronic converter device is doubled. This allows the desired reference frequency for the time measurement device clock to be achieved with a more compact design of the time measurement device. Furthermore, this results in a reduction in the cost of the first signal path waveguide, and therefore the time measurement device. This is particularly advantageous from the perspective of the accuracy of the time measurement device, when the first signal path waveguide is configured as a hollow-core fiber, because hollow-core fiber is very difficult to manufacture or provide. For example, a 20-meter-long hollow-core fiber would account for more than 95% of the total cost of the time measurement device. Therefore, by providing a reflector at the reflective end of the waveguide of the first signal path, the cost of the time measurement device can be reduced by approximately 50%.

[0054] The reflector is preferably configured as a concave mirror. In this case, the concave mirror is advantageously configured to recollimate the divergent light emerging from the waveguide. In particular, the concave mirror can be a spherical concave mirror. However, the reflector can also be any other type of mirror, particularly suitable for reflecting the optical signal emerging at the reflecting end. According to another advantageous embodiment of the invention, the reflector can be configured as a plane mirror arranged directly above the reflecting end, i.e., the corresponding output of the corresponding waveguide. For this purpose, an end cap can be advantageously arranged directly above the reflecting end of the waveguide, and the inner surface of this end cap, i.e., the surface of the end cap facing the reflecting end of the waveguide, is mirrored. This ensures that little or no light is lost after reflection. An embodiment of the invention with a mirrored end cap has the further advantage that separate components and associated adjustments can be omitted, for example, when a separate end cap is arranged at the reflecting end in addition to the concave mirror.

[0055] The first signal path preferably comprises an optical splitter at a feed end of the waveguide, the splitter configured to output the reflected first optical clock signal into the first optical-to-electrical converter, the optical splitter preferably comprising a semi-transparent mirror or a fiber splitter.

[0056] Preferably, the electro-optical converter device can further comprise a lens between the light splitter and the electro-optical converter. The lens is particularly configured to refract the light emitted by the electro-optical converter so that the light propagates in a parallel direction. For this purpose, a focusing lens can be advantageously used. In this case, the focus of the focusing lens is advantageously located at the point from which the light generated by the electro-optical converter is emitted. However, the lens can also be configured to collect the divergent light emitted by the electro-optical converter and to focus the light in particular at the center of the first waveguide.

[0057] In the context of the present invention, a lens may advantageously comprise an optical system comprising a single lens element or at least two lens elements.

[0058] Preferably, each electro-optical converter of the electro-optical converter device comprises a semiconductor laser or a light-emitting diode. That is, in the above-described embodiment of the time measuring device, the single electro-optical converter or the first electro-optical converter and / or the second electro-optical converter of the electro-optical converter device each comprise a semiconductor laser or a light-emitting diode. The semiconductor laser may in particular be a pigtailed semiconductor laser. Correspondingly, the light-emitting diode may be a pigtailed light-emitting diode.

[0059] Preferably, each optical-to-electrical converter comprises a photodiode configured to convert a corresponding optical clock signal into a corresponding electrical signal.

[0060] In the context of the present invention, the useful signal generator may also be referred to as an electronic useful signal generator.

[0061] To generate the above-mentioned useful signal, the useful signal generator can preferably comprise a pulse counter (binary counter). In this case, the pulse generator is preferably configured to count the control signal. In this case, the useful signal generator is preferably configured to generate the useful signal when the count value of the control signal is equal to a predetermined count value. The predetermined count value is preferably set to a frequency based on the light transit time in the waveguide of the first signal path.

[0062] Alternatively, to generate the above-mentioned useful signal, the useful signal generating device can advantageously include a frequency divider. The frequency divider is configured to divide the frequency of the control signal. In this case, the useful signal preferably corresponds to the output signal of the frequency divider. In this case, the frequency of the control signal can particularly correspond to a multiple of 2, in particular a power of 2, for example 524288 Hz or 1048576 Hz. In this case, the frequency of the control signal can advantageously be resolved by the frequency divider into other frequencies, such as 1 Hz or 8 Hz. In the case of a time measuring device configured as a clock, for example, the resolved frequency corresponds to the useful signal on which the clock display device displays the time. It should be noted that in the case of a useful signal with a frequency of, for example, 8 Hz, the jumps of the second hand of a mechanical clock display device occur eight times per second, and are no longer perceived as "jumps" by the observer.

[0063] A combination of a frequency divider and a pulse counter is also possible to generate the useful signal. In this case, the frequency divider is preferably arranged before the pulse counter in terms of the signal. Advantageously, the frequency of the control signal can be halved in a first step, particularly multiple times, to achieve an intermediate frequency. In a second step, the intermediate frequency can be set to the desired or useful frequency by the pulse counter. In this case, the useful signal generator is preferably configured to generate the useful signal when the count value of the output signal of the frequency divider is equal to a predetermined count value. In this case, the predetermined count value is preferably set based on the intermediate frequency achieved by the frequency divider. The technique of halving the frequency of the oscillating crystal in a first step, particularly multiple times to achieve an intermediate frequency, and then counting down the intermediate frequency to the desired frequency in a second step is particularly advantageous for time measurement devices in which the control signal has a high frequency, for example, 8.88 MHz or 10 MHz. In this way, power can be saved compared to simply counting down the frequency of the control signal.

[0064] If the control signal is analog, the useful signal generating device preferably comprises a device for converting the analog control signal into a digital signal.

[0065] According to an advantageous embodiment of the time measuring device configured as a clock, the clock display is a mechanical clock display. In this case, the clock preferably comprises a drive that can move the mechanical clock display. In this case, the drive can advantageously be driven by a useful signal. In particular, the clock display can comprise an hour hand and / or a minute hand and / or a second hand.

[0066] Advantageously, the timepiece can further comprise a clockwork. In this case, the drive device is configured to drive the clockwork. The timepiece display device is connected to the clockwork and can be driven by the clockwork. The clockwork preferably comprises at least an hour indicator and / or a minute indicator and / or a second indicator, and / or a third wheel.

[0067] The drive is preferably configured as a stepper motor.

[0068] According to an advantageous embodiment of the time measuring device configured as a clock, the clock display is an electronic clock display configured to display the time on the basis of the useful signal.

[0069] Furthermore, the time measuring device preferably comprises a power supply device configured to supply power to the electro-optical converter device and / or the control device and / or the useful signal generating device and / or the drive device and / or the clock display device when the time measuring device is configured as a clock, and / or the clock display device when configured as an electronic clock display device.

