Abstract:
An apparatus for explosively removing at least one coating from a lengthwise section of an optical fiber includes: a heater for heating a heating region to above a thermal decomposition temperature of the at least one coating; a securing mechanism for securing the optical fiber so that the lengthwise section is positioned in the heating region; and a controller operatively associated with the heater. The controller is configured for: causing the heater to heat the heating region to above the thermal decomposition temperature for a sufficient duration so that the at least one coating is explosively removed from the lengthwise section of the optical fiber in the heating region; and deactivating the heater before the explosive removal of the at least one coating from the lengthwise section.

Description:
PRIORITY APPLICATION 
       [0001]    This is a continuation of U.S. patent application Ser. No. 14/609,855, filed on Jan. 30, 2015, the content of which is relied upon and incorporated herein by reference in its entirety, and the benefit of priority under 35 U.S.C. §120 is hereby claimed. 
     
    
     BACKGROUND 
       [0002]    disclosure generally relates to stripping optical fiber coatings and, more particularly, to methods and apparatus for non-contact stripping of optical fiber coatings. 
         [0003]    Optical fibers are useful in a wide variety of applications, including the telecommunications industry for voice, video, and data transmissions. In a telecommunications system that uses optical fibers, there are typically many locations where fiber optic cables that carry the optical fibers connect to equipment or other fiber optic cables. To conveniently provide these connections, fiber optic connectors are often provided on the ends of fiber optic cables. The process of terminating individual optical fibers from a fiber optic cable is referred to as “connectorization.” Connectorization can be done in a factory, resulting in a “pre-connectorized” or “pre-terminated” fiber optic cable, or in the field (e.g., using a “field-installable” fiber optic connector). 
         [0004]    Regardless of where installation occurs and the type of connector used, stripping of optical fiber coatings is typically an important step in terminating optical fibers in preparation for installing connectors. For field installations, an inherently accurate and robust coating stripping tool can be of particular importance because the technicians or operators making the installations may have varying amounts of relevant training or experience. 
         [0005]    A bare glass fiber and a 250 um coated optical fiber may appear indistinguishable to untrained eyes. Therefore, mechanical stripping can be challenging due to visibility issues. In addition, mechanical stripping may cause direct contact between tool blades and bare glass, which can cause flaws in the optical fibers and reduce their tensile strengths. Such flaws and reductions in tensile strength may be restricted through the use of non-contact stripping methods and apparatus. However, at least some of the non-contact stripping methods and apparatus are better suited for manufacturing settings rather than field settings. 
         [0006]    There is a desire for fiber stripping methods and apparatus that provide a new balance of properties. 
       SUMMARY 
       [0007]    An aspect of this disclosure is the provision of methods and apparatus for use in non-contact stripping of optical fibers. 
         [0008]    In accordance with an embodiment of this disclosure, an apparatus for explosively removing at least one coating from a lengthwise section of an optical fiber comprises: a heater configured for heating a heating region to above a thermal decomposition temperature of the at least one coating; a securing mechanism configured for securing the optical fiber so that the lengthwise section of the optical fiber is positioned in the heating region; and a controller operatively associated with the heater. The controller is configured for causing the heater to heat the heating region to above the thermal decomposition temperature of the at least one coating for a sufficient duration so that the at least one coating is explosively removed from the lengthwise section of the optical fiber in the heating region. The controller is also configured for deactivating the heater before the explosive removal of the at least one coating from the lengthwise section of the optical fiber in the heating region so that the explosive removal of the at least one coating from the lengthwise section of the optical fiber in the heating region occurs after the deactivation of the heater. The heater may be an electrical resistance heater. 
         [0009]    In accordance with another embodiment, an apparatus for explosively removing at least one coating from a lengthwise section of an optical fiber comprises a heater configured for heating a heating region to above a thermal decomposition temperature of the at least one coating to cause explosive removal of the at least one coating from the lengthwise section of the optical fiber in the heating region. The heater according to this embodiment is an electrical heater comprising a first electrical resister configured to become hot in response to electrical current passing therethrough, and a second electrical resister configured to become hot in response to electrical current passing therethrough. The heating region is positioned between the first electrical resister and the second electrical resister. In particular, the first and second electrical resisters are: a) respectively arranged in positions that are substantially radially symmetrical about an axis of the heating region; and b) are spaced apart from one another by a distance that is within a range of from about 3 times an outer diameter of the optical fiber to about 5 times the outer diameter of the optical fiber. The apparatus further comprises a securing mechanism configured for securing the optical fiber so that the lengthwise section of the optical fiber is positioned in the heating region, and a controller operatively associated with the heater. The controller is configured for deactivating the heater not later than immediately after explosive removal of the at least one coating from the lengthwise section of the optical fiber in the heating region. 
