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Tempe a u e and ec o bending sensing wi h a
supe mode ibe B agg g a ing
To ci e his a icle: J Villa o o
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2026
J. Phys. Pho onics
8 015015
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PAPER
Tempe a u e and ec o bending sensing wi h a supe mode ibe
B agg g a ing
J Villa o o1,2,∗, M Alonso-Mu ias3, D Maldonado-Hu ado4, A Zo noza5, F Lindne 6, J Bie lich6,
S Sales4and K Wond aczek6
1Depa amen o de Ingenie ía de Comunicaciones, Uni e si y o he Basque Coun y UPV/EHU, 48013 Bilbao, Spain
2IKERBASQUE, Basque Founda ion o Science, 48011 Bilbao, Spain
3Cen o de In es igaciones en ´
Op ica A. C., Loma del Bosque 115, Lomas del Campes e, León 37150 Guanajua o, Mexico
4Pho onics Resea ch Labs, iTEAM Resea ch Ins i u e, Uni e si a Poli ècnica de València, Camino de Ve a s/n, 46022 Valencia, Spain
5Depa men o Applied Ma hema ics, Uni e si y o he Basque Coun y UPV/EHU, 48013 Bilbao, Spain
6Leibniz Ins i u e o Pho onic Technology (Leibniz IPHT), 07745 Jena, Ge many
∗Au ho o whom any co espondence should be add essed.
E-mail: agus injoel. il[email p o ec ed]us
Keywo ds: coupled-co e ibe , mul ico e ibe s, ibe B agg g a ings, op ical ibe senso s, supe mode in e e ence, bending senso s,
empe a u e senso s
Abs ac
Due o hei mul iple ad an ages, single-mode ibe B agg g a ings (FBGs) a e widely used in a
my iad o p ac ical sensing applica ions. Howe e , hei concu en sensi i i y o s ain and em-
pe a u e makes a e e ence senso necessa y in se e al si ua ions. He e, we demons a e ha a
single supe mode FBG can be used o measu e bending and empe a u e. A specially designed wo
coupled-co e op ical ibe (TCCF) ha suppo s wo supe modes was ab ica ed in which g a -
ings we e insc ibed wi h em osecond o ul a iole lase s. The in e oga ion o he g a ings was
ca ied ou wi h a con en ional FBG senso in e oga o . I was ound ha he e lec ion spec-
um o he supe mode g a ing depended on i s insc ip ion in he TCCF. So, i was possible o
ab ica e samples in which he e lec ion spec a exhibi ed wo na ow peaks e y close o each
o he wi h well-de ined B agg wa eleng hs and e lec i i ies. C oss sensi i i ies and pola iza ion
e ec s on he de ices we e s udied. I was ound ha wo B agg wa eleng hs and wo e lec i i -
ies p o ided abundan da a o measu e bending o he TCCF, empe a u e, and o disc imina e
in which di ec ion he TCCF was ben . Thus, we belie e ha he esul s epo ed he e can pa e
he way o nex -gene a ion g a ing-based special y op ical ibe de ices ha a e capable o mul i-
pa ame e sensing. The esul s and app oaches p oposed he e can also expand he use o B agg
g a ing echnology.
1. In oduc ion
Senso s based on single-mode ibe B agg g a ings (FBGs) ha e dis inc i e ad an ages which include eli-
abili y, absolu e (wa eleng h encoded) measu emen s, immuni y o elec omagne ic in e e ence, and
mul iplexing capabili y, among o he s [1–4]. Such senso s a e comme cially a ailable and widely used in
a my iad o p ac ical applica ions.
An impo an disad an age o con en ional single-mode FBG senso s is hei concu en sensi i i y
o empe a u e and s ain. Thus, in se e al si ua ions a e e ence senso (an auxilia y B agg g a ing) o
a mechanism o compensa e o empe a u e o he e ec o en i onmen al dis u bances, may be neces-
sa y. Howe e , addi ional senso s o empe a u e compensa ion mechanisms may be imp ac ical in se -
e al applica ions whe e he e a e limi a ions in space, size, o weigh .
To ci cum en he issues men ioned abo e, he op ical ibe senso communi y has long been s i ing
o achie e mul ipa ame e sensing wi h a single de ice. Ideally, such a de ice mus be able o p o ide
simul aneous in o ma ion abou a a ge pa ame e , independen ly o along wi h o he en i onmen al
pa ame e s, mainly empe a u e. To his end, di e en complex sensing a chi ec u es o combina ions o
© 2025 The Au ho (s). Published by IOP Publishing L d
J. Phys. Pho onics 8(2026) 015015 J Villa o o e al
di e en pla o ms ha e been p oposed, see o example [5–7]. The disad an age o such mul ipa ame e
sensing pla o ms is hei elabo a e ab ica ion p ocess, which may comp omise senso ep oducibili y
and eliabili y.