[0070] The power supply device may preferably comprise at least one battery. The at least one battery may preferably be charged by the energy harvesting device. The energy harvesting device may preferably comprise at least one thermoelectric generator and / or at least one solar cell. The thermoelectric generator may in particular comprise one or more thermoelectric elements.

[0071] It should be noted that in the context of the present invention, the first signal path waveguide may also be referred to as the first waveguide, even if the time measurement device comprises only a single waveguide called the first signal path waveguide.

[0072] Further details, advantages and features of the invention will become apparent from the following description of embodiments with reference to the accompanying drawings, in which identical or functionally identical components are in each case designated with the same reference signs. [Brief explanation of the drawings]

[0073] [Figure 1] FIG. 1 is a simplified schematic diagram of a time measurement device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a simplified schematic diagram of an area of ​​a time measurement device according to a first embodiment. [Figure 3] FIG. 3 is a circuit diagram of a phase comparator of the time measurement device according to the first embodiment. [Figure 4] FIG. 4 is a flow diagram of the phase comparator of FIG. [Figure 5] FIG. 5 is a simplified schematic diagram of an area of ​​a time measurement device according to a second embodiment of the invention. [Figure 6] FIG. 6 is a simplified schematic diagram of an area of ​​a time measurement device according to a third embodiment of the invention. [Figure 7] FIG. 7 is a simplified schematic diagram of an area of ​​a time measurement device according to a fourth embodiment of the invention. [Figure 8] FIG. 8 is a simplified schematic diagram of an area of ​​a time measurement device according to a fifth embodiment of the invention. [Figure 9] FIG. 9 is a simplified schematic diagram of an area of ​​a time measurement device according to a sixth embodiment of the invention. [Figure 10] FIG. 10 is a simplified schematic diagram of an area of ​​a time measurement device according to a seventh embodiment of the invention. [Figure 11] FIG. 11 is a simplified schematic diagram of an area of ​​a time measurement device according to an eighth embodiment of the present invention. [Figure 12]FIG. 12 is a simplified schematic diagram of an area of ​​a time measurement device according to a ninth embodiment of the present invention. [Figure 13] FIG. 13 is a simplified schematic diagram of an area of ​​a time measurement device according to a tenth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0074] A time measurement device 100 according to a first embodiment of the present invention will be described in detail below with reference to FIGS.

[0075] As is apparent from Figure 1, the time measuring device 100 is configured as a timepiece, in particular a wristwatch, and therefore comprises two connections 140 for wristbands 160. However, the time measuring device 100 can also be a wall clock, a floor clock, a table clock or any other kind of table clock.

[0076] The time measuring device 100 further comprises a watch case 110, a timepiece crystal 150 arranged therein, a dial 120, a wheel 170, and three hands 130 for displaying the hours, minutes, and seconds. The hands 130 are part of a mechanical timepiece display 106 for displaying the time of day.

[0077] Furthermore, the time measuring device 100 comprises a timing generator assembly 101, a clockwork 105 and a drive unit 104 for driving the clockwork 105. The drive unit 104 is particularly configured as a stepper motor. The clockwork 105 is connected to a mechanical clock display 106 so as to move hands 130 of the clock display 106. In particular, the clockwork 105 comprises at least an hour indicator, a minute indicator and a second indicator, each of which is connected to one of the hands 130.

[0078] The timing generator assembly 101 is configured to determine a frequency associated with the clock of the time measurement device 100. Part of the timing generator assembly 101 is a useful signal generator 103 configured to generate a useful signal for clocking time based on the frequency of a control signal. To this end, the useful signal generator 103 may comprise a pulse counter. If the control signal is an analog signal, a device may be provided in the useful signal generator 103 for converting the analog control signal into a digital (pulsed) signal.

[0079] The drive unit 104 is driven based on the useful signal and drives the clockwork 105 .

[0080] 2, it can be seen that the time measurement device 100 further comprises an electro-optical converter device 1, an opto-electrical converter device 2, a first signal path 3, a second signal path 4, and a control unit 5. These components are part of a timing generator assembly 101 and form an oscillation system 102. In this embodiment, the opto-electrical converter device 2 comprises a first opto-electrical converter 21 and a second opto-electrical converter 22. The first opto-electrical converter 21 and / or the second opto-electrical converter 22 may each comprise a photodiode.

[0081] The first signal path 3 includes a waveguide (first waveguide) 61, and extends from the electro-optical converter device 1 to the opto-electrical converter device 2 via the waveguide 61. As a result, the first signal path 3 includes a first opto-electrical converter 21 in addition to the waveguide 61. The second signal path 4 extends from the electro-optical converter device 1 to the opto-electrical converter device 2, and therefore includes a second opto-electrical converter 22. Therefore, the first signal path 3 and the second signal path 4 each include the opto-electrical converter device 2 as a part thereof.

[0082] The electro-optical converter device 1 is configured to provide a first optical clock signal into a first signal path 3, in particular a waveguide 61, and a second optical clock signal into a second signal path 4. To this end, the electro-optical converter device 1 comprises a single electro-optical converter 10 and an optical splitter 13. The electro-optical converter 10, which may in particular comprise a semiconductor laser or a light-emitting diode, is configured to generate the optical clock signal. In this case, the optical splitter 13 is configured to split the optical clock signal that may be generated by the electro-optical converter 10 into a first optical clock signal and a second optical clock signal.

[0083] The optical-electrical converter device 2 can generate a first electrical signal based on a first clock optical signal and generate a second electrical signal based on a second clock optical signal. In particular, the first optical-electrical converter 21 is configured to generate the first electrical signal, and the second optical-electrical converter 22 is configured to generate the second electrical signal.

[0084] The first and second opto-electrical converters 21 and 22 are advantageously configured identically. In other words, the two opto-electrical converters 21, 22 are structurally identical, and the signal delay caused by the first opto-electrical converter 21 is the same as the signal delay caused by the second opto-electrical converter 22. In this case, the second opto-electrical converter 22 is arranged immediately after the electro-optical converter device 1, in particular the optical splitter 13. In particular, the second opto-electrical converter 22 is directly connected to the optical splitter 13. It should be noted at this point that in this embodiment, for the sake of illustration, the direct connection between the second opto-electrical converter 22 and the optical splitter 13 is shown by a line.