         [0010]    In accordance with another embodiment, an apparatus for explosively removing at least one coating from a lengthwise section of an optical fiber comprises: a heater configured for heating a heating region to a temperature above a thermal decomposition temperature of the at least one coating; a securing mechanism configured for securing the optical fiber so that the lengthwise section of the optical fiber is positioned in the heating region; and a controller operatively associated with the heater. The controller being configured to deactivate the heater at a predetermined time that is within a range of from about 1 millisecond after explosive removal of the at least one coating from the lengthwise section of the optical fiber in the heating region to about 500 milliseconds before explosive removal of the at least one coating from the lengthwise section of the optical fiber in the heating region. 
         [0011]    In accordance with another embodiment, a method for explosively removing at least one coating from a lengthwise section of an optical fiber comprises: a) securing the optical fiber so that the lengthwise section of the optical fiber in positioned in a heating region; and b) heating the at least one coating of the lengthwise section of the optical fiber to a temperature above a thermal decomposition temperature of the at least one coating while the lengthwise section of the optical fiber is in the heating region so that the at least one coating is exploded away from the lengthwise section of the optical fiber. The at least one coating comprises an inner coating and an outer coating, wherein the inner coating has a thermal decomposition temperature and the outer coating has a thermal decomposition temperature above the thermal decomposition temperature of the inner coating. The heating is comprised of heating the inner coating to a temperature that is above the thermal decomposition temperature of the inner coating and below the thermal decomposition temperature of the outer coating. 
         [0012]    In one example, the heating is comprised of operating a heater, and such operating includes activating the heater. The method further comprises deactivating of the heater at a predetermined time before the at least one coating is exploded away from the lengthwise section of the optical fiber in the heating region. This predetermined time may be within a range of from about 1 millisecond to about 500 milliseconds before the at least one coating is exploded away from the lengthwise section of the optical fiber. 
         [0013]    In accordance with another embodiment, a method for explosively removing at least one coating from a lengthwise section of an optical fiber comprises: a) positioning a lengthwise section of the optical fiber in a heating region, and b) exploding an elongate substantially cylindrical section of the at least one coating away from a remainder of the optical fiber. The exploding is comprised of heating the at least one coating of the lengthwise section of the optical fiber to a temperature above a thermal decomposition temperature of the at least one coating while the lengthwise section of the optical fiber is in the heating region. 
         [0014]    Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the technical field of optical communications. It is to be understood that the foregoing general description, the following detailed description, and the accompanying drawings are merely exemplary and intended to provide an overview or framework to understand the nature and character of the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments, and together with the description serve to explain principles and operation of the various embodiments. Features and attributes associated with any of the embodiments shown or described may be applied to other embodiments shown, described, or appreciated based on this disclosure. 
           [0016]      FIG. 1  is schematic perspective view of a length of unstripped optical fiber secured to an optical fiber stripping apparatus, in accordance with an embodiment of this disclosure. 
           [0017]      FIG. 2  is an isolated cross-sectional view of an example of the unstripped optical fiber of  FIG. 1 . 
           [0018]      FIG. 3A  is a top plan view of a portion of the assembly of  FIG. 1 , showing a portion of the optical fiber and a heating element of the stripping apparatus in a first state in which the heating element is unheated and the optical fiber is unstripped. 
           [0019]      FIG. 3B  is like  FIG. 3A , except for being schematically illustrative of a second state in which the heating element is heated, wherein the heating element being red hot is schematically represented by diagonal hatching. 
           [0020]      FIG. 3C  is like  FIG. 3B , except for being schematically illustrative of a third state in which a length of at least one coating of the optical fiber is stripping or separating (e.g., exploding away) from the cladding of the optical fiber, wherein the heating element being yellow-white hot is schematically represented by diagonal hatching. 