An al e na i e o achie e mul ipa ame e sensing is by means o B agg g a ings insc ibed wi h a il
angle in single-mode ibe s (SMFs) [8–10]. Howe e , he in e oga ion o il ed g a ings is complex and
expensi e as i en ails pola iza ion con olle s and high spec al esolu ion o e a b oadband, a leas
60 nm [11–13]. I is he e o e complica ed o in e oga e mo e han one il ed g a ing i hey a e placed
in se ies.
B agg g a ings insc ibed in bi e ingen (pola iza ion main aining) op ical ibe s can be used o sim-
ul aneously moni o s ain and empe a u e as demons a ed in [14]. Ano he op ion o de ising mul-
ipa ame e senso s is o insc ibe g a ings in mul imode ibe (MMF) s uc u es. MMF B agg g a ings
ha e been s udied heo e ically and expe imen ally o mo e han wo decades, see o example [15,
16]. The e lec ion o MMF B agg g a ings ea u es se e al b oad e lec ion peaks ha can be se e al
nanome e s apa . Such peaks can be acked and co ela ed wi h mo e han one pa ame e [17,18].
Ne e heless, he di icul y in con olling he numbe and ype o modes ha can be exci ed in a MMF,
along wi h he ins abili y o he g a ing due o mode bea ing complica es he analysis o MMF B agg
g a ings.
He ein, we epo on he insc ip ion o B agg g a ings in an op ical ibe comp ising wo iden ical
pho osensi i e co es sepa a ed by app oxima ely 14 µm. The wo coupled co e ibe (TCCF) was
designed o allow op ical coupling be ween he co es. I was obse ed ha depending on he insc ip-
ion o he g a ing, i s e lec ion spec um exhibi ed wo na ow peaks whose wa eleng h posi ion and
e lec i i y could be co ela ed wi h empe a u e and bending. The e ec o pola iza ion and c oss sens-
i i i ies on he de ices we e s udied. I was ound ha wi h a single supe mode FBG, i was possible o
moni o TCCF bends in e ms o bo h bending di ec ion and bending angle as well as empe a u e. The
main ad an age is ha he in e oga ion o ou mul ipa ame e sensing de ice can be ca ied ou wi h a
comme cial FBG ead ou uni . Thus, he senso s based on supe mode FBGs p oposed he e can be used
in se e al p ac ical applica ions.
2. Resul s and discussion
2.1. Design and ab ica ion o he wo coupled-co e ibe
The TCCF consis s o wo ul a iole (UV) sensi i e co es embedded in a silica ma ix, whe e he o -
cen e -co e is loca ed a 14 µm om he cen al co e. Each co e o he TCCF had a nume ical ape u e
like ha o a con en ional SMF, which is 0.14 a 1550 nm.
Pho osensi i i y was ob ained using GeO2in silica. The UV sensi i e GeO2-doped silica co es we e
ab ica ed using he modi ied chemical apo deposi ion me hod. In o al, 26 GeO2-doped silica lay-
e s we e deposi ed inside a F300 silica ube o ou e diame e o 22 mm, yielding a consolida ed GeO2-
doped co e wi h a co e- o-clad diame e a io (CCDR) o 2.4; i.e. 5 mm co e and 12 mm p e o m dia-
me e . The ob ained p e o m was hen g ound and polished o achie e a CCDR o 1.6. The g ound p e-
o m was hen elonga ed o 1 mm ods. Two ods we e hen s acked oge he wi h 1 mm-diame e silica
ods as schema ically depic ed in igu e 1(a) and inse ed in o a silica cladding ube (F300) o inal ibe
p e o m. By using he so-called s ack-and-d aw me hod [19], he doped co es we e loca ed a he a ge
posi ion in he inal TCCF, igu e 1(b).
A sample o he ab ica ed TCCF was e ched o obse e he shape o he co es; such a sample was
inspec ed wi h a scanning elec on mic oscope (SEM). In igu e 1(c), i can be obse ed ha he co es
a e no pe ec ly ci cula . In he igu e, he mul i-laye s uc u e o he GeO2-doped co es is isible.
The cladding o he ibe was made o pu e silica and had a diame e o 125 µm, his means, he
same diame e and ma e ial o a con en ional SMF.
