OP350 Handheld Optical Light Source

OP350 Handheld Optical Light Source

The ideal field equipment for mixed multimode and single-mode fiber testing

OP350 Optical Light Source

OP350 with included accessories
OP350 open with adapters
OP350 in hand


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OptoTest’s OP350 is a reliable and versatile Handheld Optical Light Source incorporating up to six mixed LED, laser, and visual fault locator (VFL) emitters in a rugged and compact package. Paired with an OptoTest handheld optical power meter, the OP350 is ideal for mixed multimode and single-mode fiber testing, and is an essential tool for installers, contractors, and field technicians. 

Combining multiple source wavelengths and functions into one compact package means fewer instruments to take along and less equipment juggling for faster, more confident measurements. 

The OP350 is available in a wide range of models including LED-only, laser-only, and mixed LED and laser sources. Available wavelengths are 470nm to 1300nm for LED sources, and from 1310nm to 1625nm for laser sources. Ultra-stable LED and laser sources are available with zero warm-up time and are ideal for long term monitoring and optimal performance under varying optical return loss (ORL).


Excellent Optical Power Stability for Reliable and Repeatable Measurements

Typical stability over temperature is 0.35dB for LED sources and 0.6dB for laser sources. Stability over temperature for ultra-stable zero warm-up sources is as low as 0.2dB max for LED and laser sources.  

High Reconnection Repeatability

Reconnection repeatability of 0.1dB over a wide range of LED and laser wavelengths provides steady output power every time the OP350 is connected to perform measurements.

Standards Compliant LED and Laser Sources for Maximum Measurement Confidence

LED sources are controlled and certified to ensure compliance with Encircled Flux (EF) standards without additional conditioning patch leads. Laser sources are compliant with CWDM standards covering typical cable qualification for the O, E, S, C, and L bands, including the water absorption peak, 1625nm.

Supports One-Touch Autotest Capability Using a Compatible OptoTest Power Meter

One-touch Autotest synchronizes the instrument settings and test process with a compatible OptoTest optical power meter, such as the OP310, using the fiber under test. Enables fast, reliable, and repeatable testing in less time and with fewer user errors. Up to 6 wavelengths can be tested, with 3 wavelengths displayed simultaneously along with the nominal power level for each source.

Supports Tone Detection with Multi Fiber ID

Paired with an OptoTest optical power meter incorporating Multi Fiber ID, the OP350 can be used to identify up to 12 different fibers, in addition to standard optical test tones, i.e., 270Hz, 1KHz, and 2KHz. This makes continuity testing, polarity testing, and fault finding fast and reliable.

Optional VisiTest Visual Fault Locator

When used with a compatible OptoTest optical power meter, VisiTest blinks the active connected fiber, saving time, training, and guesswork. VisiTest output is both visible red and infrared, enabling long distance fault finding using a clip-on fiber identifier. 

Simple Controls with Large Backlit LCD Display

Multi-function buttons make accessing all measurement wavelengths and features easy and intuitive. High contrast display can be read in bright sun; backlight can be used in dark environments. 

Interchangeable Connectors are Protected Against Drops and Impact

The OP350 accommodates all industry standard fiber optic connectors, including FC, LC, ST, D4, MU, LSA-DIN47256, and E2000. Built-in bumpers and an integral dust cover protect the connector interface against damage and contamination. The dust cover doubles as a stand when used on a benchtop or other surface.

Flexible Power Options

The OP350 can be powered using two AA-type alkaline batteries, rechargeable NiMH batteries, or external micro USB power. Internal NiMH battery charging can be selected by moving a jumper in the battery compartment. Typical battery life using Autotest mode for LED sources is 80 hours, 90 hours for laser sources. 

Meets MIL PRF 28800F class 2 general requirements for maximum durability in the field

The OP350 features a strong, moisture resistant polycarbonate case with rubber edges and corners to withstand harsh outside environments. The case has been designed and tested to withstand one meter drops onto a hard surface. 


Field Insertion Loss Testing
Field Polarity Testing
Field MPO/MTP® Testing (large area detector)
Fiber Identification (when used with an optical power meter)

Talk to one of our sales engineers at +1(805) 987-1700 to learn more about our custom solutions.