           [0021]      FIG. 3D  is like  FIG. 3A , except for being illustrative of a fourth state in which a mid span of the optical fiber has been stripped of coatings. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Various embodiments will be further clarified by examples in the description below. In general, this description relates to an optical fiber stripping apparatus  10  and methods of stripping optical fibers, wherein the stripping may comprise a heat-induced burst or explosion. 
         [0023]      FIG. 1  illustrates a stripping apparatus  10  configured so that it can be used for stripping away a length of at least one coating of an optical fiber  100 , in accordance with an embodiment of this disclosure. In the example shown in  FIG. 2 , the optical fiber  100  includes a substantially cylindrical multi-layer coating  140  comprising substantially cylindrical polymer coatings  120 ,  130 . As shown in  FIG. 1 , the stripping apparatus  10  comprises at least one heater  200 , securing mechanisms  310 ,  320  for holding the optical fiber  100  in a reproducible position, and a controller  500  for controlling the heater  200 . A sensor  400  may also be included in the stripping apparatus  10 . 
         [0024]    In one example, the heater  200  can consist of, or consist essentially of, a resistance heating metal alloy such as, but not limited to, Nichrome, so that the heater has a relatively low thermal mass as compared to ceramic materials. In addition, the heater  200  may be shaped and positioned so as to extend along and be substantially parallel to a heating region  205  through which the optical fiber  100  substantially coaxially extends. The heater  200 , heating region  205 , and optical fiber  100  may be cooperatively configured for facilitating substantially uniform heating over or along a lengthwise section (“fiber section”)  150  of the optical fiber  100 . The fiber section  150  may be positioned in close proximity to the heater  200 , so that the heater  200  can be operated to rapidly heat the coatings  120 ,  130  of the fiber section  150  by way of natural convection rather than forced convention. The coatings  120 ,  130  of the fiber section  150  may also be heated by radiative heat transfer from the heater  200 . 
         [0025]    The heater  200  may comprise at least one resistive heating element that may be in the form of a high resistance electrical wire  210  that becomes very hot in response to the flow of electrical current therethrough. The metal wire  210  can be in a bent configuration so that it includes upright sections  215  supporting linear portions or elongate sections  220 , wherein the sections  220  can function as electrical resistors and may be referred to as first and second electrical resistors, although different types of electrical resistors are within the scope of this disclosure. 
         [0026]    A majority of the wire  210  can be in the form of the elongate sections (“resistive sections”)  220  that function as electrical resistors that become hot when electrical current flows therethrough. The resistive sections  220  may be substantially parallel to one another, and they may also be arranged substantially radially symmetrically around substantially coaxial central axes of the heating region  205  and the fiber section  150 . In the embodiment shown in the drawings, when the fiber  100  is secured by the securing mechanisms  310 ,  320 , the fiber section  150  to be processed extends between, along, and is substantially parallel to the elongate resistive sections  220  of the wire  210 . The above-discussed arrangements seek to ensure that the fiber section  150  to be processed is heated substantially uniformly both radially and axially. The heater  200  may be constructed and/or arranged in any other suitable configuration for causing the fiber section  150  to be heated substantially uniformly both radially and axially. 
         [0027]    The securing mechanisms  310 ,  320  may comprise one or more supports that can be in the form of a first securing block  310  and a second securing block  320 . The fiber  100  may be secured in V-grooves  330  or other shapes of fiber groves  330  on the blocks  310 ,  320 . In addition or alternatively, clips and/or other suitable supporting and/or securing features may be included in the stripping apparatus  10  for securing the fiber  100  so that the heating region  205  and fiber section  150  are substantially coaxial. The blocks  310 ,  320  may further include protruding members or other mechanical structures extending into opposite ends of a hot zone, which may be adjacent to the heating region  205 , to shield parts of the fiber  100  from heat so as to create well-defined edges of the unstripped coatings  120 ,  130  after stripping. The securing mechanisms  310 ,  320  and associated features can be configured for keeping the fiber section  150  straight and untensioned during the stripping, which seeks to maintain the tensile strength of the fiber  100 . 