The TCCF shown in igu e 1(b) suppo s only wo supe modes. The p o ile o one o hem is
shown in igu e 2(a). The e ec on he supe mode in ensi y p o ile when he TCCF was subjec ed o a
cu a u e o 1 ×10−5m−1is shown in igu e 2(b). The esul s shown in he igu e we e calcula ed a
1550 nm wi h comme cial simula ion so wa e (MODE om Lume ical). F om igu e 2(b), i can be
no iced ha he in ensi y in he co es o he TCCF depends on he di ec ion o cu a u e.
2.2. Insc ip ion o B agg g a ings in he TCCF
The insc ip ion o B agg g a ings in he TCCF was ca ied ou by means o wo well-es ablished ech-
niques. The i s echnique in ol ed a em osecond ( s) lase equipped wi h a equency-doubled Yb-
based lase ha emi s a 515 nm and ope a es a a pulse a e o 1 kHz. This lase was ocused h ough
an oil imme sion objec i e (Plan-Apoch oma 63x/1.4 Oil M27) o c ea e pe iodic a ia ions in he
2
J. Phys. Pho onics 8(2026) 015015 J Villa o o e al
Figu e 1. (a) Pho og aph o hexagonal s ack o he p e o m wi h silica ods (whi e ods) and he wo pho osensi i e ods (high-
ligh ed in ed). (b) Mic oscopic image o a ab ica ed polyme -coa ed coupled-co e ibe . (c) SEM image o c oss sec ion o
e ched TCCF end o isualizing he GeO2-doped co es. (d) Ske ch o an SMF-TCCF +FBG s uc u e ha was subjec ed o
bending angles (θ) in he +xand −xdi ec ions. Lis he leng h o he segmen ha was ben .
Figu e 2. (a) P o ile o a supe mode suppo ed by he TCCF. (b) E ec o cu a u e o 1 ×10−5m−1on he supe mode p o ile.
All calcula ions we e done a 1550 nm wi h comme cially a ailable simula ions so wa e.
e ac i e index wi hin he co e o he TCCF. This p ocess was achie ed using a poin -by-poin insc ip-
ion echnique as epo ed in [20,21]. The second echnique in ol ed a UV lase wi h a wa eleng h o
193 nm and a phase mask [22,23]. Be o e he insc ip ion o he g a ings, app oxima ely 4 cm o TCCF
we e usion spliced o a lead-in and lead-ou segmen s o SMF. The splicing o he SMF and he TCCF
was by means o he clad alignmen me hod wi h a usion splice (model FSM-100P+ om Fujiku a).
Thus, he cen al co e o he TCCF and he unique co e o he SMF we e axially aligned. Unde hese
condi ions, he wo supe modes o he TCCF we e exci ed by he undamen al mode o he SMF. This
exci a ion is qui e e icien as he nume ical ape u es o bo h wa eguides a e he same.
The polyme coa ing o he TCCF was o ally emo ed wi h ace one. The B agg g a ings we e
insc ibed app oxima ely in he middle o he TCCF segmen . Due o he lexibili y o he insc ip ion
wi h s lase s, g a ings wi h di e en leng hs we e insc ibed in he TCCF. In addi ion, single g a ings
we e insc ibed in he cen al o he o -cen e co e. Figu es 3(a) and (b) summa ize ou esul s. I can
be no iced om hese igu es ha he e lec ion spec um o a sho s g a ing is b oade han ha o a
long one. No e also ha when he g a ing is insc ibed only in he o -cen e co e, wo B agg wa eleng hs
appea .
Ano he collec ion o g a ings, all wi h he same leng h, we e insc ibed in he TCCF wi h UV lase
and he phase mask echnique. Figu es 3(c) and (d) display he e lec ion spec a o six samples. We
obse ed e lec ion pa e ns wi h wo B agg wa eleng hs, sepa a ed app oxima ely 190 pm, in 60% o
he ab ica ed samples and one B agg wa eleng h in he es o samples. This can be a ibu ed o he
exposu e o he wo pho osensi i e co es o he UV lase pa e n. Thus, o ensu e e lec ion spec a wi h
wo B agg wa eleng hs i is impo an ha he wo pho osensi i e co es a e equally exposed o he UV
lase pa e n. This can be achie ed by o ien ing he TCCF be o e he g a ings a e insc ibed. Howe e ,
as he ab ica ion o B agg g a ings can be moni o ed in eal ime, samples ha do no ha e wo B agg
wa eleng hs can be disca ded o dual pa ame e sensing applica ions o he easons discussed in he
ollowing sec ions.