[0085] Therefore, the first signal path 3 and the second signal path 4 are configured such that the transit time of the first clock optical signal in the first signal path 3 differs from the transit time of the second clock optical signal in the second signal path 4. In particular, due to the structurally identical opto-electrical converters 21, 22, the transit time of the first clock optical signal in the first signal path 3 differs from the transit time of the second clock optical signal in the second signal path 4 by the transit time of the first clock optical signal in the waveguide 61.

[0086] However, according to a variant of the first embodiment, it is also possible to configure the first optical-to-electrical converter 21 and the second optical-to-electrical converter 22 differently and / or to connect the electro-optical converter 10 to the second optical-to-electrical converter 22 via a waveguide. In the latter case, the waveguide is part of the second signal path 4. In this case, the waveguide of the second signal path 4 is shorter, in particular much shorter, than the waveguide 61 of the first signal path 3. In this case, the waveguide 61 of the first signal path 3 is preferably at least 10 times, preferably at least 30 times, longer than the waveguide of the second signal path 4. In this embodiment, the waveguide 61 of the first signal path 3 can be referred to as the first waveguide, and the waveguide of the second signal path 4 can be referred to as the second waveguide.

[0087] The control device 5 is configured to generate the above-mentioned control signal based on the phase difference between the first electrical signal and the second electrical signal, generate a useful signal by the useful signal generating device 103 based on the frequency of this control signal, and control the electrical-optical converter device 1 by the useful signal to generate two optical signals.

[0088] In particular, it is provided that for the two signal paths 3, 4, two optical signals (first and second optical signals) with the same frequency and no phase shift are generated in the electro-optical converter device 1 based on the control signal. The two optical signals differ in phase shift only due to the difference in transit time in the two signal paths 3, 4.

[0089] For this purpose, the control device 5 includes a phase comparator 50 , a loop filter 51 for integrating the output signal of the phase comparator 50 , and an oscillator 52 that can be driven by the output signal of the loop filter 51 .

[0090] The phase comparator 50 has a first input 501 and a second input 502. The first input 501 is configured to receive a first electrical signal, and the second input 502 is configured to receive a second electrical signal. To this end, the first input 501 is connected to the first optical-to-electrical converter 21, and the second input 502 is connected to the second optical-to-electrical converter 22. The phase comparator 50 is configured to compare the phase of the first electrical signal with the phase of the second electrical signal and to output the resulting phase difference therebetween as an output signal. The exact design and mode of operation of the phase comparator 50 will be explained in more detail below with reference to Figures 3 and 4.

[0091] The loop filter 51 is advantageously formed as an integrator arranged to integrate the output signal of the phase comparator 50 and convert it into a DC voltage. Alternatively, an arrangement consisting of an RC element or a charge pump and a capacitor can be used as the loop filter 51. The greater the difference between the time duration of the input first electrical signal and the time duration of the input second electrical signal, the higher the DC voltage generated by the loop filter 51 for the subsequent drivable oscillator 52.

[0092] The drivable oscillator 52 is configured as a voltage-controlled oscillator (VCO). Alternatively, the drivable oscillator 52 can comprise a tunable piezoelectric oscillating crystal with a trimmer capacitor. In this case, the trimmer capacitor can be configured as a varactor. Preferably, a tourmaline crystal can be used as the piezoelectric oscillating crystal.

[0093] The output signal of the drivable oscillator 52 corresponds to or at least is based on a control signal for controlling the electro-optical converter device 1 , in particular the electro-optical converter 10 .

[0094] Depending on the application or embodiment of the time measurement device 100, the control device 5 can be implemented as hardware and / or software, i.e., components of the control device 5 are implemented exclusively as software or hardware, or the control device 5 is configured as a combination of hardware and software.

[0095] To supply power to the electro-optical converter device 1, the control device 5, the useful signal generating device 103 and the driving device 104, the time measuring device 100 comprises a power supply device.

[0096] The power supply device may comprise at least one battery, which may preferably be charged by at least one thermoelectric generator and / or an energy harvesting device comprising at least a solar cell.

[0097] A control loop, in particular a phase-locked loop, is formed by the electro-optical converter device 1, the first signal path 3, the second signal path 4, the photoelectric converter device 2, and the controller 5, which is signal-connected to the electro-optical converter device 1. That is, the above-described oscillation system 102 is configured as a control loop, in particular a phase-locked loop.

[0098] The control loop couples the frequency of the control signal with which the electro-optical converter 10 is clocked, thereby making it possible to freeze the frequency of the oscillating system 102 at a constant value. In particular, the control loop couples the output signal of the drivable oscillator 52 to the input signal of the phase comparator 50, thereby ensuring a constant and always identical frequency of the oscillating system 102, which serves as the starting point for the clock of the time measuring device 100.

[0099] 3 is a circuit diagram showing the exact design of phase comparator 50. FIG.

[0100] From FIG. 3 it can be seen that the phase comparator 50 comprises a first input 501, a second input 502, a first, in particular a clock edge controlled D flip-flop (DFF) 53, a second, in particular a clock edge controlled D flip-flop (DFF) 54 and an AND gate 55.

[0101] The first D flip-flop 53 has a D input (set input) 531, a Q output 534, a reset input 533 ("reset"), and a non-inverting clock input 532. Correspondingly, the second D flip-flop 54 has a D input (set input) 541, a Q output 544, a reset input 543 ("reset"), and a non-inverting clock input 542. The clock inputs 532 and 542 each respond only to positive (rising) signal edges.

[0102] A high level is present at the D input 531 of the first D flip-flop 53. A first input 501 of the phase comparator 50 is connected to the clock input 532 of the first D flip-flop 53 and to a first input 551 of an AND gate 55, and a second input 502 of the phase comparator 50 is connected to the clock input 542 of the second D flip-flop 54 and to a second input 552 of the AND gate 55. A reset input 533 of the first D flip-flop 53 and a reset input 543 of the second D flip-flop 54 are connected to an output 553 of the AND gate 55. A Q output 534 of the first D flip-flop 53 is connected to a Q output 544 of the second D flip-flop 54 by a subtractor 56. Notably, the described connections are direct, i.e., without any further components connected between the respective interconnected components.