         [0028]    Referring to  FIG. 2  in greater detail, the multi-layer coating  140  of the fiber  100  can comprise a dual-layer polymer coating  120 ,  130  that extends around a glass cladding  110  and glass core  105 . The inner primary coating  120  may be configured to act as a shock absorber to minimize attenuation caused by any micro-bending of the fiber  100 . The outer secondary coating  130  may be configured to protect the primary coating  120  against mechanical damage, and to act as a barrier to lateral forces. For example, the secondary coating  130  may have a diameter of about 200 um. The multi-layer coating  140  can further include a colored, thin ink layer for identification, and this additional layer may be coated onto the outer surface of the secondary coating  130 . The outer diameter of the coated optical fiber  100  may be about 250 um. 
         [0029]    In accordance with an embodiment of this disclosure, the cladding  110  and core  105  have a higher thermal decomposition temperature than the coatings  120 ,  130 , and the primary coating  120  is softer than and has a lower thermal decomposition temperature than the secondary coating  130 . A variety of polymeric materials are suitable for use as the primary and secondary coatings  120 ,  130 . For example, the primary coating  120  may be soft UV-cured polymers, and the secondary coating  130  may be highly cross-linked UV-cured polymers. In one example, the primary coating  120  can have a thermal decomposition temperature of about 279° C., and the secondary coating  130  can have a thermal decomposition temperature of about 284° C., so that the difference in their thermal decomposition temperatures is about 100° C. 
         [0030]    With the coatings  120 ,  130  having different vaporization or thermal decomposition temperatures and the fiber section  150  positioned in the heating region  205  as discussed above, the heater  200  can be operated to rapidly heat the coatings  120 ,  130  of the fiber section  150  to a temperature that is above the thermal decomposition temperature of the primary coating  120  but below the thermal decomposition temperature of the secondary coating  130 . As a result, the primary coating  120  of the fiber section  150  can decompose into gas and cause sufficient pressure to build up inside the secondary coating  130  of the fiber section  150  for causing an explosive rupture of the region encircled by the secondary coating  130  of the fiber section  150 , without substantially damaging the cladding  110  or core  105  of the fiber  100 . 
         [0031]    In the embodiment illustrated in the drawings, the stripping apparatus  10  does not use forced convention to heat the coatings  120 ,  130  and the coatings are not heated in an inert gas environment. Rather, the stripping apparatus  10  may be configured so that the coatings  120 ,  130  are heated in the ambient atmosphere and the coatings are heated by natural convection and any associated conductive and radiant heat transfer. 
         [0032]    As shown in  FIG. 1 , the fiber section  150  can be a mid span of the optical fiber  100 . When the fiber section  150  is a mid span of the fiber  100 , the lengthwise sections of the fiber  100  immediately adjacent to the mid span fiber section  150  can function as boundary structures that at least partially contain the pressure generated by the decomposing primary coating  120  of the fiber section  150 , so that leakage of the pressure from the fiber section  150  is restricted from escaping out of ends of the fiber section  150 , so that the pressure is contained in a restricted area (e.g., contained within the region encircled by the fiber section  150 ) in a manner that seeks to provide the desired, controlled exploding and stripping of the coatings  120 ,  130  of the fiber section  150 . As a contrasting example, when the fiber section  150  is an end section of the fiber  100 , it may be the case that the pressure generated by the vaporizing primary coating  120  of the fiber section  150  escapes out the end of the fiber section  150  such that the explosion may not occur. Instead, the coatings  120 ,  130  of the fiber section  150  may decompose or burn. Alternatively, when the fiber section  150  includes or is proximate an end of the fiber  100 , the end of the fiber may be at least partially shielded, so that the end of the fiber remains cool enough to serve as a boundary for substantially containing the vapor pressure, and in response to the explosion the remaining coatings  120 ,  130  at the end of the fiber may also burst away. For example, one or more of the blocks  310 ,  320  may include protruding shielding members or other mechanical structures extending into opposite ends of the hot zone to shield an end of the fiber  100  from heat. 