2.3. Bending and empe a u e sensing
A simple se up was implemen ed o ca y ou he bending expe imen s. The TCCF wi h B agg g a -
ing was clea ed wi h an angle o a oid F esnel e lec ion. The SMF-TCCF+FBG s uc u e was hen
placed in can ile e posi ion, see igu e 1(d). To secu e he s uc u e we used a high p ecision ibe
o a o (HFR007, om Tho labs). The dis ance om he poin whe e he s uc u e was immobilized o
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J. Phys. Pho onics 8(2026) 015015 J Villa o o e al
Figu e 3. Spec a o B agg g a ings insc ibed in he TCCF wi h a em osecond lase in he cen al co e (a) and o -cen e co e (b).
The g a ing leng hs a e indica ed. (c) and (d) Spec a o samples o 6 mm-long g a ings insc ibed in he TCCF wi h a UV lase
and phase mask.
he poin whe e i was ben , Lin igu e 1(d), was 15.30 ±0.01 mm. The bending angle o he SMF-
TCCF +FBG segmen was a ied by displacing i in s eps o 100 ±1 mic ome e s in he +xand −x
di ec ions, acco ding o he coo dina e sys em shown in igu e 1(d).
The e lec ion spec um a each bending angle was moni o ed wi h a comme cial FBG in e og-
a o (Hype ion Si155 om LUNA Inno a ions) connec ed o a lap op. An ad hoc LabVIEW p og am
was implemen ed o moni o he B agg wa eleng hs (λB) and hei e lec i i ies. The FBG in e oga o
and lap op we e con igu ed in a local a ea ne wo k ia TCP-IP p o ocol o communica e wi h each
o he . The e lec ion spec um o he SMF-TCCF +FBG s uc u e was displayed in linea scale. The
B agg wa eleng hs posi ions and hei e lec i i ies we e ound by applying he Peak De ec o VI om
LabVIEW.
Figu es 4(a) and (b) display, espec i ely, he e lec ion spec a obse ed when he TCCF was ben
a di e en angles in he +xand −xdi ec ions. No e ha he posi ions o λB1 and λB2 do no change
when he TCCF is ben ; see he e ical do ed lines in igu es 4(a) and (b). Howe e , he e lec i i y o
he wo peaks changes in opposi e manne . Figu e 4(a) shows ha R1( e lec i i y o peak loca ed a λB1)
inc eases wi h he bending angle bu R2( e lec i i y o peak loca ed a λB2) dec eases. I he di ec ion
o bending changes, R1dec eases and R2inc eases, see igu e 4(b). This means ha he TCCF bending
angle and di ec ion can be co ela ed wi h R1and R2, which a e simple o moni o .
To compensa e o possible luc ua ions o he ligh sou ce, we co ela ed he bending angle
wi h he a io o R2/R1. The ini ial o ien a ion o he TCCF co es wi h espec o he bending di ec-
ion was a bi a y. This ini ial posi ion was conside ed o be 0◦. F om his posi ion, he TCCF was
hen o a ed 30◦, 60◦, and 90◦and was ben in +xand −xdi ec ions wi h he p ocedu e desc ibed
abo e. In all cases, we collec ed he e lec ion spec a and measu ed R2and R1. The calib a ion cu es
ha we e ob ained o di e en o ien a ions o he TCCF co es wi h espec o he di ec ion o he
bending a e displayed in igu e 5. We obse ed ha a la ge angles, he beha io o he senso was
nonlinea .
F om igu e 5 he bending sensi i i ies we e calcula ed. The maximum sensi i i ies in he +xand −x
di ec ions we e ound o be, espec i ely, 0.23 and −0.279 a.u. pe deg ee. These sensi i i ies a e ∼500%
highe han hose published in [24]. F om he igu e, i can be no ed ha independen ly o he TCCF
co e o ien a ion wi h espec o he di ec ion o bending, om he a io R2/R1i is possible o quan i y
he bending deg ee and o know i he TCCF was ben o he +xo o he −xdi ec ion. No e ha in
p e ious wo k [24], his was no possible. In addi ion, in [24], ligh luc ua ions could no be com-
pensa ed o as e lec i i y changes o a single peak we e moni o ed. Mo eo e , in ou case, he posi ions
o λB1 and λB2 can be used o moni o empe a u e wi h high accu acy. Thus, sensing o empe a u e
and di ec ional bending is easible wi h a single supe mode g a ing.