[0103] The label "REF" in the circuit diagram of FIG. 3 represents a "reference signal" corresponding to the first electrical signal. The label "VCO" stands for "voltage controlled oscillator" and indicates a VCO signal corresponding to the second electrical signal. The label "PD" stands for "phase difference" and corresponds to the output signal of the phase comparator 50. "reset" indicates a reset signal, "up" represents an up signal, and "down" represents a down signal. The up signal corresponds to the output signal of the first D flip-flop 53, and the down signal corresponds to the output signal of the second D flip-flop 54.

[0104] The mode of operation of the phase comparator 50 is explained below with reference to the flow diagram of FIG.

[0105] For the first rising edge of the VCO signal (second electrical signal), the second (lower) D flip-flop 54 captures the high level at its D input 541 and sets the Q output 544 of the second D flip-flop 54 to a high level, resulting in the Down signal going "high" (arrow 201).

[0106] After an optical delay time in the waveguide 61 of the first signal path 3, a rising edge appears at the first input 501, also called the REF input, of the phase comparator 50, causing the first (upper) D flip-flop 53 to also receive a high level from its D input 531 and set the up signal to "high" at its Q output 534 (arrow 202).

[0107] In contrast to a conventional phase comparator 50 in which a flip-flop is reset when both output signals of the flip-flops are "high," in the phase comparator 50 of Figure 3, the first D flip-flop 53 and the second D flip-flop 54 are reset when both input signals to the phase comparator 50, i.e., the VCO signal and the REF signal, are "high." However, the VCO signal goes "low" again before the rising edge of the REF signal reaches the phase comparator 50.

[0108] Therefore, the two D flip-flops 53, 54 are reset only after the next edge of the VCO signal goes "high" again. At this point, the REF signal is also still "high" and a reset signal is generated (arrow 203).

[0109] The down signal (arrow 204) and the up signal (arrow 205) are reset by the reset signal. The first down pulse is longer than the up pulse, resulting in only one incorrect signal reaching the loop filter 51 following the phase comparator 50. However, due to the large time constant of the control, a single incorrect pulse is not significant.

[0110] The modified reset is followed by a rising edge at the first input 501 (REF input) of the phase comparator 50, causing the up signal to go "high" (arrow 206).

[0111] The subsequent rising edge of the VCO signal also temporarily sets the DOWN signal to a "high" level (arrow 207). Because both the REF signal and the VCO signal, i.e., both inputs of AND gate 55, are now "high" (arrow 208), a RESET signal appears at output 553 of AND gate 55, resetting both the DOWN signal (arrow 209) and the UP signal (arrow 210).

[0112] The up signal is high for a longer period of time than the down signal, resulting in an increase in the frequency of the drivable oscillator 52. This is repeated in the same manner on subsequent cycles until the drivable oscillator 52 is engaged at the desired frequency.

[0113] The described circuitry ensures proper temporal reordering of the input electrical signals, specifically the first and second electrical signals, generated by the two optoelectronic converters 21, 22. The phase comparator 50 thus allows the control loop to be engaged at a self-generated frequency. The described circuitry of the phase comparator 50 is particularly advantageous when the period T=1 / f of the VCO signal at the start (after turning on) is greater than the transit time of the first electrical signal through the waveguide 61 of the first signal path 3. A conventional phase comparator can also be used for the phase comparator 50 if the period T=1 / f of the VCO signal at the start (after turning on) is not greater than the transit time of the first electrical signal through the waveguide 61 of the first signal path 3.

[0114] The proposed time measuring device 100 configured as a clock has the advantage, in particular, that the oscillating system 102 is free from delays caused by electronic components and that the frequency of the oscillating system 102 associated with the clock of the time measuring device 100 depends in principle, in particular exclusively, on the duration of the travel of the first clock optical signal through the waveguide 61 of the first signal path 3 or on the speed of light in the waveguide 61 of the first signal path 3 and the length of the waveguide 61.

[0115] FIG. 5 relates to a time measuring device 100 configured as a clock according to a second embodiment of the invention.

[0116] The time measurement device 100 according to the second embodiment differs from the time measurement device 100 according to the first embodiment by the following design of the oscillation system 102 .

[0117] In this case, the first signal path 3 comprises a first waveguide 61, and the second signal path 4 comprises a second waveguide 62. That is, the electro-optical converter device 1 is connected to the first opto-electrical converter 21 via the first waveguide 61 and to the second opto-electrical converter 22 via the second waveguide 62. In particular, in contrast to the time measuring device 100 according to the first embodiment, in which there is a direct connection between the optical splitter 13 of the electro-optical converter device 1 and the second opto-electrical converter 22, the second opto-electrical converter 22 is connected to the optical splitter 13 of the electro-optical converter device 1 via the second waveguide 62. The first waveguide 61 and the second waveguide 62 can in particular extend parallel to each other.

[0118] The first waveguide 61 and the second waveguide 62 are configured such that, at a predetermined temperature, the transit time of the first optical clock signal in the first waveguide 61 and the transit time of the second optical clock signal in the second waveguide 62 are different from each other.

[0119] Furthermore, the first waveguide 61 and the second waveguide 62 are configured such that the change in transit time of the first clock optical signal in the first waveguide 61 for a given temperature deviation from a given temperature is the same as the change in transit time of the second clock optical signal in the second waveguide 62 for the same given temperature deviation. This means that if the transit time of the first clock optical signal increases by 'n' nanoseconds due to a temperature change, for example, the second waveguide 62 is configured such that the transit time of the second clock optical signal in the second waveguide 62 also increases by 'n' nanoseconds for the same temperature change.

[0120] For this purpose, the first waveguide 61 and the second waveguide 62 can differ in terms of the material through which light can pass and / or the length and / or cross-sectional design. In this case, the second waveguide 62 is shorter than the first waveguide 61. In this case, the first waveguide 61 is preferably at least 10 times, preferably at least 30 times, the length of the waveguide of the second waveguide 62.

[0121] In particular, the first waveguide 61 can be configured as a hollow-core fiber, and the second waveguide 62 can be configured as a solid-core fiber. In this case, the second waveguide 62 can be a single-mode fiber or a multimode fiber. In this case, the ratio of the expansion coefficient of the first waveguide 61 to the expansion coefficient of the second waveguide 62 can be between 1:30 and 1:4, in particular 1:16.

[0122] The time measuring device 100 according to the second embodiment configured as a clock has the advantage that it can compensate for temperature changes of the first waveguide 61, which in particular result in changes in the original length and refractive index of the first waveguide 61. In particular, this makes it possible to dispense with a temperature sensor and a readjustment of the frequency setting for the pulse counter of the useful signal generating device 103, so that measurement inaccuracies can be eliminated.