         [0033]    The stripping apparatus  10  can be operated, such as under the control of the controller  500 , so that the coatings  120 ,  130  of the fiber section  150  are rapidly heated to the temperature at which the secondary coating  130  bursts (e.g., in response to the vaporization of the primary coating  120 ). This heating can comprise quickly heating the heater  200  while the heater is in close proximity to the lengthwise fiber section  150  to create a temperature field over the fiber section  150  that is substantially uniform. For example, the heater  200  can have a low thermal mass, such that after it is turned on it may be rapidly heated to above 800° C. in less than 1 second. The close proximity of the heater  200  to the lengthwise fiber section  150  can enable the heating of the coatings  120 ,  130  to a temperature beyond the burst temperature of about 400° C. in less than 1 second, causing the vaporization of the primary coating  120  and bursting away of the secondary coating  130  within about 1 second from the heater  200  being turned on. 
         [0034]    The heater  200  can be configured and operated, such as under the control of the controller  500 , so that the temperature field across the cross section of the lengthwise fiber section  150  can be substantially uniform, which can have the affect of maintaining the integrity of the secondary coating  130  until the burst temperature is reached. In contrast, an uniform temperature field can lead to decomposition of the secondary coating  130 , rendering it unable to contain sufficient vapor pressure for the desired explosion or bursting. Without the explosion process, slow decomposition and oxidation of the coating  130  may generate harmful gas. 
         [0035]    The heater  200 , or more specifically each of the elongate resistive sections  220  of the wire  210 , can have a length L ( FIGS. 3A, 3C and 3D ) of, for example, about 12 mm, so that the fiber section  150  that is substantially uniformly heated, and thus stripped by the stripping apparatus  10 , can have a length L of about 12 mm, which length L can be sufficient for many connector applications. In addition, these lengths L of the heater  200  and the fiber section  150  that is substantially uniformly heated and stripped can be longer or shorter than about 12 mm, as discussed in greater detail below. 
         [0036]    The stripping apparatus  10  can be operated so that the explosion (e.g., stripping) of the coatings  120 ,  130  occurs substantially simultaneously along the entire length L ( FIGS. 3A, 3C and 3D ) of the fiber section  150 . As examples, length L may be at least about 8 mm, at least about 10 mm, or about 12 mm or longer. For example, the length L may be within a range of from about 8 mm or about 10 mm to about 24 mm, from about 12 mm to about 24 mm, or from about 12 mm to about 20 mm. 
         [0037]    The gap between the resistive sections  220  of the wire  210  may be about 1 mm, or greater than or less than about 1 mm. As indicated above, the outer diameter of the coated optical fiber  100  may be about 250 um, so that in one example the gap between the resistive sections  220  may be about 4 times greater than the outer diameter of the optical fiber  100 . As a more general example, the gap between the resistive sections  220  may have a predetermined width that is within a range of from about 3 times the outer diameter of the coated optical fiber  100  to about 5 times the outer diameter of the coated optical fiber. 
         [0038]    The wire  210  could be otherwise configured such that it is arranged in more than two resistive sections  220 . However many resistive sections  220  are used, they may extend along and be substantially parallel to the heating region  205  and fiber section  150  in a radially symmetrical configuration that seeks to ensure uniform heating throughout the fiber section  150  to be stripped. These positional relationships between the resistive sections  220 , heating region  205  and fiber section  150  can be maintained substantially without change even when the wire  210  expands during heating. For example, in the embodiment shown in  FIG. 1 , one or more ends of the wire  210  or resistive sections  220  can be free-standing so that the wire can expand and contract along the axial directions of the resistive sections  220 , heating region  205  and fiber section  150 . In another embodiment, one or more ends of the wire  210  or resistive sections  220  can be held with spring(s) to allow the expansion of the wire  210  during heating. As one example, the wire  210  may be a 0.2 mm diameter Nichrome wire of the type used in electrically heated cigarette lighters that plug into direct current electrical sockets of automobiles. 
         [0039]    In one embodiment, the stripping apparatus  10  is automatically operative, such as under the control of the controller  500 , so that the heater  200  is deactivated or turned off shortly before, or not later than immediately after (e.g., in response to), the explosion that “strips” the coatings  120 ,  130  away from the fiber section  150 . Quickly turning off the heater  200  in this manner seeks, for example, to avoid any oxidation and burning of the unstripped sections of the coatings  120 ,  130 . 