To in es iga e he e ec o empe a u e on he supe mode B agg g a ing, he SMF-TCCF+FBG s uc-
u e was placed in a empe a u e calib a o (Fluke model 9103). No e ha o eal-wo ld bending meas-
u emen s, he TCCF mus be coa ed, p o ec ed o packaged. So, he analyzed empe a u e ange was
om −20 ◦C o +90 ◦C, which co e s a wide ange o en i onmen s and he empe a u e ope a ing
ange o polyme ic coa ings o op ical ibe s. The obse ed spec a and calib a ion cu e a e shown in
4
J. Phys. Pho onics 8(2026) 015015 J Villa o o e al
Figu e 4. Expe imen al e lec ion spec a obse ed when he TCCF ibe was ben di e en angles in he +xdi ec ion (a) and he
−xdi ec ion (b). In bo h g aphs, λB1,λB2,R1, and R2deno e, espec i ely, B agg wa eleng hs and e lec i i y o he peaks.
Figu e 5. Calib a ion cu es obse ed when he co es o he TCCF we e placed a di e en o ien a ions wi h espec o he x-
di ec ion ( he di ec ion o bending). The ini ial o ien a ion o he TCCF co es was deno ed as 0◦.
igu e 6. I can be no ed om he igu e ha he posi ions o he wo B agg wa eleng hs changed lin-
ea ly wi h empe a u e. The empe a u e sensi i i y, calcula ed wi h ei he o he wo B agg wa eleng hs,
was ound o be 9.9 pm ◦C−1.
The a io R2/R1as a unc ion o empe a u e is also shown in he bo om inse g aph o igu e 6. I
was obse ed ha he alue R2/R1changed app oxima ely ±1.3% in he measu ed empe a u e ange.
This alue is much lowe han hose obse ed when he TCCF was ben , which anges om 50% o
75%. Thus, empe a u e-independen bending o dual pa ame e senso s can be de eloped wi h he
s uc u e epo ed he e. In ei he case, he senso in e oga ion can be ca ied ou wi h widely a ailable
comme cial ins umen s.
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J. Phys. Pho onics 8(2026) 015015 J Villa o o e al
Figu e 6. B agg wa eleng hs as a unc ion o empe a u e. The op inse g aph shows he obse ed spec a a di e en empe a -
u es, and he bo om inse g aph shows he R2/R1 a io e sus empe a u e.
Figu e 7. Re lec ion spec a o a supe mode B agg g a ing a 40 di e en s a es o pola iza ion (SOP) o he inpu ligh . The inse
g aph shows he no malized R2/R1 a io obse ed a he 40 SOP.
Guide modes, and supe modes in pa icula , a e, in gene al, sensi i e o pola iza ion, so, he pe -
o mance o a sensing de ice based supe modes may be a ec ed by changes o pola iza ion. Thus, he
e ec o pola iza ion on he e lec ion spec a o he supe mode g a ings and on R2,R1,λB1 and λB2
was in es iga ed. To do so, an elec onic ibe pola iza ion con olle (model PC-15-1-1-2, om Phoenix
Pho onics) ha ope a es om 1300 o 1640 nm was used in he expe imen s. The con olle allowed us
o launch any s a e o pola iza ion (SOP) o he supe mode B agg g a ing. Ou indings a e launching
40 di e en SOP o he de ice a e shown in igu e 7. No e ha al hough he wo maxima and he min-
imum (dip) be ween hem change, he R2/R1 a io a ies less han 2%, see he inse g aph o igu e 7.
The changes o λB1 and λB2 ha we e obse ed we e less han 6 pm. The e o e, we can conclude ha
he supe mode B agg g a ing p oposed he e can ope a e wi h any SOP o he inpu ligh .
The ope a ion mechanism o supe mode B agg g a ings has been discussed in di e en publica ions,
see o example [24–27]. The condi ion o B agg e lec ion indica es ha speci ic wa eleng hs a e e lec-
ed and ha he in ensi y o he B agg wa eleng hs depends on he coupling coe icien o he o wa d
and backwa d p opaga ing supe modes. In gene al, wo B agg wa eleng hs (λB1 and λB2) can be expec-
ed. Howe e , ou expe imen al esul s sugges ha i depends on he insc ip ion o he B agg g a ing in
he TCCF.
P e ious wo ks ha e demons a ed ha coupled-co e ibe s a e highly sensi i e o bending [24,28].