[0123] FIG. 6 relates to a time measuring device 100 configured as a clock according to a third embodiment of the invention.

[0124] The time measurement device 100 according to the third embodiment differs from the time measurement device 100 according to the first embodiment by the following design of the oscillation system 102 .

[0125] In this case, the electro-optical converter device 1 comprises a first electro-optical converter 11 and a second electro-optical converter 12. The first electro-optical converter 11 is configured to generate a first optical clock signal, and the second electro-optical converter 12 is configured to generate a second optical clock signal. The first electro-optical converter 11 can be configured as a semiconductor laser or a light-emitting diode. The same applies to the second electro-optical converter 12. In contrast to the first embodiment, since two electro-optical converters 11, 12 are provided, the electro-optical converter device 1 does not comprise an optical splitter.

[0126] In particular, the first electro-optical converter 11 is configured to provide a first clock optical signal in the first signal path 3, and the second electro-optical converter 12 is configured to provide a second clock optical signal in the second signal path 4. The first signal path 3 includes a first waveguide 61. The second signal path 4 comprises a second waveguide 62 connecting the second electro-optical converter 12 to the second opto-electrical converter 22. The second waveguide 62 is not required because this design does not involve temperature compensation and only involves the elimination of electronic processing time. The second signal path 4 could also directly connect the second electro-optical converter 12 to the second opto-electrical converter 22.

[0127] In this embodiment of the time measuring device 100 , both the first electro-optical converter 11 and the second electro-optical converter 12 are controlled by a control signal which may be generated by the control device 5 .

[0128] As already explained, the provision of two electro-optical converters allows the elimination of an optical splitter, thereby simplifying the design of the oscillator system 102 and thus reducing the expenditure in manufacturing the overall time measurement device 100. Furthermore, the first and second optical clock signals can be easily generated independently of each other.

[0129] FIG. 7 relates to a time measuring device 100 configured as a clock according to a fourth embodiment of the invention.

[0130] The time measurement device 100 according to the fourth embodiment differs from the time measurement device 100 according to the third embodiment by the following design of the oscillation system 102 .

[0131] The first signal path 3 comprises a first waveguide 61, and the second signal path 4 comprises a second waveguide 62. The first waveguide 61 and the second waveguide 62 are configured such that, on the one hand, at a predetermined temperature, the transit time of the first clock optical signal in the first waveguide 61 and the transit time of the second clock optical signal in the second waveguide 62 are different from each other, and, on the other hand, the first waveguide 61 and the second waveguide 62 are configured such that the change in the transit time of the first clock optical signal in the first waveguide 61 for a predetermined temperature deviation from the predetermined temperature is the same as the change in the transit time of the second clock optical signal in the second waveguide 62 for the same predetermined temperature deviation.

[0132] For this purpose, it is possible to appropriately select a material and / or a length and / or a cross-sectional design through which light can pass of the first waveguide 61 and / or the second waveguide 62. In this case, the second waveguide 62 is shorter than the first waveguide 61. In this case, the first waveguide 61 is preferably at least three times, preferably at least ten times, more preferably at least 30 times as long as the length of the second waveguide 62.

[0133] In particular, the first waveguide 61 can be configured as a hollow-core fiber and the second waveguide 62 can be configured as a solid-core fiber, in particular a single-mode fiber or a multimode fiber, in which case the ratio of the expansion coefficient of the first waveguide 61 to the expansion coefficient of the second waveguide 62 can be between 1:30 and 1:4, in particular 1:16.

[0134] The time measurement device 100 according to the fourth embodiment has the advantage that it can compensate for temperature changes of the first waveguide 61, which cause changes in the original length and refractive index of the first waveguide 61. In particular, this makes it possible to omit a temperature sensor, and as a result, measurement inaccuracies can be eliminated.

[0135] FIG. 8 relates to a time measuring device 100 configured as a clock according to a fifth embodiment of the invention.

[0136] The time measuring device 100 according to the fifth embodiment differs from that according to the third or fourth embodiment essentially by the design of the region of the oscillator system 102 comprising the first signal path 3 .

[0137] As can be seen from FIG. 8, the electro-optical converter device 1 includes, in addition to the first electro-optical converter 11, a lens 14 disposed after the first electro-optical converter 11 in the direction from the first electro-optical converter 11 to the first waveguide 61. The lens 14 is configured as a convex lens and serves to refract light emitted in different directions from the first electro-optical converter 11 so that the light beam is collimated after the lens 14. In other words, the lens 14 is configured to collimate the divergent light of the first electro-optical converter 11. In FIG. 8, the lens 14 is shown as a single lens element. However, it is also possible to configure the lens 14 as an optical system including at least two lens elements.

[0138] At a first end of the first waveguide 61, which in the context of the present invention is referred to as the feed end 611, an optical splitter 6 is arranged. In particular, the optical splitter 6 is arranged between the first waveguide 61 and the lens 14. In this case, the optical splitter 6 is configured as a fiber splitter.

[0139] A reflector 7 is disposed at a second end of the first waveguide 61, which in the context of the present invention is referred to as the reflecting end 612. Light that is fed into the first waveguide 61 at the feeding end 611 and emerges from the first waveguide 61 at the reflecting end 612 can be reflected back into the first waveguide 61 by the reflector 7.

[0140] For this purpose, in particular a concave mirror can be used as reflector 7. In this case, the concave mirror is configured to recollimate the divergent light emerging from first waveguide 61. In particular, the concave mirror can be a spherical concave mirror. However, it is also possible for reflector 7 to be any other type of mirror that is particularly suitable for reflecting the light beam emerging from reflecting end 612.

[0141] In this embodiment, the first signal path 3 comprises a first waveguide 61 , an optical splitter 6 , a reflector 7 and a first optical-to-electrical converter 21 .

[0142] In the direction from the first electro-optical converter 11 to the first waveguide 61, particularly the supply end 611 of the first waveguide 61, the optical splitter 6 is configured to pass the first optical signal, and in the direction from the first waveguide 61, particularly the reflection end 612 of the first waveguide 61, to the first electro-optical converter 11, the optical splitter 6 is configured to output the reflected first optical signal 6 into the first optical-electrical converter 21.