         [0040]    The thermal mass of the heater  200  and fiber  100  may be low enough such that natural convection substantially brings down their temperatures to the ambient temperature generally rapidly, such as within about 5 seconds after the heater  200  is turned off Because the heater  200  is turned off not later than immediately after vaporization and explosion of the coatings  120 ,  130  from the fiber section  150 , and because the heater  200  cools quickly due to low thermal mass, any thermal decomposition and oxidization of the remaining edges of the coatings  120 ,  130  can be substantially eliminated without the need for a non-oxidizing gas environment. Restricting any oxidization can also preserve the tensile strength of the fiber  100 , such as by maintaining at least about 98% or over 98% of the tensile strength of the fiber  100 . Alternatively, the stripping apparatus  10  may optionally comprise a non-oxidizing gas environment. 
         [0041]    As mentioned above, the heater  200  can include or be a resistive heating element (e.g. a strip of conductive metal and/or wire  210  made of conductive metal). The controller  500  and associated features can be configured for automatically controlling the flow of electrical current through the wire  210 , for controlling the heat generated by the wire  210 . For example, the electrical current supplied to the wire  210  may be controlled by the controller  500  according to a predetermined electrical current profile. As a more specific example, the electrical current can be supplied to the wire  210  for a period of time, with a greater electrical current being supplied during the first part of that time for increasing the rate of temperature rise. Then, the electrical current may be reduced once the temperature is close to the predetermined operating temperature. However, it will be appreciated that the controller  500  may provide other suitable electrical current profiles and/or be used with other types of heaters to achieve a desired heating profile(s). 
         [0042]    As alluded to above, the stripping apparatus  10  may include at least one sensor  400 , such as a sound and/or light sensor configured for sensing the explosion or bursting of the coatings  120 ,  130  of the fiber section  150 . The explosion of the coatings  120 ,  130  may comprise a unique “pop” sound and flash of light, either of which can be used as a termination condition that is sensed by the sensor  400  and causes the sensor to send an electrical signal to the controller  500 , prompting it to deactivate or turn off the heater  200 . The sensor  400  and controller  500  may be in communication and cooperative such the heater  200  is shut off immediately by the controller  500  upon the detection of the explosive “pop” sound or the detection of emitted flash of light that are indicative of the explosion or bursting of the coatings  120 ,  130  of the fiber section  150 . For example, the sensor  400  and controller  500  may be in communication and cooperative such the heater  200  is shut off in less than 10 milliseconds, or even less than 1 millisecond, after the explosion that “strips” the coatings  120 ,  130  away from the fiber section  150 . 
         [0043]    As another example, the heater  200  can be also controlled by using an appropriate sensor  400  to optically monitor a precursor of the subject explosion, such as the onset of deformation of the coatings  120 ,  130  of the fiber section  150 , a change in the diameter of the fiber section  150 , or the like, so that the heater can be turned off prior to the explosion, which seeks to maintain the tensile strength of the fiber  100 . For example, the controller  500  may deactivate or switch off the heater  200  in response to the sensor  400  detecting deformation of the fiber section  150 , a change in the diameter of the fiber section  150 , and/or any other suitable triggers, wherein these triggers may be precursors to the subject explosion. 
         [0044]    In embodiments using an acoustic or sound sensor  400 , immunity to ambient sound interference may be improved by using filters which take into account an audio frequency signature of the explosion or bursting of the coatings  120 ,  130 . The controller  500  may be configured so that such audio signatures can be programmed thereinto. In addition, the controller  500  and at least one sensor  400  may be cooperatively configured so that acoustic, optical, and/or other types of feedback control allow stripping methods of this disclosure to accommodate different types of one or more of the coatings  120 ,  130 . 