Battery Life Laser/LED source: 90/80 hours in Autotest, typical
Size/Weight 7.5 x 4.1 x 1.4” (190 x 105 x 35 mm) / 0.9 lb (420 gm). Shipping 3.3 lb (1.5 kg)
LCD Size 2.9 x 2.2” (74 x 55 mm)
Operating /Storage -15 to 55 °C / -25 to 70 °C
Relative Humidity 0 ~ 95 %
Case Polycarbonate / rubber edges & corners, moisture resistance, 1-meter drop tested
Dust Cap Captive, functions as tilt bail when slid open
Power 2 x Alkaline / Lithium AA cells or 2 x NiMH AA cells, user selectable charging; Ext power input via
micro-USB; Selectable auto-off, low battery indicator, backlit display
Short term stability (dB) 0.04 0.06 0.06 N/A 0.01 N/A 0.01 For 15 min,
typical ± Δ 2 °C,
after warm up,
ORL < -25 dB
Stability over temp (dB) 0.6 0.6 0.6 N/A 0.35 N/A 0.35 Typical
OP350 Ultra Stable3
Short term stability (dB) 0.03 0.05 0.05 N/A 0.01 0.03 N/A For 15 min, max,
± Δ 3°C, no warm up
Stability over temp (dB) 0.2 0.2 0.2 N/A 0.35 0.2 N/A Max
OP350 / OP350 Ultra Stable
λ initial tolerance (nm) 20 6.5 20 5 N/A 20 15 at 25 °C
λ width, nm 3 < 1 3 3 N/A 35/48 25 FWHM, typical
λ nm/°C 0.4 0.1 0.4 0.1 0.4 0.4 N/A Typical
Mode Controlled Source N/A N/A N/A N/A Mode
N/A N/A 50/125 compliant:
IEC 61280-4-1 {Ed.1.0},
TIA 526-14A & TIA TSB-178.
repeatability4 dB
0.1 0.1 0.1 0.1 0.05 0.1 N/A 95% confidence
Modulation 270 Hz, 1 kHz, 2 kHz ± 2 %, 12 Multi-Fiber ID tones, 2 Hz blink for VisiTester
Output power level See table below for output power level of specific model
Output power
± 1 dB (for Laser/eLED @ SMF, Multimode LED @ 62.5 μm, POF @ 1 mm)

1: CWDM laser wavelengths: 1270, 1290, 1310, 1330, 1350, 1370, 1390, 1410, 1430, 1450, 1470, 1490, 1510, 1530, 1550, 1570, 1590, 1610 nm.
2: The VisiTester option mixes a laser VFL with Autotest, so at the power meter end, the active test fiber winks, making it obvious to the user. It also extends practical fault finding.
3: After inital warm-up, practical stability is affected by ambient temperature variations. On the OP350 Premium no warm-up , the stability is ± 0.03 dB.
4: The OP350 light sources achieve very high reconnection repeatability of 0.1dBm which provides steady output power every time connecting the sources.
5: Light source model with LED of these wavelengths do not support Autotest. 

Source Wavelength Sets (per port) SMF 50µ 62.5µ 1mm
850-1300nm LED N/A -22.5 -20 N/A
850-1300nm LED with VFL N/A -25.5 -23 N/A
470-520 nm LED N/A N/A N/A -13
1310-1550nm Laser 0 N/A N/A N/A
1310-1550nm Laser with VFL -3 N/A N/A N/A
1310-1550nm High Power +5 N/A N/A N/A
1310-1550nm Ultra Stable Laser -4 N/A N/A N/A
1310-1550-1625nm Laser -3 N/A N/A N/A
1310-1550-1625nm Laser with VFL -7 N/A N/A N/A
1310-1550-1625nm Ultra Stable Laser -7 N/A N/A N/A
1310-1490-1550-1625nm Laser -3 N/A N/A N/A
VFL Source +2 -35 -22.5 N/A

1: Instruments with multimode and single mode options will have two source ports. 


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