The la e induces s ess o he ibe co es and al e s hei e ac i e indices [29]. Consequen ly, he ield
in ensi ies o he supe modes a e modi ied, hus leading o ene gy ans e be ween hem. Howe e ,
bending has no e ec on he B agg wa eleng hs. Fo hese easons, a single supe mode B agg g a ing
can be used o moni o wo pa ame e s: bending and empe a u e wi h minimal o negligible c oss
sensi i i y.
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J. Phys. Pho onics 8(2026) 015015 J Villa o o e al
3. Conclusions
In his wo k, we ha e epo ed on he ab ica ion o an op ical ibe comp ising wo iden ical pho o-
sensi i e co es sepa a ed app oxima ely 14 mic ome e s and he insc ip ion o B agg g a ing in one o in
bo h co es. I was demons a ed ha a single supe mode FBG ha has he po en ial o moni o bending
angle and di ec ion as well as empe a u e.
The in e ac ion o he g a ings wi h wo supe modes suppo ed by he wo coupled-co e ibe makes
he e lec ion spec um ha e wo well-de ined peaks ha a e close o each o he . I was obse ed ha
bending o he TCCF changed only he e lec i i y o he wo peaks and empe a u e al e ed only he
B agg wa eleng hs. The e ec o pola iza ion on he e lec ion spec a o he g a ings was s udied. Ou
esul s sugges ha pola iza ion has no signi ican e ec on he pe o mance o ou senso . In e es ingly,
he wo B agg wa eleng hs and he wo alues o e lec i i y p o ide abundan da a o measu e empe -
a u e and bending deg ee o he TCCF as well as o disc imina e in which di ec ion he TCCF was ben .
These ea u es we e obse ed a di e en o ien a ions o he co es wi h espec o he di ec ion o bend-
ing. The e o e, he posi ion o he TCCF is no ele an .
As he e lec ion o supe mode B agg g a ings has wo na ow peaks ha a e sepa a ed less han
200 pm, hei mul iplexing is s aigh o wa d. Any comme cially a ailable FBG ead ou uni can be used
o in e oga e he g a ings. The e o e, he supe mode FBGs epo ed he e can be a ac i e in applica-
ions whe e i is impo an o moni o bending deg ee and empe a u e and o disc imina e he di ec-
ion o bending o he op ical ibe wi h a single compac de ice.
Da a a ailabili y s a emen
The da a ha suppo he indings o his s udy a e a ailable upon easonable eques om he au ho s.
Acknowledgmen s
This wo k was unded in pa h ough P ojec s PDC2022-133885-I00; PID2023-152763NB-I00;
INNOFIBER PID2023-152314OB-I00, and SMARTMOORING Ce p-2022-00382, PCI2023-145987-2
unded by he Spanish MCIU/AEI /10.13039/501100011033 and he Eu opean Union Nex Gene a ion
EU/PRTR, IT11452-22 unded by he Basque Go e nmen and P2022-06 unded by he EU Ho izon2020
Ac phas 4R GA 825051. I is also pa ially suppo ed by he Cá ed a Chip Fo ónico UPV TSI-069100-
2023-0002, and PROMETEO 2021/015 Resea ch Excellency Awa d unded by he Gene ali a Valenciana.
M. Alonso-Mu ias acknowledges he suppo ecei ed om SECIHTI h ough he Na ional Pos doc o al
S ays P og am (G an No. 787628). The au ho s acknowledge Sh abya Shukla o he assis ance in some
expe imen s.
Au ho con ibu ions
J Villa o o 0000-0002-0842-9173
Concep ualiza ion (equal), Fo mal analysis (equal), In es iga ion (equal), Supe ision (equal), W i ing –
e iew & edi ing (equal)
M Alonso-Mu ias 0000-0002-5161-9562
Da a cu a ion (equal), Fo mal analysis (equal), So wa e (equal)
D Maldonado-Hu ado
In es iga ion (equal), Me hodology (equal)
A Zo noza 0000-0003-2127-6789
Da a cu a ion (equal), Fo mal analysis (equal), Me hodology (equal), So wa e (equal)
F Lindne
In es iga ion (equal), Me hodology (equal), Resou ces (equal)
J Bie lich
Fo mal analysis (equal), In es iga ion (equal), Me hodology (equal)
S Sales
Funding acquisi ion (equal), In es iga ion (equal), Resou ces (equal)
K Wond aczek 0000-0002-6268-9136
Funding acquisi ion (equal), P ojec adminis a ion (equal), Resou ces (equal), Supe ision (equal)
7
J. Phys. Pho onics 8(2026) 015015 J Villa o o e al
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