         [0045]    In addition or alternatively, the heater  200  can be controlled without using the sensor  400 , or the sensor may be used to identify a secondary termination condition, wherein the controller  500  may be configured to turn off the heater in response to a primary termination condition that is intended to occur and normally occurs prior to the secondary termination condition. For example, the controller  500  may be configured so that the heater  200  is turned off or deactivated at a predetermined time, wherein the predetermined time may be a specific time within a range of from about 200 milliseconds to about 2 seconds after the heater is turned on or activated, the predetermined time may be a specific time within a range of from about 500 milliseconds to about 1.5 seconds after the heater is activated, the predetermined time may be about 0.9 seconds after heater is activated, the predetermined time may be about 0.95 seconds after heater is activated, the predetermined time may be about 1 second after heater is activated, and/or the predetermined time may be within a range of from about 1 millisecond to about 500 milliseconds before the explosion that “strips” the coatings  120 ,  130  away from the fiber section  150 . The selection of the predetermined time at which the controller  500  turns off the heater  200  may depend upon factors associated with the configuration of the multi-layer coating  140  and/or the configuration of the stripping apparatus  10 ; therefore, the predetermined time may be determined based upon empirical evidence. 
         [0046]    After the fiber  100  is mounted to the securing mechanisms  310 ,  320  as generally shown in  FIG. 1  and the stripping process is initiated, such as by a user operating a feature, such as a button, key, or the like, that may be provided by the controller  500 , or the user otherwise initiating the providing of the electrical current to the heater  200 , the stripping apparatus  10  may be able to strip the coatings  120 ,  130  from the fiber section  150  in less than about 2 seconds. As an example of a method operation of the stripping apparatus  10 , a sequence of operational states of the stripping apparatus  10  is shown in  FIGS. 3A-3D .  FIG. 3A  shows the heater  200  and an associated section of the secured fiber  100  before the heater  200  is switched on.  FIG. 3B  shows the heater  200  partially heated at about 0.5 seconds after electrical power is switched on for the heater  200 , wherein the wire  210  being red hot is schematically represented by diagonal hatching in the wire  210 . 
         [0047]    It may take about 1 second or less for the wire  210  to reach its maximum temperature, and the fiber coatings  120 ,  130  of the fiber section  150  may remain intact for about the first 0.8 seconds after the heater  200  is activated.  FIG. 3C  shows the heater  200  substantially fully heated at about 0.95 seconds or about 1 second after power is switched on for the heater  200 , wherein the wire  210  being yellow-white hot is schematically represented by horizontal hatching in the wire  210 . In  FIG. 3C , substantially the entirety of the coatings  120 ,  130  of the fiber section  150  are shown being exploded away from the cladding  110  of the fiber section  150 , wherein the explosion is schematically represented by stippling. This explosion may occur at about 1 second after power is switched on for the heater  200 , and the explosion may be accompanied by an audible “pop” sound and/or a flash of light that may be detected by the sensor(s)  400 . 
         [0048]    The electrical power to the heater  200  may be turned off shortly before or immediately after the explosion, such as in response to the sensor  400  sensing an audible “pop” sound and/or a flash of light that may be associated with the explosion. Thereafter, the heater  200  may be quickly cooled by the ambient environment, such as in about 5 seconds after the heater  200  has been turned off, as shown in  FIG. 3D . As shown in  FIG. 3D , the length L of the portion of the cladding  110  from which the coatings  120 ,  130  have been stripped can substantially match both the length of the heating region  205  and the length of the heated resistive sections  220 . The majority of the sections of the coatings  120 ,  130  that are stripped may bursts away from the cladding  110  substantially without generating smoke, and substantially without leaving carbon residue on the glass cladding  110 . 
         [0049]    As schematically shown in  FIG. 1 , the controller  500  may include a rechargeable battery  510  that powers the controller  500  and provides electrical current to the heater  200 . In one example, the battery  510  can be a 12 volt power supply with duty cycle and duration controls. The controller  500  may further include a switch  520  that opens and closes a circuit  530  which provides the electrical current to the heater  200 . In embodiments including an electrically powered heater  200 , such as the wire  210 , the controller  500  can turn on or switch on the heater  200  by closing the switch  520  to initiate a flow of electrical current to the heater  200 . Conversely, the controller  500  can turn off the heater  200  by opening the switch  520  to stop the flow of electrical current to the heater  200  when the termination condition is met, wherein the termination condition can be the explosion of the coatings  120 ,  130 , any suitable precursor thereto, and/or a predetermined time, such as the predetermined times discussed above. 