[0143] During operation of the time measurement device 100, the first electro-optical converter 11 supplies a first optical clock signal into the first waveguide 61 via the lens 14 and the optical splitter 6. The first optical signal is reflected into the first waveguide 61 by the reflector 7 at the reflecting end 612 and output by the optical splitter 6 into the first optical-to-electrical converter 21. That is, the optical splitter 6 itself acts on the reflected first optical clock signal, in other words, as light passes through the first waveguide 61 in the direction from the reflector 7 to the optical splitter 6.

[0144] The first optical-to-electrical converter 21 converts the first optical signal into a first electrical signal, which is transmitted to the phase comparator 50 of the control device 5, in particular to the first input 501 of the phase comparator 50, as already mentioned above.

[0145] The time measurement device 100 according to the fifth embodiment offers the advantage that in this case the optical path, i.e. the path travelled by the first clock optical signal within the first waveguide 61, is twice the length of the first waveguide 61. Thus, the length of the first waveguide 61 remains the same, while the optical path of the first optical signal can be doubled, which can increase the accuracy of the clock of the time measurement device 100. Alternatively, the optical path of the first optical signal can remain the same, while the length of the first waveguide 61 can be halved, which can save space within the time measurement device 100 and halve the investment, i.e. expenditure, on the first waveguide 61.

[0146] FIG. 9 relates to a time measuring device 100 configured as a clock according to a sixth embodiment of the invention.

[0147] The time measuring device 100 according to the sixth embodiment differs from that according to the fifth embodiment essentially in the design of the first electro-optical converter 11 .

[0148] In this case, the first electro-optical converter 11 is configured as a pigtailed semiconductor laser or a pigtailed light-emitting diode. As a result, in the case of the time measurement device 100 according to the sixth embodiment, the lens 14 provided in the time measurement device 100 according to the fifth embodiment can be omitted.

[0149] FIG. 10 relates to a time measuring device 100 configured as a clock according to a seventh embodiment of the invention.

[0150] The time measuring device 100 according to the seventh embodiment differs from that according to the fifth embodiment essentially by the design of the region of the oscillator system 102 comprising the first signal path 3 in particular.

[0151] In the time measurement device 100 according to the seventh embodiment, the supply lens 8 is attached directly to the supply end 611 of the first waveguide 61. The supply lens 8 is configured to collimate the light entering the first waveguide 61.

[0152] The optical splitter 6 is arranged between the supply lens 8 and the lens 14. In particular, the optical splitter 6 is configured as a partially transparent mirror and serves to output the reflected first clock optical signal into the first opto-electrical converter 21. That is, in the direction from the first waveguide 61, in particular from the supply end 611 of the first waveguide 61, to the first electro-optical converter 11, the optical splitter 6 is configured to output the reflected first clock optical signal into the first opto-electrical converter 21. The output of the first clock optical signal reflected by the reflector 7 is achieved by the optical signal being reflected by the partially transparent mirror to the first opto-electrical converter 21. In the direction from the first electro-optical converter 11 to the first waveguide 61, in particular from the supply end 611 of the first waveguide 61, the optical splitter 6 passes the first optical signal generated by the first electro-optical converter 11.

[0153] During operation of the time measurement device 100 , a first optical signal generated by the first electro-optical converter 11 is fed into the first waveguide 61 via the lens 14 , the optical splitter 6 and the feed lens 8 .

[0154] At the reflecting end 612 of the first waveguide 61, the first optical signal is reflected by the reflector 7 back into the first waveguide 61 and fed into the first opto-electrical converter 21 via the feed lens 8 and the optical splitter 6. The first opto-electrical converter 21 converts the first optical signal into an electrical signal, which is then directed to the first input 501 of the phase comparator 50 of the control device 5.

[0155] FIG. 11 relates to a time measuring device 100 configured as a clock according to an eighth embodiment of the invention.

[0156] The time measurement device 100 according to the eighth embodiment essentially differs from the seventh embodiment in that in this case the optoelectrical converter device 2 comprises a single electro-optical converter 10, and the time measurement device 100 comprises a single waveguide 61 and an optical splitter 13 for splitting the optical clock signal generated by the electro-optical converter 10 into a first optical clock signal and a second optical clock signal. Furthermore, the optical splitter 13 is configured to output the first optical clock signal reflected by the reflector 7 into the first optoelectric converter 21. That is, the optical splitter 13 has two functions: a splitting function and an output function.

[0157] The light splitter 13 is particularly configured as a partially transparent mirror and is arranged between the supply lens 8 and the lens 14. Furthermore, the second opto-electrical converter 22 is arranged so that the portion of the light generated by the single electro-optical converter 10 that is reflected by the partially transparent mirror that functions as the light splitter 13 is fed into the second opto-electrical converter 22.

[0158] In this case, in the context of the present invention, the optical splitter 13 can be understood in particular as part of the electro-optical converter device 1. The light that reflects from the partially transparent mirror and reaches the second optical-to-electrical converter 22 corresponds to the second optical clock signal. Therefore, the second signal path 4 comprises the second optical-to-electrical converter 22. The first signal path 3 comprises the supply lens 8, the single waveguide 61, the reflector 7, the optical splitter 13 and the first optical-to-electrical converter 21. The light that passes through the partially transparent mirror corresponds to the first optical clock signal.

[0159] FIG. 12 relates to a time measuring device 100 configured as a clock according to a ninth embodiment of the invention.

[0160] The time measurement device 100 comprises a single electro-optical converter 10, an optical splitter 13 forming an electro-optical converter device 1, an optical-electrical converter device 2 comprising a single electro-optical converter 20 and a signal splitter 23, a single waveguide 61, a reflector 7 and a supply window 9.

[0161] The reflector 7 is arranged directly above the reflecting end 612 of the waveguide 61 and is advantageously configured as a plane mirror. For this purpose, an end cap can advantageously be arranged directly on the reflecting end 612 of the waveguide 61, with the inner surface of this end cap, i.e. the surface of the end cap facing the reflecting end 612 of the waveguide 61, being mirrored. This ensures that little or no light is lost after reflection.

[0162] The feed window 9 is located directly at the feed end 611 of the waveguide 61. An end cap configured to admit light can be used as the feed window 9. In this case, the light splitter 13 can be configured as a partially transparent mirror, particularly a partially transparent concave mirror, and can be arranged after the electro-optical converter 10 in the direction from the electro-optical converter 10 to the waveguide 61. Thus, a first portion of the light emitted from the electro-optical converter 10 is reflected and collimated by the partially transparent concave mirror and fed into the waveguide 61 through the feed window 9. The partially transparent concave mirror can also be referred to as a semi-transparent focusing mirror. This portion of the light corresponds to the first optical clock signal. A second portion of the light emitted from the electro-optical converter 10 passes through the semi-transparent mirror and is fed into the opto-electrical converter 20. The second portion of the light corresponds to the second optical clock signal. As can be seen in FIG. 12, the concave surface of the partially transparent concave mirror faces the electro-optical converter 10.

[0163] The first optical clock signal and the second optical signal are acquired by the optoelectronic converter 20 at different times because the two optical signals travel paths of different lengths and are therefore time-shifted. The optoelectronic converter device 20 generates a first electrical signal based on the first optical clock signal and a second electrical signal based on the second optical clock signal. The first electrical signal and the second electrical signal are also time-shifted signals. During operation of the time measurement device 100, the first optical clock signal and the second optical clock signal form a superimposed signal. Therefore, in other words, the optoelectronic converter 20 is configured to generate a superimposed signal formed from the first optical clock signal and the second optical clock signal.

[0164] However, in order to be able to distinguish the two electrical signals from each other due to the fact that both the first and second electrical signals are generated by the same opto-electrical converter 20, the above-mentioned signal splitter 23 is provided. In particular, the signal splitter 23 is configured to split or separate the first and second electrical signals from each other so that said signals can be directed to the control device 5, in particular to the first input 501 and the second input 502 of the phase comparator 50, respectively. In other words, the signal splitter 23 is configured to generate the first and second electrical signals from the superimposed signal.

[0165] In this case, the first signal path 3 comprises a waveguide 61, a reflector 7, an optical splitter 13 of the electro-optical converter device 1, a single optical-electrical converter 20, and a first signal splitter signal path 231, and the second signal path 4 comprises a single optical-electrical converter 20 and a second signal splitter signal path 232.

[0166] The time measuring device 100 according to the ninth embodiment has the advantage in particular that only a single waveguide, a single electro-optical converter and a single opto-electrical converter are required.

[0167] FIG. 13 relates to a time measuring device 100 configured as a clock according to a tenth embodiment of the invention.

[0168] The time measurement device 100 according to the tenth embodiment differs from that according to the ninth embodiment in that in this case the opto-electrical converter device 2 comprises a first opto-electrical converter 21 for generating a first electrical signal based on a first optical clock signal and a second opto-electrical converter 22 for generating a second electrical signal based on a second optical clock signal.

[0169] It will be understood that the optical splitter 13, configured as a partially transparent mirror, in particular a partially transparent concave mirror, is arranged with respect to the single waveguide 61 so that a portion of the optical signal generated by the single electro-optical converter 10 is reflected by the partially transparent mirror and fed into the waveguide 61, the portion corresponding to the first optical clock signal. As can be seen from FIG. 12 , the concave surface of the partially transparent concave mirror faces the electro-optical converter 10. Furthermore, the partially transparent mirror, the first opto-electrical converter 21, and the second opto-electrical converter 22 are arranged with respect to each other so that the first optical clock signal reflected by the reflector 7 reaches the first opto-electrical converter 21, and the portion of the optical signal generated by the single electro-optical converter 10 passes through the partially transparent mirror and corresponds to the second optical clock signal reaches the second opto-electrical converter 22.

[0170] To prevent a portion of the first optical clock signal from reaching the second opto-electrical converter 22 and a portion of the second optical clock signal from reaching the first opto-electrical converter 21, a separator 24 is advantageously arranged between the first opto-electrical converter 21 and the second opto-electrical converter 22. The separator 24 may in particular be part of the opto-electrical converter device 2. Advantageously, the separator 24 may be configured as a dividing wall.

[0171] In this case, the first signal path 3 comprises a waveguide 61, a reflector 7, an optical splitter 13 of the electro-optical converter device 1 and a first optical-electrical converter 21, and the second signal path 4 comprises a second optical-electrical converter 22.

[0172] It should be noted that in the described embodiment, as mentioned above, a concave or a plane mirror can be used as reflector 7. In particular, when reflector 7 is configured as a plane mirror, it is particularly advantageous to arrange it directly at the reflective end 612 of first waveguide 61.

[0173] Although the time measuring device 100 according to the described embodiment is configured as a clock, the invention can also be used in other fields of application. For example, the above-described time measuring device 100 can be used in a navigation device without the drive unit 104, the clockwork 105 and the mechanical clock display 106. Alternatively, this type of time measuring device 100, also referred to in the context of the invention as a navigation device time measuring device, can preferably comprise an application-oriented unit. In particular, the application-oriented unit can be a positioning unit configured to determine the position of the navigation device based on the useful signal generated by the useful signal generating device 103. The application-oriented unit can be implemented as software and / or hardware.

[0174] In addition to the above description of the invention, for supplementary disclosure thereof, explicit reference is made to exemplary representations of the invention in FIGS. [Explanation of symbols]

[0175] 1. Electro-optical converter device 2. Photoelectric converter device 3 First signal path 4 Second signal path 5. Control device 6 light splitter 7 Reflector 8. Lens supply 9 Supply Window 10. Electro-optical converter 11 First electro-optical converter 12 Second electro-optical converter 13 Light splitter 14 Lenses 20 Photoelectric converter 21 First photoelectric converter 22 Second photoelectric converter 23 Signal splitter 24 Separator 50 phase comparator 51 Loop Filter 52 Drivable Oscillators 53 First D Flip-Flop 54 Second D Flip-Flop 55 AND Gate 56 Subtractor 61 First waveguide 62 Second Waveguide 100-hour measurement device 101 Timing Generator Assembly 102 Oscillation System 103 Useful signal generation device 104 Drive unit 105 Clockwork 106 Clock display device 110 Watch Case 120 dial 130 needles 140 Connection 150 Timepiece Glass 160 wristbands 170 wheels 201 Arrow 202 Arrow 203 Arrow 204 Arrow 205 Arrow 206 Arrow 207 Arrow 208 Arrow 209 Arrow 210 Arrow 231 first signal divider signal path 232 second signal divider signal path 501 First Input 502 Second Input 531 D Input 532 clock input 533 Reset Input 534 Q output 541 D Input 542 Clock Input 544 Q output 551 First Input 552 Second Input 611 Supply end 612 Reflection end