         [0050]    The sensor  400  and heater  200  may both be portable pluggable devices capable of being plugged into and in electrical communication with (e.g., powered by) the controller  500 . The controller  500  may be a portable handheld device that may be in some ways similar to or associated with a smartphone, or the like, and the securing mechanisms  310 ,  320  may also be portable, such that the entire stripping apparatus  10  may be portable and suitable for field use. Alternatively or in addition, the stripping apparatus  10  may also be configured for use in manufacturing settings. 
         [0051]    The controller  500  may include processing circuitry, such as processing circuitry of a computer, that is configurable to perform actions in accordance with one or more exemplary embodiments disclosed herein. In some exemplary embodiments, the processing circuitry may include a processor  550  and memory. The processing circuitry may be in communication with or otherwise control, for example, a user interface  560 , and one or more other components, features and/or modules (e.g., software modules). The user interface  560  can include a feature, such as a button, key, or the like, for being actuated by a user to initiate the stripping process. The processor may be embodied in a variety of forms. For example, the processor may be embodied as various hardware-based processing means such as a microprocessor, a coprocessor, a controller or various other computing or processing devices including integrated circuits such as, for example, an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), some combination thereof, or the like. The processor may comprise a plurality of processors. The plurality of processors may be in operative communication with each other and may be collectively configured to perform one or more functionalities of this disclosure. In some exemplary embodiments, the processor may be configured to execute instructions that may be stored in the memory or that may be otherwise accessible to the processor. As such, whether configured by hardware or by a combination of hardware and software, the processor is capable of performing operations according to various embodiments of this disclosure. 
         [0052]    In some exemplary embodiments, the memory may include one or more memory devices. The memory may include fixed and/or removable memory devices. In some embodiments, the memory may provide a non-transitory computer-readable storage medium that may store computer program instructions that may be executed by the processor. In this regard, the memory may be configured to store information, data, applications, instructions and/or the like for enabling the stripping apparatus  10  to carry out various functions in accordance with the various embodiments of this disclosure. In some embodiments, the memory may be in communication with one or more of the processor  550 , user interface  560 , and one or more other modules via bus(es) for passing information. 
         [0053]    The user interface  560  may be in communication with the processing circuitry to receive an indication of a user input at the user interface and/or to provide an audible, visual, mechanical or other output to the user. As such, the user interface may include, for example, a keyboard, a mouse, a joystick, a display, a touch screen, a microphone, a speaker, and/or other input/output mechanisms. 
         [0054]    In one embodiment, the controller  500  can include a number of different modules for selection by a user. Each module may comprise an electrical current profile defining the electrical current pulse(s) to be supplied to the heater  200  and the duration of the pulse(s) (e.g., there may be a single stage of electrical current, or there may be multiple stages of electrical currents with the same or different durations). Accordingly, the operating of the heater  200  for a predetermined time may comprise a single stage of electrical current being supplied to the heater for the predetermined time, or the operating of the heater for a predetermined time may comprise multiple stages of electrical currents being supplied to the heater during the predetermined time. For example, the controller  500  can be an open-loop controller that does not rely on the feedback from the sensor  400  regarding the explosion of the coatings  120 ,  130 . The various electrical current profiles may have some (e.g., slight) dependence on the materials of the multi-layer coating  140 , the diameters of the coatings  120 ,  130 , the inclusion of any colored ink layers for identification, and/or any other suitable factors. These factors and/or one or more other conditions can be pre-stored in modules of the controller  500  that are made available for selection by way of the user interface  560 . 
         [0055]    Variations are within the scope of this disclosure. For example, the heater  200  may comprise suitable heating elements other than or in addition to a metal wire, and the heater  200  may comprise more or less than two heated resistive sections  220 . 
         [0056]    Persons skilled in fiber stripping or optical connectivity will appreciate additional variations and modifications of the devices and methods already described. Additionally, where a method claim below does not explicitly recite a step mentioned in the description above, it should not be assumed that the step is required by the claim. Furthermore, where a method claim below does not actually recite an order to be followed by its steps or an order is otherwise not required based on the claim language, it is no way intended that any particular order be inferred. 
         [0057]    The above examples are in no way intended to limit the scope of the present invention. It will be understood by those skilled in the art that while the present disclosure has been discussed above with reference to examples of embodiments, various additions, modifications and changes can be made thereto without departing from the spirit and scope of the invention as set forth in the claims.