Claims

1. A clock (100), an electro-optical converter device (1) having at least one electro-optical converter (10; 11, 12); a photoelectric converter device (2); a first signal path (3) leading into the photoelectric converter device (2) via a first waveguide (61); a second signal path (4) into the photoelectric converter device (2) either directly or via a second waveguide (62); A control device (5); a useful signal generating device (103), the electro-optical converter device (1) is configured to provide a first optical clock signal into the first waveguide (61) and a second optical clock signal into the second signal path (4); the photoelectric converter device (2) is configured to generate a first electrical signal based on the first optical clock signal and to generate a second electrical signal based on the second optical clock signal; the first signal path (3) and the second signal path (4) are configured such that a transit time of the first optical clock signal in the first signal path (3) and a transit time of the second optical clock signal in the second signal path (4) are different from each other; the control device (5) is configured to generate a control signal based on a phase difference between the first electrical signal and the second electrical signal, and to drive the electro-optical converter device (1) with the control signal to generate the two optical signals; the useful signal generator (103) is configured to generate a useful signal for clocking time based on the frequency of the control signal; the clock comprises a clock display (106) for displaying the time based on the useful signal; clock.

2. A wristwatch, an electro-optical converter device (1) having at least one electro-optical converter (10; 11, 12); a photoelectric converter device (2); a first signal path (3) leading into the photoelectric converter device (2) via a first waveguide (61); a second signal path (4) into the photoelectric converter device (2) either directly or via a second waveguide (62); A control device (5); a useful signal generating device (103), the electro-optical converter device (1) is configured to provide a first optical clock signal into the first waveguide (61) and a second optical clock signal into the second signal path (4); the photoelectric converter device (2) is configured to generate a first electrical signal based on the first optical clock signal and to generate a second electrical signal based on the second optical clock signal; the first signal path (3) and the second signal path (4) are configured such that a transit time of the first optical clock signal in the first signal path (3) and a transit time of the second optical clock signal in the second signal path (4) are different from each other; the control device (5) is configured to generate a control signal based on a phase difference between the first electrical signal and the second electrical signal, and to drive the electro-optical converter device (1) with the control signal to generate the two optical signals; the useful signal generator (103) is configured to generate a useful signal for clocking time based on the frequency of the control signal; the wristwatch comprises a clock display (106) for displaying the time based on the useful signal; watch.

3. 3. The timepiece (100) according to claim 1 or 2, wherein the control device (5) comprises a phase comparator (50), a loop filter (51) for integrating the output signal of the phase comparator (50), and an oscillator (52) that can be driven by the output signal of the loop filter.

4. 4. The timepiece (100) of claim 3, wherein the drivable oscillator (52) is a voltage controlled oscillator or comprises a tunable piezoelectric oscillating crystal with a trimmer capacitor.

5. 3. The watch (100) according to claim 1 or 2, wherein the control device (5) is implemented as hardware and / or software.

6. 3. The timepiece (100) of claim 1 or 2, wherein the electro-optical converter device (1) comprises a single electro-optical converter (10) configured to generate a clock optical signal and an optical divider (13) configured to divide the clock optical signal into the first clock optical signal and the second clock optical signal.

7. 3. A timepiece (100) according to claim 1 or 2, wherein the electro-optical converter is a first electro-optical converter (11), the electro-optical converter device (1) comprises a second electro-optical converter (12), the first electro-optical converter (11) is configured to generate the first clock optical signal, and the second electro-optical converter (12) is configured to generate the second clock optical signal.

8. 3. The watch (100) of claim 1 or 2, wherein the photoelectric converter device (2) comprises a single photoelectric converter (20) for generating a superimposed signal formed from the first optical clock signal and the second optical clock signal, and a signal divider (23) configured to generate the first electrical signal and the second electrical signal from the superimposed signal.

9. A clock (100) as described in claim 8, wherein a reflector (7) is arranged at the reflection end (612) of the first waveguide (61) so that the first clock optical signal can be reflected into the first waveguide (61) by this reflector, and the first signal path (3) is configured so that the reflected first clock optical signal can be output into the single opto-electrical converter (20) of the first signal path (3) at the supply end (611) of the first waveguide (61).

10. the photoelectric converter device (2) comprises a first photoelectric converter (21) and a second photoelectric converter (22), the first signal path (3) comprises the first photoelectric converter (21), and the second signal path (4) comprises the second photoelectric converter (22); The first optical-to-electrical converter (21) is configured to generate the first electrical signal based on the first optical clock signal, and the second optical-to-electrical converter (22) is configured to generate the second electrical signal based on the second optical clock signal. A watch (100) according to claim 1 or 2.

11. 11. A timepiece (100) according to claim 10, wherein the first photoelectric converter (21) is configured identically to the second photoelectric converter (22).

12. 3. A watch (100) according to claim 1 or 2, wherein the second waveguide (62) is shorter than the first waveguide (61).

13. The first waveguide (61) and the second waveguide (62) At a predetermined temperature, the transit time of the first optical clock signal in the first waveguide (61) and the transit time of the second optical clock signal in the second waveguide (62) are different from each other, and configured such that the change in transit time of the first optical clock signal in the first waveguide (61) for a predetermined temperature deviation from a predetermined temperature is the same as the change in transit time of the second optical clock signal in the second waveguide (62) for the same predetermined temperature deviation. A watch (100) according to claim 12.

14. 14. A watch (100) according to claim 13, wherein the first waveguide (61) and the second waveguide (62) differ in the material through which light can pass and / or in the length and / or cross-sectional design.

15. 11. The timepiece (100) of claim 10, wherein a reflector (7) is arranged at a reflection end (612) of the first waveguide (61) so that the first optical clock signal can be reflected into the first waveguide (61) by the reflector, and the first signal path (3) is configured so that the reflected first optical clock signal can be output into the first opto-electrical converter (21) of the first signal path (3) at a supply end (611) of the first waveguide (61).

16. 16. The watch (100) of claim 15, wherein the first signal path (3) comprises an optical splitter (6; 13) at the supply end (611) of the first waveguide (61), the splitter being configured to output the reflected first clock optical signal into the first optical-to-electrical converter (21).

17. 17. A timepiece (100) according to claim 16, wherein the light splitter (6; 13) comprises a partially transparent mirror or a fiber splitter.

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